Amphetamines for attention deficit hyperactivity disorder (ADHD) in adults

Recommendation for Long-term Management of Adult Attention-Deficit/Hyperactivity Disorder in Military Populations, Veterans, and Dependents: A Narrative Review

INTRODUCTION

In addition to the higher burden of mental health disease in the military, there is a compounding antecedent association between behavioral health comorbidities and the treatment of attention-deficit/hyperactivity disorder (ADHD) in this population. Despite the low prevalence of new-onset ADHD in adults globally, the rate of stimulant (i.e., amphetamines) prescription is increasing. Stimulants can exacerbate mental health disease (often masquerading as ADHD symptomatology), precluding optimal treatment of the underlying etiology and imposing unnecessary dangerous side effects. This study aimed to evaluate the long-term safety and efficacy of stimulants for managing adult ADHD.

METHODS

A nine-member multidisciplinary team reviewed a PubMed search with the terms "adult," "ADHD," and "stimulant." Targeted PubMed and Google Scholar searches for "adult ADHD" paired with Food and Drug Administration -approved ADHD medications and Google Scholar literature using forward and reverse snowballing methods were performed for high-quality studies focusing on long-term treatment in ADHD. An evidence table and clinical algorithm were developed from the review.

RESULTS

Of the 1,039 results, 50 articles were fully reviewed, consisting of 21 descriptive and experimental studies, 18 observational, and 11 systematic reviews and meta-analyses. Illustrative cases within the structured discussion of the results highlighted ADHD and psychiatric comorbidities, risks, harms, and benefits of stimulant use, medication mechanisms of action, and limitations of the current evidence.

DISCUSSION

The dearth of high-quality studies on long-term ADHD management in adults fails to establish a causal relationship between stimulant use and physiological harm. Despite mixed evidence supporting the benefit of stimulants, there is clear evidence regarding the risk of harm. The serious risks of stimulants include arrhythmias, myocardial infarction, stroke/transient ischemic attack, sudden death, psychosis, and worsening of behavioral health disease. Additionally, there is a possible long-term risk of harm due to chronic sympathetic load (i.e., cardiovascular system remodeling). Stimulants pose a greater risk for addiction and abuse compared to other evidence-based nonstimulant medications that have similar effectiveness. Both stimulants and nonstimulants might promote favorable neuroanatomical changes for long-term improvement of ADHD symptoms, but nonstimulants (atomoxetine) have the pharmacological advantage of also mitigating the effects of sympathetic load (sympatholysis) and anxiety (anxiolysis). Given the physiological uncertainty of extended stimulant use for adults, especially older adults with vulnerable cardiovascular systems, clinicians should proceed cautiously when considering initiating or sustaining stimulant therapy. For long-term treatment of ADHD in adults, clinicians should consider nonstimulant alternatives (including behavioral therapy) due to the comparatively lower side effect risk and the possible additional benefit in patients with behavioral health comorbidities.

CONCLUSION

Long-term safety of stimulant use for adults with ADHD is uncertain, as existing studies are limited in quality and duration. This is particularly important for military populations with higher rates of mental health conditions. Managing ADHD and related conditions requires prioritizing cardiovascular safety, especially for older adults. Nonstimulant options can be helpful, especially in comorbid psychiatric disease. Before treating ADHD, ruling out and controlling other behavioral health conditions is essential to avoid masking or worsening underlying issues and reducing unnecessary medication side effects.

Lack of effect of methamphetamine on reward-related brain activity in healthy adults

INTRODUCTION

Stimulant drugs are thought to alter processing of rewarding stimuli. However, the mechanisms by which they do this are not fully understood.

METHOD

In this study we used EEG to assess effects of single doses of methamphetamine (MA) on neural responses during anticipation and receipt of reward in healthy volunteers. Healthy young men and women (N = 28) completed three sessions in which they received placebo, a low MA dose (10 mg) or a higher MA dose (20 mg) under double blind conditions. Subjective and cardiovascular measures were obtained, and EEG was used to assess brain activity during an electrophysiological version of the Monetary Incentive Delay (eMID) task.

RESULTS

EEG measures showed expected patterns during anticipation and receipt of reward, and MA produced its expected effects on mood and cardiovascular function. However, MA did not affect EEG responses during either anticipation or receipt of rewards.

CONCLUSIONS

These findings suggest that the effects of MA on EEG signals of reward processing are subtle, and not related to the drug's effects on subjective feelings of well-being. The findings contribute to our understanding of the neural effects of MA during behaviors related to reward.

Exploring the efficacy of dialectical behaviour therapy and methylphenidate on emotional comorbid symptoms in adults with attention Deficit/Hyperactivity disorder: Results of the COMPAS multicentre randomised controlled trial

This study evaluated the efficacy of dialectical behaviour group therapy (GPT) vs. individual clinical management (CM) and methylphenidate (MPH) vs. placebo (PLB) on emotional symptoms in adults with ADHD. This longitudinal multicentre RCT compared four groups (GPT+MPH, GPT+PLB, CM+MPH, and CM+PLB) over five assessment periods, from baseline to week 130. Emotional symptomatology was assessed using SCL-90-R subscales. Of the 433 randomised participants, 371 remained for final analysis. At week 13, the GPT+MPH group showed smaller reductions in anxiety symptoms than the CM groups, but the differences disappeared at subsequent assessments. Improvements in emotional symptom were significantly predicted by reductions in core ADHD symptoms in all groups except the GPT+MPH group. The unexpected lack of between-group differences may be explained by a "floor effect", different intervention settings (group vs. individual), and psychotherapy type. Multiple regression analyses suggest a more specific effect of combined interventions (GPT+MPH). Implications for clinical practice are discussed. Clinical trial registration: ISRCTN54096201 (Current Controlled Trials).

"On Suggestion" by John Bostock, 1923: A comparison with twenty-first century understandings of the placebo effect

OBJECTIVES

This paper describes Australian psychiatrist John Bostock's 1923 concept of suggestion and compares it to our understandings, in 2023, of the placebo effect.

CONCLUSIONS

Bostock's 1923 article on "suggestion" gives us a glimpse of the history of Australian psychiatry. It also stimulates thought about the current understandings of the placebo effect. Now, as then, placebo effects can play a critical role in patient outcomes. However, careful consideration is required to ensure contemporary ethical standards are met and harm is not done.

Methylphenidate-associated chest pain in a child

A young child was diagnosed with autism spectrum disorder with comorbid attention-deficit/hyperactivity disorder. His hyperactivity, impulsivity and absence of awareness towards danger increased his risk of harm and hence methylphenidate was indicated. Unfortunately, he developed chest pain eight months after the treatment initiation. We then stopped the stimulant and changed his treatment to atomoxetine, after which he no longer had chest pain. In the following illustrated case, we will discuss the cardiac side effect of methylphenidate.

Improvement of anxiety in ADHD following goal-focused cognitive remediation: a randomized controlled trial

Introduction

Despite the high prevalence and detrimental consequences of cognitive and executive dysfunction in ADHD, the evidence base of cognitive remediation in the adult ADHD population is sparse. Executive problems can increase both anxiety and depression in ADHD. Thcus, it is important to develop treatment options for adults with ADHD, aiming to improve goal-directed behavior and mood. Goal Management Training (GMT) is an intervention that has received empirical support in improving executive functions and mood in normal aging and for various neurological and psychiatric conditions. The present randomized controlled trial investigated the effects of a goal-focused intervention combining 1) group-based GMT incorporating psychoeducation about ADHD and 2) guidance in implementing individual goals for coping with executive problems in everyday life, compared to treatment as usual (TAU). The primary outcome was perceived executive functioning in everyday life. Secondary outcomes included psychological well-being (anxiety, depression, and coping with ADHD symptoms).

Methods

We recruited 81 adult participants with a verified ADHD diagnosis (Mage   = 31 years). Inclusion was based upon the presence of executive functioning complaints. The participants were randomly assigned to either the intervention or TAU. The intervention group (n = 41) received 16 hours of GMT and psychoeducation, in addition to 4 individual sessions focusing on formulating goals. The goals were assessed in 6 bi-weekly phone calls in the first three months following the group sessions. Participants in the TAU group (n = 40) received standard, individually-adapted follow-up in an outpatient psychiatric health care setting. All participants were assessed at baseline, post-intervention, and at 8-month follow-up (main measurement time point).

Results

Significant improvements in everyday executive functioning, psychological wellbeing, and symptoms of ADHD from baseline to 8-month follow-up were reported in both groups. The intervention group reported a significantly higher reduction in symptoms of anxiety compared to TAU. Conclusions. Our findings provide support for considering cognitive remediation as a treatment option for patients with ADHD.Clinical Trial Registration: https://clinicaltrials.gov/study/NCT04638283?term=NCT04638283&rank=1, identifier: NCT04638283.

Cost-effectiveness and budget impact analysis of lisdexamfetamine versus methylphenidate for patients under 18 with attention-deficit/hyperactivity disorder in Iran

BACKGROUND

Lisdexamfetamine (LDX) and Methylphenidate (MPH) are stimulant agents that have been shown to provide significant benefits in the management of attention-deficit/hyperactivity disorder (ADHD) in patients.

AIM

This study aimed to assess the cost-effectiveness and the budget impact of LDX compared to MPH as the first-line treatment for ADHD.

