Double-blind placebo-controlled trial of methylphenidate in the treatment of adult ADHD patients with comorbid cocaine dependence

Treatment of Adolescents with Concurrent Substance Use Disorder and Attention-Deficit/Hyperactivity Disorder: A Systematic Review

Childhood attention-deficit/hyperactivity disorder (ADHD) is a risk factor for the development of substance abuse and substance use disorders (SUD) in adolescence and (early) adulthood. ADHD and SUD also frequently co-occur in treatment-seeking adolescents, which complicates diagnosis and treatment, and is associated with poor treatment outcomes. In this study, we provide a systematic review of controlled studies on the effectiveness of pharmacological, psychosocial, and complementary treatments of ADHD in adolescents with and without comorbid SUD. In addition, we review the longitudinal association between pharmacotherapy for childhood ADHD and the development of SUD in adolescence and early adulthood. We conducted a systematic review of the research literature published since 2000 using Medline, PsycINFO, and the Cochrane Database of Systematic Reviews databases to select randomized clinical trials, observational studies, and meta-analyses. The quality of the evidence from each study was rated using the SIGN grading system. Based on the limited evidence available, strong clinical recommendations are not justified, but provisionally, we conclude that stimulant treatment in children with ADHD may prevent the development of SUD in adolescence or young adulthood, that high-dose stimulant treatment could be an effective treatment for adolescents with ADHD and SUD comorbidity, that cognitive behavior therapy might have a small beneficial effect in these patients, and that alternative treatments are probably not effective. More studies are needed to draw definitive conclusions that will allow for strong clinical recommendations.

Open-label pilot study of lisdexamfetamine for cocaine use disorder

Background: Cocaine use disorder (CUD) is a substantial public health problem with no FDA-approved medication treatments. Psychostimulants have shown promise as pharmacotherapy for CUD. Lisdexamfetamine, a novel prodrug psychostimulant, is roughly 40-50% as potent as dextroamphetamine.Objectives: To evaluate the safety, tolerability, and optimal dosing of lisdexamfetamine for treating CUD.Methods: Open-label, 8-week trial of 17 CUD adults. Participants were titrated to the maximum tolerated dose of 140 mg over 2-week period and maintained for 4 weeks, followed by a two-week taper period. The primary outcome measures were the maximum daily dose achieved during the study period and tolerability as measured by medication-related study drop-out.Results: Among the 16 participants with post-enrollment data, the mean dose of lisdexamfetamine achieved was 118.1 mg (standard deviation (SD) = 40.4), mean retention was 6.5 weeks (SD = 2.0), and no participants discontinued study medication due to adverse effects. Four participants had dose reductions due to adverse effects and continued in the trial. Six participants (37.5%) were abstinent for the last 3 weeks of their study participation. Mean dollars of cocaine spent per day significantly decreased from $19.72 at baseline to $7.57 during the last 3 weeks of study participation (t₁₅ = 3.60, p = .003). The mean percent of using days significantly decreased from 25% at baseline to 12% during the last 3 weeks of study participation (t₁₅ = 3.33, p = .005).Conclusion: The use of lisdexamfetamine for CUD in doses ranging to 140 mg daily was safe and generally well tolerated.

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.

Are non-abstinent reductions in World Health Organization drinking risk level a valid treatment target for alcohol use disorders in adolescents with ADHD?

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Changes in WHO alcohol risk level are highly variable in youth treated for ADHD/SUD.

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Achieving > 2-level reduction in WHO risk is linked to improvements in functioning.

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Achieving > 2-level reduction in WHO risk is linked to decreased ADHD symptoms.

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> 2-level reduction in WHO risk may be a valid non-abstinent AUD outcome in youth with ADHD/SUD.

Introduction

Abstinence from drinking represents the primary treatment target for alcohol use disorders (AUD) in youth, but few adolescents who engage in problematic drinking seek treatment. A reduction in World Health Organization (WHO) drinking risk level has been established as valid and reliable non-abstinent treatment target for AUD in adults but remains unstudied in youth.

Methods

The present study used data from the NIDA-CTN-0028 trial to examine associations between reductions in WHO drinking risk level and changes in global functioning and attention-deficit hyperactivity disorder (ADHD) symptoms during treatment in a sample of adolescents (ages 13–18 years) with ADHD and comorbid substance use disorder (SUD) (n = 297, 61% with AUD) receiving a 16-week intervention that combined ADHD pharmacotherapy (OROS-methylphenidate vs. placebo) and drug-focused cognitive-behavioral therapy.

Results

Shifts in drinking risk level during treatment were highly variable in adolescents treated for ADHD/SUD, and influenced by AUD diagnostic status. In the total sample, 15% of participants had a 2-level or greater reduction in WHO drinking risk level, with 59% and 24% showing no change or an increase in risk-level during treatment respectively. Achieving at least a 2-level change in WHO drinking risk level during treatment was associated with greater reduction in ADHD symptoms and better functional outcomes.