METHODS

A one-year cost-effectiveness analysis (CEA) was conducted to compare the effects of LDX and MPH in reducing disease symptoms and patient costs and improving quality of life (QoL) from a social perspective. Clinical data were obtained using the EQ-5D questionnaire. In contrast, economic data were sourced from the official website of the Iranian Food and Drug Association (FDA), the national book of tariffs, and specific questionnaires designed to evaluate patients' direct and indirect costs. 197 patients were included in the study, including individuals who sought psychiatric evaluation at a hospital in Mashhad and those who obtained ADHD medications from governmental pharmacies. The cost-effectiveness of the study medicine was assessed using the decision tree method, and the results were presented as the Incremental Cost-Effectiveness Ratio (ICER). Deterministic Sensitivity Analysis (DSA) and Probabilistic Sensitivity Analysis (PSA) were performed to assess the robustness of the findings. Additionally, a Budget Impact Analysis (BIA) was conducted over five years, considering three different scenarios, to evaluate the financial implications of incorporating LDX into the national pharmaceutical system.

RESULTS

The ICER for LDX therapy compared to MPH was estimated at USD 264.28 (with an incremental cost of USD 54.9, incremental effectiveness of 0.208, and Quality-Adjusted Life Years (QALYs) gained of 0.765). The PSA indicated a 0.994% probability of LDX being cost-effective, considering a threshold of USD 2450 per QALY. Furthermore, the DSA revealed that the acquisition cost of LDX influenced the model's sensitivity. The BIA demonstrated that incorporating LDX into Iran's healthcare system would result in a financial burden of approximately $368,566 in the first year, representing an additional cost of $11,154 compared to the non-availability of this medicine and the use of previous medications. It is projected that by 2027, the financial burden of treating ADHD with LDX will reach approximately USD 443,879 over five years, amounting to an increase of $71,154 compared to the absence of this medicine.

CONCLUSION

From a social perspective, the inclusion of LDX in the treatment regimen for ADHD is associated with higher costs and an increased financial burden. However, based on our analysis, LDX appears to be a cost-effective choice for managing ADHD in Iran when compared to MPH.

Sudden cardiac death in a young male endurance athlete

Sudden cardiac death (SCD) is a rare yet devastating event that can occur in young athletes. Although hypertrophic obstructive cardiomyopathy is the most common cause of SCD, some other genetic abnormalities have been identified as proarrhythmic. However, there is not routine screening for these other genetic abnormalities. Furthermore, consumption of caffeine, stimulant medication, or prolonged exercise can potentiate the underlying arrhythmic potential. In the event of SCD, advanced cardiac life support (ACLS) should be performed immediately and exactly. The authors present a case of an otherwise healthy young male who collapsed during a marathon and could not be resuscitated despite aggressive measures. After aggressive resuscitative efforts, the patient ultimately expired. A postmortem autopsy revealed no cardiac structural abnormalities, and the cause of death was determined to be cardiac arrhythmia of undetermined etiology. Postmortem genetic testing revealed a heterozygous variation in calcium voltage-gated channel auxiliary subunit beta 2 (CACNB2), a gene associated with arrhythmia and calcium channelopathy. Toxicology showed therapeutic levels of amphetamine. This case highlights the eminent risk of cardiac death in young athletes with proarrhythmic genetic variations, especially in the setting of endurance sport.

Psychoactive substance use in patients diagnosed with attention-deficit/hyperactivity disorder: an exploratory study

Introduction

Attention-deficit/hyperactivity disorder (ADHD) was originally treated as a neurodevelopmental disorder that occurs mainly in children and tends to diminish or disappear with age, but we now know that symptoms persist into adulthood in over 50% of ADHD patients. Undiagnosed individuals often turn to psychoactive substance to minimize the negative aspects of functioning and improve quality of life.

Methods

The study was conducted online using random sampling through a Facebook group administered by physicians and targeted to patients diagnosed with ADHD. The study was naturalistic and exploratory, therefore no hypothesis was made. 438 correctly completed questionnaires were received. Analysis of the results showed that people with ADHD turn to psychoactive substances relatively frequently.

Results

The most commonly used stimulants include alcohol, marijuana, 3,4-methylenedioxymethamphetamine (MDMA), amphetamine/methamphetamine, and psilocybin. In the study population, methylphenidate is the most commonly used drug among patients. After treatment with psychostimulants, the majority of respondents note a decrease in symptoms of hyperactivity disorder, especially in male patients.

Conclusion

It is necessary to perform proper diagnostics and actively look for ADHD symptoms in patients who tend to use psychoactive substances.

Prescription Stimulant Misuse Among Nursing Students: A Systematic Review

ABSTRACT

Nonmedical prescription stimulants are used to reduce symptoms of inattention, impulsivity, and hyperactivity in children and adults with attention-deficit hyperactivity/disorder. They are Schedule II controlled substances because of their high potential for dependence, and individuals who misuse them without a valid prescription are subject to criminal charges. Stimulant medications are also associated with common side effects (e.g., insomnia) as well as more serious but less common side effects (e.g., arrhythmias). Despite the potential health and legal consequences, misuse of prescription stimulants has become a public health crisis on college campuses in the United States. Neurocognitive enhancement is the primary reason that college students report misusing prescription stimulants, despite no enhancement of cognitive functioning when taken by healthy adults. Nursing students may be at risk for misuse because of their high levels of academic and clinical demands and because many start misusing in nursing school. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the databases PubMed, Science Direct, EBSCOhost, and Academic OneFile were systematically searched to investigate the (a) percentage of prescription stimulant misuse studies that have included nursing students, (b) prevalence of prescription stimulant misuse among nursing students, (c) motivations for prescription stimulant misuse among nursing students, and (d) demographic factors associated with increased use among nursing students. Results revealed that of the 197 studies conducted within the past decade (2010-2021), only 1.02% (two) included nursing students. Future studies must investigate the prevalence and nature of prescription stimulant misuse among nursing students.

Prescription amphetamines in people with opioid use disorder and co-occurring psychostimulant use disorder initiating buprenorphine: an analysis of treatment retention and overdose risk

BACKGROUND

Attention-deficit and hyperactivity disorder (ADHD) is frequently diagnosed in patients with substance use disorders (SUDs), including opioids. There remains concern about the safety and efficacy of prescription amphetamines (PAs) and their impact on effectiveness of opioid use disorder (OUD) treatment with buprenorphine.

OBJECTIVES

To assess the effect of PAs on OUD buprenorphine treatment retention and/or SUD-related emergency admission or drug-related poisonings.

METHODS

We used a retrospective cohort design with a secondary analysis of data from Merative MarketScan Commercial and Multi-State Medicaid Databases from 1 January 2006 to 31 December 2016. Individuals included were aged 12-64 years, had an OUD diagnosis and were prescribed buprenorphine. Our analysis used multivariable Cox regression to evaluate the relationship between PA receipt and time to buprenorphine discontinuation. The second part focused on subsamples of buprenorphine initiators who had either (1) any SUD-related emergency admissions or (2) drug-related poisoning. These outcomes were modelled as a function of PA exposure using conditional logistic regression models as part of a within-person, case-crossover design.

FINDINGS

Our sample had 90 269 patients with OUD (mean age 34.2 years (SD=11.3)) who initiated buprenorphine. Being prescribed a PA was associated with improved buprenorphine retention among individuals both with (adjusted HR (aHR) 0.91 (95% CI 0.86 to 0.97)) and without a concurrent psychostimulant use disorder (PSUD) (aHR 0.92 (95% CI 0.90 to 0.93)).

CONCLUSIONS

PA use was associated with improved buprenorphine retention in people with OUD with and without co-occurring PSUD. The risks of acute SUD-related events and drug-related poisonings associated with PA use did not differ when comparing PA-using days with days without PA use.

CLINICAL IMPLICATIONS

Patients with OUD on buprenorphine should receive treatment with a PA when indicated.

Person-centered language and pediatric ADHD research: a cross-sectional examination of stigmatizing language within medical literature

CONTEXT

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders in children and often goes untreated. A major barrier to treatment is the stigma surrounding the disorder, including from the educational and scientific community. Person-centered language (PCL) is associated with positive health outcomes, and its implementation is recommended by multiple professional groups, but its use has not been quantified for ADHD.

OBJECTIVES

The goal of this study is to quantify the adherence to PCL among ADHD-related journal publications utilizing a cross-sectional study design.

METHODS

We conducted a cross-sectional examination including a systematic search of PubMed, which encompasses MEDLINE, for ADHD-related articles from January 2014 to March 2021. All journals with at least 20 ADHD-related search returns, human research, and in the English language were included, totaling 5,308 articles from 88 journals. Articles were randomized, and the first 500 were screened for inclusion of prespecified, non-PCL terminology. After exclusion, 311 articles were retained.

RESULTS

Of the 311 retained articles, 131 (42.1%) adhered to PCL guidelines. Among articles with non-PCL, stigmatizing language such as "problem(s) with [the/a] child or problem child" and "suffers from" was found most frequently- occurring in 47.6% (148/311) and 5.8% (18/311) of the articles, respectively. We found no significant association between PCL adherence and study characteristics.

CONCLUSIONS

Our findings revealed that over half of the current ADHD literature did not adhere to PCL guidelines. Adherence to PCL by the scientific and medical community will increase the overall efforts to mitigate stigma and increase support for individuals with ADHD.

Systematic reviews of the acute effects of amphetamine on working memory and other cognitive performances in healthy individuals, with a focus on the potential influence of personality traits

OBJECTIVES

This research aimed to systematically review the acute effects of amphetamine (AMP), a dopamine-releasing agent, on working memory (WM) and other cognitive performances. The investigation also aimed to review the impact of personality traits on the subjective and objective effects of AMP and possible links between personality traits and effects of AMP.

METHODS

Previous double-blind controlled studies assessing the main effects of AMP on WM and other cognitive performances in healthy volunteers were systematically reviewed. An electronic search was performed in the PUBMED and SCOPUS databases. Narrative reviews of the influence of personality traits on the subjective and objective effects of AMP were included.

RESULTS

Nineteen WM studies were included in the current review. Seven studies found effects of AMP on spatial WM, but only one study found the effect of AMP on verbal WM. Thirty-seven independent studies on other aspects of cognitive performance were identified. Twenty-two reported effects of AMP on cognitive functions. Studies also showed that personality traits are associated with the subjective effects of AMP. However, few studies reported the impacts of personality traits on the objective (such as WM) effects of AMP.

CONCLUSION

Overall, findings indicate that AMP has mixed-effects on spatial WM and other cognitive functions, but it lacks effects on verbal WM. Although there are insufficient studies on objective measures, studies also indicated that the subjective effects of AMP administration are linked to between-person variations in personality traits.

Nanowired Delivery of Mesenchymal Stem Cells with Antioxidant Compound H-290/51 Reduces Exacerbation of Methamphetamine Neurotoxicity in Hot Environment

Military personnel are often exposed to hot environments either for combat operations or peacekeeping missions. Hot environment is a severe stressful situation leading to profound hyperthermia, fatigue and neurological impairments. To avoid stressful environment, some people frequently use methamphetamine (METH) or other psychostimulants to feel comfortable under adverse situations. Our studies show that heat stress alone induces breakdown of the blood-brain barrier (BBB) and edema formation associated with reduced cerebral blood flow (CBF). On the other hand, METH alone induces hyperthermia and neurotoxicity. These effects of METH are exacerbated at high ambient temperatures as seen with greater breakdown of the BBB and brain pathology. Thus, a combination of METH use at hot environment may further enhance the brain damage-associated behavioral dysfunctions. METH is well known to induce severe oxidative stress leading to brain pathology. In this investigation, METH intoxication at hot environment was examined on brain pathology and to explore suitable strategies to induce neuroprotection. Accordingly, TiO₂-nanowired delivery of H-290/51 (150 mg/kg, i.p.), a potent chain-breaking antioxidant in combination with mesenchymal stem cells (MSCs), is investigated in attenuating METH-induced brain damage at hot environment in model experiments. Our results show that nanodelivery of H-290/51 with MSCs significantly enhanced CBF and reduced BBB breakdown, edema formation and brain pathology following METH exposure at hot environment. These observations are the first to point out that METH exacerbated brain pathology at hot environment probably due to enhanced oxidative stress, and MSCs attenuate these adverse effects, not reported earlier.

Abstinence following intermittent methylphenidate exposure dose-dependently modifies brain glucose metabolism in the rat brain

Methylphenidate (MP) is a psychostimulant chronically prescribed for the treatment of attention deficit hyperactivity disorder (ADHD). Additionally, MP users may take breaks from using the medication during "drug holidays," which may include short-term or long-term breaks from medication. The present study utilized fluorodeoxyglucose (FDG) positron emission tomography (PET) to analyze the effects of chronic oral MP use and abstinence on brain glucose metabolism (BGluM) in rats at two different doses: high dose (HD) and low dose (LD). The schedule of treatment was 3 weeks on-treatment and 1 week off-treatment for a period of 13 weeks, followed by an abstinence period of 4 total weeks. Results showed that chronic MP treatment using this schedule did not lead to significant changes in BGluM when comparing the control to HD MP groups. However, significant activation in BGluM was observed after periods of abstinence between control and HD MP rats in the following brain regions: the trigeminal nucleus, reticular nucleus, inferior olive, lemniscus, mesencephalic reticular formation, inferior colliculus, and several areas of the cerebellum. These brain regions and functional brain circuit play a role in facial sensory function, the auditory pathway, organizing connections between the thalamus and cortex, motor learning, auditory function, control over eye movement, auditory information integration, and both motor and cognitive functions. These results, when considered with previous studies, indicate that MP schedule of use may have differing effects on BGluM. BGluM following long-term MP use was dependent on MP dose and schedule of use in rats. This study was conducted in non-ADHD model rats with the aim to establish an understanding of the effects of MP itself, especially given the growing chronic off-label and prescribed use of MP. Further studies are needed for analysis of the drug's effects on an ADHD model.

Sociodemographic and Clinical Factors Affecting Treatment Adherence in Adults with Attention Deficit and Hyperactivity Disorder

Background

This study aims to explore sociodemographic and clinical factors affecting medication adherence in adults with attention deficit and hyperactivity disorder and elicit dysfunctional domains and comorbidities with a focus on gender differences.

Methods

Patients were recruited from 2 specialty clinics using chart records in a natural treatment design. Adult attention deficit and hyperactivity disorder self-report scale, Diagnostic Interview for attention deficit and hyperactivity disorder in adults, was applied. Adherence is defined if the patient declared ≥80% adherence to medication throughout the last 8-12 weeks.

Results

From 205 attention deficit and hyperactivity disorder patients (male = 112 female = 93 (age (median) min-max = 29 (18-56)), 29% were non-adherent to attention deficit and hyperactivity disorder medication. In the multivariate analysis, having 2 or more comorbid disorders (P = .009), dysfunctions in academic/work (P = .049), and dysfunctions in family and other relationships (P = .047) increased the likelihood of adherence. Adherence rates did not significantly differ between methylphenidate and atomoxetine (P = .405). Women were more likely to have 2 or more comorbid psychiatric disorders (P = .004) and dysfunctions in social relationships (P = .001), free time activities, hobbies (P < .001), self-confidence, and self-image (P < .001).

Results

Nearly one-third of adult patients with attention deficit and hyperactivity disorder did not adhere to medication treatment. Comorbid psychiatric disorders and dysfunctions in life domains appear to increase the likelihood of adherence to attention deficit and hyperactivity disorder medications, possibly through increasing motivation for treatment. The effect of cognitive-behavioral therapy on compliance with attention deficit and hyperactivity disorder medication should further be explored with prospective controlled studies.

Conclusion

We suggest that future longitudinal studies use objective measures of adherence and confirm the role of dysfunctional life domains and comorbid psychiatric disorders as correlates of medication adherence.

Attention Deficit Hyperactivity Disorder and Substance Use Disorder: A Narrative Review

Attention deficit hyperactivity disorder (ADHD) has a growing incidence and prevalence in the United States and throughout the world, much of which is contributed to increased awareness of the condition and solidified diagnostic criteria. Substance use disorder (SUD) similarly has seen a sharp increase, particularly with the rising cases of opioid abuse. Management of ADHD is done primarily with pharmacologic therapy, often stimulants and with psychosocial interventions (i.e., exercise, meditation, peer-to-peer intervention, etc.) for adjunctive management. Management of SUD involves cessation and treatment based on the underlying drug of abuse. Many clinicians are uncomfortable treating ADHD in patients with SUD based on concerns the intervention may lead to an adverse event, including drug relapse, and the development of other psychiatric comorbidities. Concerns also arise about stimulants acting as a gateway drug in adolescents leading to the onset of SUD. Thus, in this narrative review, we aim to shed light on ADHD in relation to SUD and to provide clinical insight based on the current scientific literature on the topic. ADHD causes lesions in subcortical structures in the basal ganglia and limbic system. Treatment of ADHD with stimulants has been shown to normalize malformed neuroanatomical variations and lead to improved long-term outcomes compared to non-treatment of ADHD. Based on current scientific literature, it is recommended to treat ADHD with guideline-directed pharmacologic agents including stimulants along with non-pharmacologic interventions primarily exercise. There may be some improvement in reducing risky behavior, such as substance abuse, and may even help prevent the development of SUD.

The Association of Oral Stimulant Medication Adherence with Work Productivity among Adults with ADHD

OBJECTIVE

Examine associations between oral psychostimulant pharmacotherapy adherence, work productivity, and related indirect costs among US adults with ADHD.

METHODS

Medication adherence (Medication Adherence Reasons Scale [MAR-Scale]), work productivity and activity impairment (Work Productivity and Activity Impairment-General Health questionnaire), and ADHD symptom level (Adult ADHD Self-Report Scale version 1.1 Symptom Checklist) were assessed in this noninterventional online survey of adults who self-reported having an ADHD diagnosis and were currently receiving oral psychostimulant treatment for ≥3 months.

RESULTS

Of 602 respondents, 395 had low/medium adherence (LMA: MAR-Scale total score ≥1) and 207 had high adherence (HA: MAR-Scale total score 0). After adjusting for covariates, the LMA group had significantly greater levels of absenteeism, absenteeism-related indirect costs, and total indirect costs (all p < .01) than the HA group.

CONCLUSION

In adults with ADHD using oral psychostimulants, lower medication adherence was associated with greater absenteeism and indirect costs.

Extended-release methylphenidate for attention deficit hyperactivity disorder (ADHD) in adults

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a psychiatric diagnosis increasingly used in adults. The recommended first-line pharmacological treatment is central nervous system (CNS) stimulants, such as methylphenidate, but uncertainty remains about its benefits and harms.