Conclusions

These findings parallel the adult AUD literature and provide preliminary support for the use 2-level reductions in WHO risk levels for alcohol use as a clinically valid non-abstinent treatment outcome for youth with ADHD and comorbid AUD.

Remarkable Reduction of Cocaine Use in Dual Disorder (Adult Attention Deficit Hyperactive Disorder/Cocaine Use Disorder) Patients Treated with Medications for ADHD

Background: Cocaine use disorder (CUD) is a growing public health concern, but so far no effective pharmacotherapies have been demonstrated. Stimulant medications have proved to be promising in CUD treatment. The self-medication hypothesis (SMH) can help to explain this phenomenon better, especially in cases where CUD co-occurs with adult attention deficit hyperactivity disorder (A-ADHD). Methods: In the present retrospective study, a sample of 20 consecutive patients (aged from 18 to 65 years) with dual disorder (A-ADHD/CUD), under treatment with methylphenidate (MPH) or atomoxetine (ATM) medications, was followed to study the effects of A-ADHD treatment on cocaine use. Patients were followed for a mean period of 7 months (minimum 1, maximum 30 months). All individuals were assessed with standardized questionnaires to evaluate diagnosis, treatment efficacy, and clinical improvement. Results: the results showed that behaviors reflecting cocaine addiction were sharply reduced during the stimulant treatment of A-ADHD, and were not correlated with age, gender, familiarity, length of treatment, or medication used. CUD improvement was closely correlated with the A-ADHD improvement. This study supports the validity of the SMH in ADHD patients with co-occurring CUD.

Regulation of the Dopamine and Vesicular Monoamine Transporters: Pharmacological Targets and Implications for Disease

Dopamine (DA) plays a well recognized role in a variety of physiologic functions such as movement, cognition, mood, and reward. Consequently, many human disorders are due, in part, to dysfunctional dopaminergic systems, including Parkinson's disease, attention deficit hyperactivity disorder, and substance abuse. Drugs that modify the DA system are clinically effective in treating symptoms of these diseases or are involved in their manifestation, implicating DA in their etiology. DA signaling and distribution are primarily modulated by the DA transporter (DAT) and by vesicular monoamine transporter (VMAT)-2, which transport DA into presynaptic terminals and synaptic vesicles, respectively. These transporters are regulated by complex processes such as phosphorylation, protein-protein interactions, and changes in intracellular localization. This review provides an overview of 1) the current understanding of DAT and VMAT2 neurobiology, including discussion of studies ranging from those conducted in vitro to those involving human subjects; 2) the role of these transporters in disease and how these transporters are affected by disease; and 3) and how selected drugs alter the function and expression of these transporters. Understanding the regulatory processes and the pathologic consequences of DAT and VMAT2 dysfunction underlies the evolution of therapeutic development for the treatment of DA-related disorders.

Psychotic Symptoms Associated with the use of Dopaminergic Drugs, in Patients with Cocaine Dependence or Abuse

BACKGROUND

In the field of dual diagnosis, physicians are frequently presented with pharmacological questions. Questions about the risk of developing psychotic symptoms in cocaine users who need treatment with dopaminergic drugs could lead to an undertreatment.

OBJECTIVE

Review the presence of psychotic symptoms in patients with cocaine abuse/dependence, in treatment with dopaminergic drugs.

METHODS

Systematic PubMed searches were conducted including December 2014, using the keywords: "cocaine", dopaminergic drug ("disulfuram-methylphenidate-bupropion-bromocriptine-sibutramineapomorphine- caffeine") and ("psychosis-psychotic symptoms-delusional-paranoia"). Articles in English, Spanish, Portuguese, French, and Italian were included. Articles in which there was no history of cocaine abuse/dependence, absence of psychotic symptoms, systematic reviews, and animal studies, were excluded.

RESULTS

313 papers were reviewed. 7 articles fulfilled the inclusion-exclusion criteria. There is a clinical trial including 8 cocaine-dependent patients using disulfiram in which 3 of them presented psychotic symptoms and 6 case-reports: disulfuram (1), methylphenidate (1), disulfiram with methylphenidate (2), and bupropion (2), reporting psychotic symptoms, especially delusions of reference and persecutory ideation.

CONCLUSION

Few cases have been described, which suggests that the appearance of these symptoms is infrequent. The synergy of dopaminergic effects or the dopaminergic sensitization in chronic consumption are the explanatory theories proposed by the authors. In these cases, a relationship was found between taking these drugs and the appearance of psychotic symptoms. Given the low number of studies found, further research is required. The risk of psychotic symptoms seems to be acceptable if we compare it with the benefits for the patients but a closer monitoring seems to be advisable.

Clinical potential of methylphenidate in the treatment of cocaine addiction: a review of the current evidence

Background

Cocaine use continues to be a public health problem, yet there is no proven effective pharmacotherapy for cocaine dependence. A promising approach to treating cocaine dependence may be agonist-replacement therapy, which is already used effectively in the treatment of opioid and tobacco dependence. The replacement approach for cocaine dependence posits that administration of a long-acting stimulant medication should normalize the neurochemical and behavioral perturbations resulting from chronic cocaine use. One potential medication to be substituted for cocaine is methylphenidate (MPH), as this stimulant possesses pharmacobehavioral properties similar to those of cocaine.