OBJECTIVES

To assess the beneficial and harmful effects of extended-release formulations of methylphenidate in adults diagnosed with ADHD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, nine other databases and four clinical trial registries up to February 2021. We searched 12 drug regulatory databases for clinical trial data up to 13 May 2020. In addition, we cross-referenced all available trial identifiers, handsearched reference lists, searched pharmaceutical company databases, and contacted trial authors.

SELECTION CRITERIA

Randomised, double-blind, parallel-group trials comparing extended-release methylphenidate formulations at any dose versus placebo and other ADHD medications in adults diagnosed with ADHD.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. We assessed dichotomous outcomes as risk ratios (RRs), and rating scales and continuous outcomes as mean differences (MDs) or standardised mean differences (SMDs). We used the Cochrane risk of bias tool to assess risks of bias, and GRADE to assess the certainty of the evidence. We meta-analysed the data using a random-effects model. We assessed three design characteristics that may impair the trial results' 'generalisability'; exclusion of participants with psychiatric comorbidity; responder selection based on previous experience with CNS stimulants; and risk of withdrawal effects. Our prespecified primary outcomes were functional outcomes, self-rated ADHD symptoms, and serious adverse events. Our secondary outcomes included quality of life, ADHD symptoms rated by investigators and by peers such as family members, cardiovascular variables, severe psychiatric adverse events, and other adverse events.

MAIN RESULTS

We included 24 trials (5066 participants), of which 21 reported outcome data for this review. We also identified one ongoing study. We included documents from six drug regulatory agencies covering eight trials. Twenty-one trials had an outpatient setting and three were conducted in prisons. They were primarily conducted in North America and Europe. The median participant age was 36 years. Twelve trials (76% of participants) were industry-sponsored, four (14% of participants) were publicly funded with industry involvement, seven (10% of participants) were publicly funded, and one had unclear funding. The median trial duration was eight weeks. One trial was rated at overall unclear risk of bias and 20 trials were rated at overall high risk of bias, primarily due to unclear blinding of participants and investigators, attrition bias, and selective outcome reporting. All trials were impaired in at least one of the three design characteristics related to 'generalisability'; for example, they excluded participants with psychiatric comorbidity such as depression or anxiety, or included participants only with a previous positive response to methylphenidate, or similar drugs. This may limit the trials' usefulness for clinical practice, as they may overestimate the benefits and underestimate the harms. Extended-release methylphenidate versus placebo (up to 26 weeks) For the primary outcomes, we found very low-certainty evidence that methylphenidate had no effect on 'days missed at work' at 13-week follow-up (mean difference (MD) -0.15 days, 95% confidence interval (CI) -2.11 to 1.81; 1 trial, 409 participants) or serious adverse events (risk ratio (RR) 1.43, CI 95% CI 0.85 to 2.43; 14 trials, 4078 participants), whereas methylphenidate improved self-rated ADHD symptoms (small-to-moderate effect; SMD -0.37, 95% CI -0.43 to -0.30; 16 trials, 3799 participants). For secondary outcomes, we found very low-certainty evidence that methylphenidate improved self-rated quality of life (small effect; SMD -0.15, 95% CI -0.25 to -0.05; 6 trials, 1888 participants), investigator-rated ADHD symptoms (small-to-moderate effect; SMD -0.42, 95% CI -0.49 to -0.36; 18 trials, 4183 participants), ADHD symptoms rated by peers such as family members (small-to-moderate effect; SMD -0.31, 95% CI -0.48 to -0.14; 3 trials, 1005 participants), and increased the risk of experiencing any adverse event (RR 1.27, 95% CI 1.19 to 1.37; 14 trials, 4214 participants). We rated the certainty of the evidence as 'very low' for all outcomes, primarily due to high risk of bias and 'indirectness of the evidence'. One trial (419 participants) had follow-up at 52 weeks and two trials (314 participants) included active comparators, hence long-term and comparative evidence is limited.

AUTHORS' CONCLUSIONS

We found very low-certainty evidence that extended-release methylphenidate compared to placebo improved ADHD symptoms (small-to-moderate effects) measured on rating scales reported by participants, investigators, and peers such as family members. Methylphenidate had no effect on 'days missed at work' or serious adverse events, the effect on quality of life was small, and it increased the risk of several adverse effects. We rated the certainty of the evidence as 'very low' for all outcomes, due to high risk of bias, short trial durations, and limitations to the generalisability of the results. The benefits and harms of extended-release methylphenidate therefore remain uncertain.

Rise, and pronounced regional variation, in methylphenidate, amphetamine, and lisdexamfetamine distribution in the United States

Background

The prescription stimulants methylphenidate, amphetamine, and lisdexamfetamine are sympathomimetic drugs with therapeutic use. They are designated in the United States as Schedule II substances, defined by the 1970 Controlled Substances Act as having a “high potential for abuse”. Changing criteria for the diagnosis of Attention Deficit Hyperactivity Disorder in 2013 and the approval of lisdexamfetamine for binge eating disorder in 2015 may have impacted usage patterns. This report compared the pharmacoepidemiology of these stimulants in the United States from 2010–2017.

Methods

Distribution of amphetamine, methylphenidate, lisdexamfetamine were examined via weights extracted from the Drug Enforcement Administration’s (DEA) Automated Reports and Consolidated Ordering System (ARCOS). Median stimulant Daily Dosage per patient was determined for a regional analysis. The percent of cost and prescriptions attributable to each stimulant and atomoxetine in Medicaid from the “Drug Utilization 2018 - National Total” from the Centers for Medicare and Medicaid was determined.

Results

There was a rise in amphetamine (+67.5%) and lisdexamfetamine (+76.7%) from 2010–2017. The change in methylphenidate (−3.0%) was modest. Persons/day stimulant usage was lower in the West than in other US regions from 2014-2017. There was a negative correlation (r(48) = −0.43 to −0.65, p < .05) between the percent Hispanic population per state and the Daily Dosage/population per stimulant. Methylphenidate formulations accounted for over half (51.7%) of the $3.8 billion reimbursed by Medicaid and the plurality (45.4%) of the 22.0 million prescriptions. Amphetamine was responsible for less than one-fifth (18.4%) of cost but one-third of prescriptions (33.6%). Lisdexamfetamine’s cost (26.0%) exceeded prescriptions (16.3%).

Conclusion

The rising amphetamine and lisdexamfetamine distribution may correspond with a rise in adult ADHD diagnoses. Regional analysis indicates that stimulant distribution in the West may be distinct from that in other regions. The lower stimulant distribution in areas with greater Hispanic populations may warrant further study.

The Effects of Drug Treatments for ADHD in Measures of Cognitive Performance

Based on core symptoms of inattention and deficient impulse control, and the identification of effective pharmacotherapies such as amphetamine (AMP; Adderall^®), methylphenidate (MPH; Ritalin^®), and atomoxetine (ATX; Strattera^®), ADHD is a clinical condition which provides opportunity for translational research. Neuropsychological tests such as the 5-Choice and Continuous Performance Tasks, which measure aspects of attention and impulse control in animals and humans, provide scope for both forward (animal to human) and reverse (human to animal) translation. Rodent studies support pro-attentive effects of AMP and MPH and effectiveness in controlling some forms of impulsive behavior. In contrast, any pro-attentive effects of ATX appear to be less consistent, the most reliable effects of ATX are recorded in tests of impulsivity. These differences may account for AMP and MPH being recognized as first-line treatments for ADHD with a higher efficacy relative to ATX. DSM-5 classifies three "presentations" of ADHD: predominantly inattentive type (ADHD-I), predominantly hyperactive/impulsive type (ADHD-HI), or combined (ADHD-C). Presently, it is unclear whether AMP, MPH, or ATX has differential levels of efficacy across these presentation types. Nonetheless, these studies encourage confidence for the forward translation of NCEs in efforts to identify newer pharmacotherapies for ADHD.

Characterizing prescription stimulant nonmedical use (NMU) among adults recruited from Reddit

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Adults reporting past 5-year non-oral prescription stimulant NMU were studied.

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Non-oral NMU preferences were snorting (59%) injecting (4%) or smoking (1%).

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Polysubstance use was reported by 79.1% of the sample.

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Route of administration and motivation for prescription stimulant NMU were related.

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Prescription stimulant oral and intranasal NMU was to enhance performance.

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Prescription stimulant intravenous and smoking NMU was to get high.

Objective

Increased prescription stimulant nonmedical use (NMU) is part of a growing polysubstance use landscape. The purpose of the present study was to characterize prescription stimulant NMU among adults reporting past 5-year non-oral prescription stimulant NMU.

Methods

Adults who reported non-oral prescription stimulant NMU within the last 5 years were recruited by banner ads placed on the Reddit website between February and September 2019. Types of prescription stimulants used, routes of administration, preferred routes of administration, motivations for prescription stimulant NMU, concurrent substances used simultaneously during prescription stimulant NMU, illicit substances used and factors impacting prescription stimulant NMU were queried.

Results

Respondents (n = 225) were male (86.2%), non-Hispanic (92.4%), white (78.2%), between 18 and 24 (48.0%) or 25–34 (43.1%) years with some amount of college education (81.3%). Most reported lifetime intranasal (93.8%) or oral use (85.2%). Prescription stimulants were diverted: 64.5% reported the prescription stimulants were given to them by a family or a friend and 10.5% reported that they had stolen these medications from a family or friend. Preferred route of administration was oral use (70.2%). Motivations to use were stratified by route of administration: intranasal (55.6%) or oral (63.0%) use was primarily endorsed as an attempt to enhance performance at work or at school; use by injection (57.1%) or smoking (62.5%) was primarily endorsed to get high. Most of the sample reported concurrent drug use (79.1%) including tobacco (57.3%), marijuana (52.0%), caffeine (47.6%) or alcohol (41.8%), among others. When excluding licit substances, 30.7% reported using 1 illicit substance concurrently with prescription stimulants and 25.3% reported using 2 or more illicit substances concurrently with prescription stimulants. Whether participants would undertake prescription stimulant NMU was determined by their work/school schedules or the location of the NMU (48.9%) whereas the route of administration employed was primarily influenced by the desired feeling or effect (56.9%).

Conclusions

Adults reporting lifetime non-oral prescription stimulant NMU engage in substantial risky behaviors that in addition to alternate routes of administration include polysubstance use, diversion and concurrent substance use.

Developmental exposure to methylmercury and ADHD, a literature review of epigenetic studies

Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that affects the competence of academic performance and social wellness in children and adults. The causes of ADHD are unclear. Both genetic and environmental factors contribute to the development of ADHD. The behavioral impairments in ADHD are associated with epigenetic changes in genes that are important for neurodevelopment. Among environmental causes of ADHD, the neurotoxin methylmercury (MeHg) is associated with an increased risk for ADHD. Developing children are susceptible to neurotoxic effects of prenatal MeHg exposure. Human epidemiology studies have shown that prenatal MeHg exposure could invoke epigenetic changes in genes that are involved in ADHD. In addition, the pathogenesis of ADHD involves dopaminergic system, which is a target of developmental MeHg exposure. MeHg-induced alterations in the dopaminergic system have a profound impact on behavioral functions in adults. As a trace level of MeHg (around nM) can induce long-lasting behavioral alterations, potential mechanisms of MeHg-induced functional changes in the dopaminergic system may involve epigenetic mechanisms. Here, we review the relevant evidence on developmental MeHg exposures and the risk for ADHD. We also point out research gaps in understanding environmental causes of ADHD.

Assessment of Stimulant Use and Cardiovascular Event Risks Among Older Adults

IMPORTANCE

Use of stimulants continues to increase among older adults for a variety of indications. An association between stimulant use and increased risk of cardiovascular (CV) events has been established among children and young adults, but few studies have explored the risk of CV events among older patients, a group with increased baseline risk.

OBJECTIVE

To evaluate the association between stimulant use and risk of CV events among older adults.

DESIGN, SETTING, AND PARTICIPANTS

This propensity score-matched cohort study, with 4 nonusers per 1 user, was conducted from July 1, 2017, to June 27, 2019, using data from population-based health care databases from Ontario, Canada, from January 1, 2002, to December 31, 2016. Included individuals were outpatients aged 66 years or older.

EXPOSURES

Initiation of a prescription stimulant.

MAIN OUTCOMES AND MEASURES

The primary outcome was a CV event, defined as a composite of emergency department visit or hospitalization for myocardial infarction, stroke or transient ischemic attack (TIA), or ventricular arrhythmia. Risk of CV event was assessed at 30 days, 180 days, and 365 days after initiation of stimulants from Cox proportional hazard models. A secondary analysis assessed each component of the primary outcome separately.

RESULTS

Among 6457 older adults who initiated a prescription stimulant (ie, the exposed group) and 24 853 older adults who did not initiate such treatment (ie, the unexposed group), the distribution of baseline patient characteristics was well balanced after matching (sex: 3173 [49.1%] men vs 12 112 [48.7%] men; standardized difference, 0.01; median [IQR] age: 74 [69-80] years vs 74 [69-80] years; standardized difference, 0.01). Within this cohort, there were 932 CV events during the 365-day follow-up (5.11 events per 100 person-years among individuals who initiated stimulants). In the primary analysis, stimulant initiation was associated with increased risk of CV events at 30 days (hazard ratio [HR], 1.4; 95% CI, 1.1-1.8) but not at 180 days (HR, 1.2; 95% CI, 0.9-1.6) or 365 days (HR, 1.0; 95% CI, 0.6 to 1.8). In the secondary analysis, stimulant initiation was associated with increased risk of ventricular arrhythmias (HR, 3.0; 95% CI, 1.1-8.7) and stroke or TIA (HR, 1.6; 95% CI, 1.1-2.1) at 30 days.

CONCLUSIONS AND RELEVANCE

This cohort study found that stimulant use was associated with an early increase in CV events among older adults with no association for long-term use.

Effects of Neurofeedback in Children with Attention-Deficit/Hyperactivity Disorder: A Systematic Review

Attention deficit/hyperactivity disorder (ADHD) is one of the most frequent neurodevelopmental disorders in childhood and adolescence. Choosing the right treatment is critical to controlling and improving symptoms. An innovative ADHD treatment is neurofeedback (NF) that trains participants to self-regulate brain activity. The aim of the study was to analyze the effects of NF interventions in children with ADHD. A systematic review was carried out in the CINAHL, Medline (PubMed), Proquest, and Scopus databases, following the PRISMA recommendations. Nine articles were found. The NF improved behavior, allowed greater control of impulsivity, and increased sustained attention. In addition, it improved motor control, bimanual coordination and was associated with a reduction in theta waves. NF combined with other interventions such as medication, physical activity, behavioral therapy training, or attention training with brain-computer interaction, reduced primary ADHD symptoms. Furthermore, more randomized controlled trials would be necessary to determine the significant effects.

Relationship Between Treatment Duration and Efficacy of Pharmacological Treatment for ADHD: A Meta-Analysis and Meta-Regression of 87 Randomized Controlled Clinical Trials

Objective: To determine the relationship between treatment duration and the efficacy of pharmacological treatment for reducing ADHD symptoms. Method: We conducted a systematic review of randomized, double-blind, placebo-controlled clinical trials investigating the efficacy of pharmacological interventions in patients with ADHD. The last bibliographic search was performed in April 15, 2019. The effect of treatment duration on efficacy was studied using meta-regression. Results: A total of 87 studies lasting from 3 to 28 weeks were included. Pharmacological treatment improved ADHD symptom severity by -7.35 points. Treatment duration did not moderate the efficacy of pharmacological treatment. Consistent results were found for psychostimulant drugs, methylphenidate, amphetamine derivatives, atomoxetine, and α2-agonists. A negative correlation was found between baseline ADHD severity efficacy (Coefficient = -.250, p = .013). Conclusion: The efficacy of pharmacological treatment for ADHD remains stable over time. A greater efficacy in more severe patients is suggested.

Lifetime evolution of ADHD treatment

Attention-deficit hyperactivity disorder (ADHD), has been traditionally considered a neurodevelopmental disorder affecting children and adolescents characterized by inattention, hyperactivity, disruptive behavior, and impulsivity. Although still debated, it is evident that ADHD is also present in adulthood, but this diagnosis is rarely carried out, mainly for the frequent comorbidity with other psychiatric and/or substance abuse disorders. Given the need to shed more light on the pharmacological treatment of ADHD, we performed a naturalistic review to review and comment on the available literature of ADHD treatment across the lifespan. Indeed, stimulants are endowed of a prompt efficacy and safety, whilst non-stimulants, although requiring some weeks to be fully effective, are useful when a substance abuse history is detected. In any case, the pharmacological management of ADHD appears to be still largely influenced by the individual experience of the clinicians. Further longitudinal studies with a careful and detailed characterization of participants across different phases of the lifespan are also required to provide relevant confirmations (or denials) regarding pharmacological treatments amongst the different age groups.

Resveratrol adjunct to methylphenidate improves symptoms of attention-deficit/hyperactivity disorder: a randomized, double-blinded, placebo-controlled clinical trial

Current pharmacological approaches have failed to provide complete remission for patients with Attention-Deficit/Hyperactivity Disorder (ADHD). This study aimed to evaluate the efficacy and tolerability of resveratrol (that have been shown to have antioxidative, anti-inflammatory, and anti-apoptotic effects) as an adjunct to methylphenidate in pharmacologic treatment of ADHD. This 8-week, double-blinded, placebo-controlled trial randomized 66 participants to receive either 500 mg/day resveratrol or matched placebo in addition to methylphenidate. ADHD symptoms were evaluated in the patients using the Parent and Teacher versions of ADHD-Rating Scale (ADHD-RS) at three measurement points with time intervals of 4 weeks. Furthermore, the tolerability of the treatment strategies was systematically compared. Repeated measures analysis demonstrated a significant effect for time-treatment interaction on all three subscales of the Parent ADHD-RS during the trial period (total: p = 0.015; inattention: p = 0.032; hyperactivity/impulsivity: p = 0.036). Nevertheless, the effect for time-treatment interaction was not significant for the Teacher version of ADHD-RS (total: F = 0.81, df = 1.33, p = 0.401; inattention: F = 0.57, df = 1.37, p = 0.507; hyperactivity/impulsivity: F = 0.65, df = 1.34, p = 0.466). The frequencies of complications in the treatment groups were similar. Resveratrol administration for a duration of 8 weeks improved characteristic symptoms in patients with ADHD according to their parents. Further investigations containing larger sample sizes, longer supplementation periods, and dose-response evaluations are required to replicate these findings in ADHD children more confidently.

EMA and FDA psychiatric drug trial guidelines: assessment of guideline development and trial design recommendations

AIMS

The European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) produce guidelines for the design of pivotal psychiatric drug trials used in new drug applications. It is unknown who are involved in the guideline development and what specific trial design recommendations they give.

METHODS

Cross-sectional study of EMA Clinical Efficacy and Safety Guidelines and FDA Guidance Documents. Study outcomes: (1) guideline committee members and declared conflicts of interest; (2) guideline development and organisation of commenting phases; (3) categorisation of stakeholders who comment on draft and final guidelines according to conflicts of interest ('industry', 'not-industry but with industry-related conflicts', 'independent', 'unclear'); and (4) trial design recommendations (trial duration, psychiatric comorbidity, 'enriched design', efficacy outcomes, comparator choice). Protocol registration https://doi.org/10.1101/2020.01.22.20018499 (27 January 2020).

RESULTS

We included 13 EMA and five FDA guidelines covering 15 psychiatric indications. Eleven months after submission, the EMA had not processed our request regarding committee member disclosures. FDA offices draft the Guidance Documents, but the Agency is not in possession of employee conflicts of interest declarations because FDA employees generally may not hold financial interests (although some employees may hold interests up to $15,000). The EMA and FDA guideline development phases are similar; drafts and final versions are publicly announced and everybody can submit comments. Seventy stakeholders commented on ten guidelines: 38 (54%) 'industry', 18 (26%) 'not-industry but with industry-related conflicts', six (9%) 'independent' and eight (11%) 'unclear'. They submitted 1014 comments: 640 (68%) 'industry', 243 (26%) 'not-industry but with industry-related conflicts', 44 (5%) 'independent' and 20 (2%) 'unclear' (67 could not be assigned to a specific stakeholder). The recommended designs were generally for trials of short duration; with restricted trial populations; allowing previous exposure to the drug; and often recommending rating scale efficacy outcomes. EMA mainly recommended three arm designs (both placebo and active comparators), whereas FDA mainly recommended placebo-controlled designs. There were also other important differences and FDA's recommendations regarding the exclusion of psychiatric comorbidity seemed less restrictive.

CONCLUSIONS

The EMA and FDA clinical research guidelines for psychiatric pivotal trials recommend designs that tend to have limited generalisability. Independent and non-conflicted stakeholders are underrepresented in the guideline development. It seems warranted with more active involvement of scientists and independent organisations without conflicts of interest in the guideline development process.

Pharmacotherapy for Attention-Deficit/Hyperactivity Disorder and Retention in Outpatient Substance Use Disorder Treatment: A Retrospective Cohort Study

OBJECTIVE

To assess the relationship between short- and longer-term retention in outpatient substance use disorder (SUD) treatment and pharmacotherapy for comorbid attention-deficit/hyperactivity disorder (ADHD).

METHODS

In this retrospective cohort study conducted in a single addiction psychiatry clinic, electronic health record data from July 14, 2014, through January 15, 2020, were queried for clinical ADHD diagnosis (DSM-5 criteria), ADHD pharmacotherapy, treatment duration, demographic variables, comorbid psychiatric and SUD diagnoses, and buprenorphine therapy. Individuals with ADHD (n = 203) were grouped by ADHD pharmacotherapy status (171 receiving medication compared to 32 receiving none). Kaplan-Meier and Cox proportional hazards regression analyses were performed and assessed for significance.

RESULTS

ADHD was clinically diagnosed in 9.4% of outpatients and was associated with younger age, comorbid cocaine use, and private insurance (P < .001). Individuals receiving no ADHD pharmacotherapy were younger than those receiving medication (P = .003). Compared to no ADHD medication, ADHD pharmacotherapy was associated with greater long-term retention, with apparent group half-lives of 9 months and 36 months, respectively (P < .001). Individuals receiving no ADHD medication had a 4.9-fold increased likelihood of attrition within 90 days (P = .041). Regression analysis showed only ADHD pharmacotherapy to be significantly associated with treatment retention (hazard ratio = 0.59; 95% CI, 0.40-0.86; P = .008).

CONCLUSIONS

ADHD pharmacotherapy is robustly associated with improved short- and longer-term retention in outpatient SUD treatment. The retrospective, nonrandomized naturalistic study design limits causal inference. Further studies addressing unmeasured covariates and associated risks of treatment in adults with ADHD and SUD are necessary.

Attention-deficit/hyperactivity disorder and the explore/exploit trade-off

The ability to maximize rewards and minimize the costs of obtaining them is vital to making advantageous explore/exploit decisions. Exploratory decisions are theorized to be greater among individuals with attention-deficit/hyperactivity disorder (ADHD), potentially due to deficient catecholamine transmission. Here, we examined the effects of ADHD status and methylphenidate, a common ADHD medication, on explore/exploit decisions using a 6-armed bandit task. We hypothesized that ADHD participants would make more exploratory decisions than controls, and that MPH would reduce group differences. On separate study days, adults with (n = 26) and without (n = 23) ADHD completed the bandit task at baseline, and after methylphenidate or placebo in counter-balanced order. Explore/exploit decisions were modeled using reinforcement learning algorithms. ADHD participants made more exploratory decisions (i.e., chose options without the highest expected reward value) and earned fewer points than controls in all three study days, and methylphenidate did not affect these outcomes. Baseline exploratory choices were positively associated with hyperactive ADHD symptoms across all participants. These results support several theoretical models of increased exploratory choices in ADHD and suggest the unexplained variance in ADHD decisions may be due to less value tracking. The inability to suppress actions with little to no reward value may be a key feature of hyperactive ADHD symptoms.

Immediate-release methylphenidate for attention deficit hyperactivity disorder (ADHD) in adults

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is characterized by symptoms of inattention or impulsivity or both, and hyperactivity, which affect children, adolescents, and adults. In some countries, methylphenidate is the first option to treat adults with moderate or severe ADHD. However, evidence on the efficacy and adverse events of immediate-release (IR) methylphenidate in the treatment of ADHD in adults is limited and controversial.

OBJECTIVES

To evaluate the efficacy and harms (adverse events) of IR methylphenidate for treating ADHD in adults.

SEARCH METHODS

In January 2020, we searched CENTRAL, MEDLINE, Embase, eight additional databases and three trial registers. We also searched internal reports on the European Medicines Agency and the US Food and Drug Administration websites. We checked citations of included trials to identify additional trials not captured by the electronic searches.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing IR methylphenidate, at any dose, with placebo or other pharmacological interventions (including extended-release formulations of methylphenidate) for ADHD in adults. Primary outcomes comprised changes in the symptoms of ADHD (efficacy) and harms. Secondary outcomes included changes in the clinical impression of severity and improvement, level of functioning, depression, anxiety and quality of life. Outcomes could have been rated by investigators or participants.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently on the characteristics of the trials, participants, interventions; outcomes and financial conflict of interests. We resolved disagreements by discussion or consulting a third review author. We obtained additional, unpublished information from the authors of one included trial that had reported efficacy data in a graph. We calculated mean differences (MDs) or standardized MDs (SMDs) with 95% confidence intervals (CIs) for continuous data reported on the same or different scales, respectively. We summarized dichotomous variables as risk ratios (RRs) with 95% CI.

MAIN RESULTS

We included 10 trials published between 2001 and 2016 involving 497 adults with ADHD. Three trials were conducted in Europe and one in Argentina; the remaining trials did not report their location. The RCTs compared IR methylphenidate with placebo, an osmotic-release oral system (OROS) of methylphenidate (an extended-release formulation), an extended-release formulation of bupropion, lithium, and Pycnogenol® (maritime pine bark extract). Participants comprised outpatients, inpatients in addiction treatment, and adults willing to attend an intensive outpatient program for cocaine dependence. The duration of the follow-up ranged from 6 to 18 weeks. IR methylphenidate versus placebo We found very low-certainty evidence that, compared with placebo, IR methylphenidate may reduce symptoms of ADHD when measured with investigator-rated scales (MD -20.70, 95% CI -23.97 to -17.43; 1 trial, 146 participants; end scores; Adult ADHD Investigator Symptom Report Scale (AISRS), scored from 0 to 54), but the evidence is uncertain. The effect of IR methylphenidate on ADHD symptoms when measured with participant-rated scales was moderate, but the certainty of the evidence is very low (SMD -0.59, 95% CI -1.25 to 0.06; I² = 69%; 2 trials, 138 participants; end scores). There is very low-certainty evidence that, compared with placebo, IR methylphenidate may reduce the clinical impression of the severity of ADHD symptoms (MD -0.57, 95% CI -0.85 to -0.28; 2 trials, 139 participants; I² = 0%; change and end scores; Clinical Global Impression (CGI)-Severity scale (scored from 1 (very much improved) to 7 (very much worse))). There is low-certainty evidence that, compared with placebo, IR methylphenidate may slightly impact the clinical impression of an improvement in symptoms of ADHD (MD -0.94, 95% CI -1.37 to -0.51; 1 trial, 49 participants; end scores; CGI-Improvement scale (scored from 1 (very much improved) to 7 (very much worse))). There is no clear evidence of an effect on anxiety (MD -0.20, 95% CI -4.84 to 4.44; 1 trial, 19 participants; change scores; Hamilton Anxiety Scale (HAM-A; scored from 0 to 56); very low-certainty evidence) or depression (MD 2.80, 95% CI -0.09 to 5.69; 1 trial, 19 participants; change scores; Hamilton Depression Scale (HAM-D; scored from 0 to 52); very low-certainty evidence) in analyses comparing IR methylphenidate with placebo. IR methylphenidate versus lithium Compared with lithium, it is uncertain whether IR methylphenidate increases or decreases symptoms of ADHD (MD 0.60, 95% CI -3.11 to 4.31; 1 trial, 46 participants; end scores; Conners' Adult ADHD Rating Scale (scored from 0 to 198); very low-certainty evidence); anxiety (MD -0.80, 95% CI -4.49 to 2.89; 1 trial, 46 participants; end scores; HAM-A; very low-certainty evidence); or depression (MD -1.20, 95% CI -3.81 to 1.41, 1 trial, 46 participants; end scores; HAM-D scale; very low-certainty evidence). None of the included trials assessed participant-rated changes in symptoms of ADHD, or clinical impression of severity or improvement in participants treated with IR methylphenidate compared with lithium. Adverse events were poorly assessed and reported. We rated all trials at high risk of bias due to selective outcome reporting of harms and masking of outcome assessors (failure to blind outcome assessor to measure adverse events). Overall, four trials with 203 participants who received IR methylphenidate and 141 participants who received placebo described the occurrence of harms. The use of IR methylphenidate in these trials increased the risk of gastrointestinal complications (RR 1.96, 95% CI 1.13 to 2.95) and loss of appetite (RR 1.77, 95% CI 1.06 to 2.96). Cardiovascular adverse events were reported inconsistently, preventing a comprehensive analysis. One trial comparing IR methylphenidate to lithium reported five and nine adverse events, respectively. We considered four trials to have notable concerns of vested interests influencing the evidence, and authors from two trials omitted information related to the sources of funding and conflicts of interest.

AUTHORS' CONCLUSIONS

We found no certain evidence that IR methylphenidate compared with placebo or lithium can reduce symptoms of ADHD in adults (low- and very low-certainty evidence). Adults treated with IR methylphenidate are at increased risk of gastrointestinal and metabolic-related harms compared with placebo. Clinicians should consider whether it is appropriate to prescribe IR methylphenidate, given its limited efficacy and increased risk of harms. Future RCTs should explore the long-term efficacy and risks of IR methylphenidate, and the influence of conflicts of interest on reported effects.

Prevalence and Risk Factors Associated With Attention-Deficit/Hyperactivity Disorder Among US Black Individuals: A Systematic Review and Meta-analysis

IMPORTANCE

As stated in the DSM-5, it is generally reported that the prevalence of attention-deficit/hyperactivity disorder (ADHD) is lower among Black individuals compared with the general population. However, Black individuals living in countries where they are considered a minority population group (eg, in Northern America and Europe) are underrepresented in studies evaluating ADHD.

OBJECTIVE

To estimate the pooled prevalence of ADHD and identify associated risk factors among US Black individuals.

DATA SOURCES

This systematic review and meta-analysis identified peer-reviewed studies published until October 18, 2019, using the APA PsycInfo, MEDLINE, Embase, Cochrane CENTRAL, CINAHL, ERIC, and Education Source databases.

STUDY SELECTION

Eligible trials were published in French or English, had empirical data on the prevalence of ADHD in samples or subsamples of Black people, and were conducted in countries with Black minority populations. All studies were assessed and passed quality evaluation.

DATA EXTRACTION AND SYNTHESIS

The PRISMA guideline was used for extracting and reporting data. Random-effects meta-analyses were generated to estimate the prevalence of ADHD among Black individuals using the metafor package in R.

MAIN OUTCOMES AND MEASURES

Prevalence and risk factors associated with ADHD among Black individuals were identified.

RESULTS

A total of 24 independent samples and subsamples from 21 studies published between 1979 and 2020 (154 818 Black participants) were included in this systematic review and meta-analysis. All included studies were conducted in the US. Two studies were conducted assessing adults (aged 18 years or older), 8 assessing children (0-12 years), 1 assessing adolescents (aged 13-17 years), and 13 assessing both children and adolescents. The pooled prevalence of ADHD was 14.54% (95% CI, 10.64%-19.56%). In a narrative review of the studies in this analysis, some studies found risk factors associated with ADHD, such as sociodemographic characteristics (age, sex, race, and socioeconomic status), familial factors, environmental factors, and risk behaviors, but the data did not permit a moderation analysis to assess these findings in this study.

CONCLUSIONS AND RELEVANCE

Contrary to what is stated in the DSM-5, the results of this systematic review and meta-analysis suggest that Black individuals are at higher risk for ADHD diagnoses than the general US population. These results highlight a need to increase ADHD assessment and monitoring among Black individuals from different social backgrounds. They also higlight the importance of establishing accurate diagnoses and culturally appropriate care.

Pharmacogenomic Biomarkers and Their Applications in Psychiatry

Realizing the promise of precision medicine in psychiatry is a laudable and beneficial endeavor, since it should markedly reduce morbidity and mortality and, in effect, alleviate the economic and social burden of psychiatric disorders. This review aims to summarize important issues on pharmacogenomics in psychiatry that have laid the foundation towards personalized pharmacotherapy and, in a broader sense, precision medicine. We present major pharmacogenomic biomarkers and their applications in a variety of psychiatric disorders, such as depression, attention-deficit/hyperactivity disorder (ADHD), narcolepsy, schizophrenia, and bipolar disorder. In addition, we extend the scope into epilepsy, since antiepileptic drugs are widely used to treat psychiatric disorders, although epilepsy is conventionally considered to be a neurological disorder.

Amphetamine-induced alteration to gaze parameters: A novel conceptual pathway and implications for naturalistic behavior

Amphetamine produces a multiplicity of well-documented end-order biochemical, pharmacological and biobehavioural effects. Mechanistically, amphetamine downregulates presynaptic and postsynaptic striatal monoamine (primarily dopaminergic) systems, producing alterations to key brain regions which manifest as stereotyped ridged behaviour which occurs under both acute and chronic dosing schedules and persists beyond detoxification. Despite evidence of amphetamine-induced visual attentional dysfunction, no conceptual synthesis has yet captured how characteristic pharmaco-behavioural processes are critically implicated via these pathways, nor described the potential implications for safety-sensitive behaviours. Drawing on known pathomechanisms, we propose a cross-disciplinary, novel conceptual functional system framework for delineating the biobehavioural consequences of amphetamine use on visual attentional capacity and discuss the implications for functional and behavioural outcomes. Specifically, we highlight the manifest implications for behaviours that are conceptually driven and highly dependent on visual information processing for timely execution of visually-guided movements. Following this, we highlight the potential impact on safety-sensitive, but common behaviours, such as driving a motor vehicle. The close pathophysiological relationship between oculomotor control and higher-order cognitive processes further suggests that dynamic measurement of movement related to the motion of the eye (gaze behaviour) may be a simple, effective and direct measure of behavioural performance capabilities in naturalistic settings. Consequently, we discuss the potential efficacy of ocular monitoring for the detection and monitoring of driver states for this drug user group, and potential wider application. Significance statement: We propose a novel biochemical-physiological-behavioural pathway which delineates how amphetamine use critically alters oculomotor function, visual-attentional performance and information processing capabilities. Given the manifest implications for behaviours that are conceptually driven and highly dependent on these processes, we recommend oculography as a novel means of detecting and monitoring gaze behaviours during naturalistic tasks such as driving. Real-word examination of gaze behaviour therefore present as an effective means to detect driver impairment and prevent performance degradation due to these drugs.

Tai Chi training for attention deficit hyperactivity disorder: A feasibility trial in college students

OBJECTIVE

Many young adults are affected by attention deficit hyperactivity disorder (ADHD) and often desire non-pharmacological treatment options. Mind-body techniques might serve as complementary therapies to first-line stimulant medications, but studies are limited. Tai Chi is an increasingly popular practice that integrates movement with cognitive skills relevant to ADHD. We performed a feasibility trial of Tai Chi training in undergraduates to inform the design of a fully powered randomized controlled trial (RCT).

METHOD

Undergraduates with ADHD were recruited, screened, enrolled, and assessed at baseline. They were assigned to three parallel seven-week intervention arms, Tai Chi, Active Control (cardio-aerobic fitness), and Inactive Control (no contact), with follow-up assessments. Feasibility of a larger clinical trial was evaluated, especially with respect to enrollment and retention. Additionally, potential clinical outcome measures were examined for practicality and reliability.

RESULTS

21 participants were assessed at baseline and 19 at follow-up (90 % retention). The primary clinical outcome measure, self-reported inattention symptoms (Conners' CAARS-S:L DSM-IV Inattentive Symptoms subscale), exhibited good test-retest reliability in controls (r = 0.87, n = 10) and correlated with reduced mindfulness (FFMQ acting with awareness subscale) at baseline (r = -0.74, n = 20). Class attendance and self-reported daily practice time were variable. Randomization to group classes was hindered by the college students' restricted schedules.

CONCLUSION

The high retention rate and good data quality suggest that an RCT of Tai Chi for ADHD is feasible. Further measures are identified to improve enrollment rates, adherence, and randomization procedures. Future work might extend to other young adult populations and high school students.

Effects of a synbiotic on symptoms, and daily functioning in attention deficit hyperactivity disorder - A double-blind randomized controlled trial

Some prebiotics and probiotics have been proposed to improve psychiatric symptoms in children with autism. However, few studies were placebo-controlled, and there is no study on persons with an attention deficit hyperactivity disorder (ADHD) diagnosis. Our aim was to study effects of Synbiotic 2000 on psychiatric symptoms and functioning in children and adults with ADHD without an autism diagnosis. Children and adults (n = 182) with an ADHD diagnosis completed the nine weeks randomized double-blind parallel placebo-controlled trial examining effects of Synbiotic 2000 on the primary endpoints ADHD symptoms, autism symptoms and daily functioning, and the secondary endpoint emotion regulation, measured using the questionnaires SNAP-IV, ASRS, WFIRS, SCQ, AQ and DERS-16. Levels at baseline of plasma C-reactive protein and soluble vascular cell adhesion molecule-1 (sVCAM-1), central to leukocyte-endothelial cell adhesion facilitating inflammatory responses in tissues, were measured using Meso Scale Discovery. Synbiotic 2000 and placebo improved ADHD symptoms equally well, and neither active treatment nor placebo had any statistically significant effect on functioning or sub-diagnostic autism symptoms. However, Synbiotic 2000, specifically, reduced sub-diagnostic autism symptoms in the domain restricted, repetitive and stereotyped behaviors in children, and improved emotion regulation in the domain of goal-directed behavior in adults. In children with elevated sVCAM-1 levels at baseline as well as in children without ADHD medication, Synbiotic 2000 reduced both the total score of autism symptoms, and the restricted, repetitive and stereotyped behaviors. In adults with elevated sVCAM-1 at baseline, Synbiotic 2000 significantly improved emotion regulation, both the total score and four of the five subdomains. To conclude, while no definite Synbiotic 2000-specific effect was detected, the analysis of those with elevated plasma sVCAM-1 levels proposed a reduction of autism symptoms in children and an improvement of emotion regulation in adults with ADHD. Trial registration number: ISRCTN57795429.

[Pharmacotherapy of attention deficit hyperactivity disorder in adults]

Pharmacotherapy is a central component in the context of an overall therapeutic concept in the treatment of adults with attention deficit hyperactivity disorder (ADHD). In this concept psychosocial interventions with psychoeducation or specific psychotherapy measures also play an important role. In adults three compounds are currently approved for the pharmacological treatment of ADHD in Germany. The long-acting stimulants retarded methylphenidate preparations and lisdexamfetamine can be prescribed. Alternatively, the adrenergic uptake inhibitor atomoxetine can be used. In several meta-analyses good effectiveness and tolerance of these drugs on ADHD psychopathology has been shown. They also improve ADHD-related disorders of emotional regulation capability and disorganization in everyday life. Importantly, an improvement in everyday functionality and quality of life under medication could also be shown in several studies. In this review the evidence for pharmacotherapy of ADHD and its implementation into treatment of adult patients is presented.

Signal Transduction of Improving Effects of Ibudilast on Methamphetamine Induced Cell Death

Objective:

Interaction of methamphetamine and sigma (σ) receptors lead to up-regulation and activation of these receptors. The σ receptors induced apoptosis in some parts of the brain by increasing calcium, dopamine, ROS, mitochondrial pores and caspase activity. Ibudilast is a phosphodiesterase inhibitor and anti-inflammatory drug, which can decrease the inflammatory cytokines. Also, it has a neuroprotective effect. It seems that ibudilast can reduce the methamphetamine-induced cell death due to inhibition of σ receptors.

Materials and Methods:

There were seven treatments including; control: culture medium, Treatment 1: 1mM methamphetamine, Treatment 2: 1mM methamphetamine and 1nM ibudilast, Treatment 3: 1mM methamphetamine and 10nM ibudilast, Treatment 4: 1mM methamphetamine and 100nM ibudilast, Treatment 5: 1mM methamphetamine and 1uM ibudilast, Treatment 6: 1mM methamphetamine and 10uM ibudilast, and Treatment 7: 1mM methamphetamine and 100uM ibudilast. Finally, for inhibition of PKA, CREB, IP3 receptor, NMDA receptor, Sigma receptor antagonist, sigma receptor agonist, cells were preincubated with adding H89 dihydrochloride, 666-15, Heparin, Ketamine, BMY 14802, and Pentazocine. MTT and LDH tests were performed for cell viability and cytotoxicity measurement, respectively. In continuing, the caspase activity colorimetric assay kit used for caspase 3 activity diagnosis. Rhodamine-123 performed to detection of mitochondrial membrane potential. TUNEL test used to DNA fragmentation and apoptosis, Fura-2 used to Measurement of (Ca²⁺) ic and (Ca²⁺) m, and fluorescence microscope used to Measurement of antioxidant enzyme activities.

Results:

Ibudilast increased the cell viability and the rhodamine-123 absorbance in methamphetamin-treated PC1₂ cells. It reduced cell cytotoxicity, caspase 3 activity, ic and m Ca²⁺ concentration, (OH) generation and DNA fragmentation in all concentrations of 1 nM t0 100 µM (p<0.05) by the optimal concentration of 100 µM, between our tested treatments.

Conclusion:

Ibudilast as a phosphodiesterase inhibitor can reduce the methamphetamine-induced cell death due to inhibition of σ receptors through cAMP production.

Appraisal of clinical practice guidelines for the management of attention deficit hyperactivity disorder (ADHD) using the AGREE II Instrument: A systematic review

BACKGROUND AND OBJECTIVE

High quality evidence-based clinical practice guidelines (CPGs) have a major impact on the appropriate diagnosis and management and positive outcomes. The evidence-based healthcare for patients with attention deficit hyperactive disorder (ADHD) is challenging. The objective of this study was to appraise the quality of published CPGs for ADHD.

METHODS

A systematic review was conducted for ADHD CPGs using CPG databases, DynaMed, PubMed, and Google Scholar. The quality of each included CPG was appraised by three independent appraisers using the Appraisal of Guidelines for Research & Evaluation II (AGREE II) instrument.

RESULTS

Six CPGs were critically reviewed. The AGREE II standardized domain scores revealed variation between the quality of these CPGs with the National Institute of Health and Care Excellence (NICE), University of Michigan Health System, and American Academy of Pediatrics CPGs as the top three. Overall, the recommendations for management of ADHD were similar in these CPGs.

CONCLUSIONS

Reporting of CPG development is often poorly documented. Guideline development groups should aim to follow the AGREE II criteria to improve the standards and quality of CPGs. The NICE CPG showed the best quality. Embedding the AGREE II appraisal of CPGs in the training and education of healthcare providers is recommended. The protocol for this study was published in PROSPERO (International prospective register of systematic reviews). Link: http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42017078712 and is additionally available from protocols.io. Link: https://dx.doi.org/10.17504/protocols.io.q27dyhn.

Protective potential of Vitamin E against methylphenidate-induced male gonadal changes in albino rats

OBJECTIVE

Attention deficit hyperactivity disorder ranks among the top neuropsychiatric disorder of childhood and adolescents. Methylphenidate (MPH) is the most frequently used pharmacologic agent to treat this condition. Its long-term use has been associated with many unwanted and adverse effects on many organs including male gonads, but so far no study has been done to find out a protective agent. This study investigated the protective potential of Vitamin E (Vit E) against the microscopic and morphometric alterations in male gonads induced by MPH, using albino rats.

METHODS

Adult male albino rats were assigned into three equal groups including one control and two experimental groups. Experimental groups administered with MPH (10 mg/kg) and MPH (10 mg/kg) + Vit E orally (50 mg/kg), daily for 40 days. Testes of the sacrificed animals were removed, processed, and stained with hematoxylin and eosin for examining the microscopic and morphometric alterations and protective potential of Vit E. Data were analyzed using ANOVA.

RESULTS

Experimental animals treated with MPH showed a significant decrease in the diameter of seminiferous tubules (296.86 ± 14.70 µm) and height of germinal epithelium (51.73 ± 3.15 µm) with a corresponding gain in the thickness of the interstitium (47.05 ± 4.94 µm). Animals treated with MPH + Vit E did not reveal any significant testicular microscopic changes and seminiferous tubular alterations induced by MPH.

CONCLUSION

Vit E demonstrated a protective potential against the adverse changes induced by MPH in the male gonads in albino rats.

Long-term deficits in risky decision-making after traumatic brain injury on a rat analog of the Iowa gambling task

Traumatic brain injury (TBI) affects 2.8 million people annually in the United States, with significant populations suffering from ongoing cognitive dysfunction. Impairments in decision-making can have major implications for patients and their caregivers, often enduring for years to decades, yet are rarely explored in experimental TBI. In the current study, the Rodent Gambling Task (RGT), an Iowa Gambling Task analog, was used to assess risk-based decision-making and motor impulsivity after TBI. During testing, rats chose between options associated with different probabilities of reinforcement (sucrose) or punishment (timeout). To determine effects of TBI on learned behaviors versus the learning process, rats were trained either before, or after, a bilateral frontal controlled cortical impact TBI, and then assessed for 12 weeks. To evaluate the degree to which monoamine systems, such as dopamine, were affected by TBI, rats were given an amphetamine challenge, and behavior recorded. Injury immediately and chronically decreased optimal decision-making, and biased rats towards both riskier, and safer (but suboptimal) choices, regardless of prior learning history. TBI also increased motor impulsivity across time, reflecting ongoing neural changes. Despite these similarities in trained and acquisition rats, those that learned the task after injury demonstrated reduced effects of amphetamine on optimal decision-making, suggesting a lesser role of monoamines in post-injury learning. Amphetamine also dose-dependently reduced motor impulsivity in injured rats. This study opens up the investigation of psychiatric-like dysfunction in animal models of TBI and tasks such as the RGT will be useful in identifying therapeutics for the chronic post-injury period.