Aim

To provide a qualitative review addressing the rationale for the use of MPH as a cocaine substitute and its clinical potential in the treatment of cocaine dependence.

Methods

We searched MEDLINE for clinical studies using MPH in patients with cocaine abuse/dependence and screened the bibliographies of the articles found for pertinent literature.

Results

MPH, like cocaine, increases synaptic dopamine by inhibiting dopamine reuptake. The discriminative properties, reinforcing potential, and subjective effects of MPH and cocaine are almost identical and, importantly, MPH has been found to substitute for cocaine in animals and human volunteers under laboratory conditions. When taken orally in therapeutic doses, its abuse liability, however, appears low, which is especially true for extended-release MPH preparations. Though there are promising data in the literature, mainly from case reports and open-label studies, the results of randomized controlled trials have been disappointing so far and do not corroborate the use of MPH as a substitute for cocaine dependence in patients without attention deficit hyperactivity disorder.

Conclusion

Clinical studies evaluating MPH substitution for cocaine dependence have provided inconsistent findings. However, the negative findings may be explained by specific study characteristics, among them dosing, duration of treatment, or sample size. This needs to be considered when discussing the potential of MPH as replacement therapy for cocaine dependence. Finally, based on the results, we suggest possible directions for future research.

Future pharmacological treatments for substance use disorders

Substance use disorders represent a serious public health and social issue worldwide. Recent advances in our understanding of the neurobiological basis of the addictive processes have led to the development of a growing number of pharmacological agents to treat addictions. Despite this progress, there are no approved pharmacological treatments for cocaine, methamphetamine and cannabis addiction. Moving treatment development to the next stage will require novel ways of approaching substance use disorders. One such novel approach is to target individual vulnerabilities, such as cognitive function, sex differences and psychiatric comorbidities. This review provides a summary of promising pharmacotherapies for alcohol, opiate, stimulant and nicotine addictions. Many medications that target positive and negative reinforcement of drugs, as well as individual vulnerabilities to addiction, are in different phases of development. Clinical trials testing the efficacy of these medications for substance use disorder are warranted.

Pharmacological and clinical dilemmas of prescribing in co-morbid adult attention-deficit/hyperactivity disorder and addiction

The present article reviews whether available efficacy and safety data support the pharmacological treatment of adult attention-deficit/hyperactivity disorder (ADHD) in patients with concurrent substance use disorders (SUD). Arguments for and against treating adult ADHD with active SUD are discussed. Findings from 19 large open studies and controlled clinical trials show that the use of atomoxetine or extended-release methylphenidate formulations, together with psychological therapy, yield promising though inconclusive results about short term efficacy of these drugs in the treatment of adult ADHD in patients with SUD and no other severe mental disorders. However, the efficacy of these drugs is scant or lacking for treating concurrent SUD. No serious safety issues have been associated with these drugs in patients with co-morbid SUD-ADHD, given their low risk of abuse and favourable side effect and drug-drug interaction profile. The decision to treat adult ADHD in the context of active SUD depends on various factors, some directly related to SUD-ADHD co-morbidity (e.g. degree of diagnostic uncertainty for ADHD) and other factors related to the clinical expertise of the medical staff and availability of adequate resources (e.g. the means to monitor compliance with pharmacological treatment). Our recommendation is that clinical decisions be individualized and based on a careful analysis of the advantages and disadvantages of pharmacological treatment for ADHD on a case-by-case basis in the context of active SUD.

Agonist replacement for stimulant dependence: a review of clinical research

Stimulant use disorders are an unrelenting public health concern worldwide. Agonist replacement therapy is among the most effective strategies for managing substance use disorders including nicotine and opioid dependence. The present paper reviewed clinical data from human laboratory self-administration studies and clinical trials to determine whether agonist replacement therapy is a viable strategy for managing cocaine and/or amphetamine use disorders. The extant literature suggests that agonist replacement therapy may be effective for managing stimulant use disorders, however, the clinical selection of an agonist replacement medication likely needs to be based on the pharmacological mechanism of the medication and the stimulant abused by patients. Specifically, dopamine releasers appear most effective for reducing cocaine use whereas dopamine reuptake inhibitors appear most effective for reducing amphetamine use.

Pharmacotherapeutics for substance-use disorders: a focus on dopaminergic medications

INTRODUCTION

Illicit substance-use is a substantial public health concern, contributing over $150 billion in costs annually to Americans. A complex disease, a substance-use disorder affects neural circuits involved in reinforcement, motivation, learning and memory, and inhibitory control.

AREAS COVERED

The modulatory influence of dopamine in mesocorticolimbic circuits contributes to encoding the primary reinforcing effects of substances and numerous studies suggest that aberrant signaling within these circuits contributes to the development of a substance-use disorder in some individuals. Decades of research focused on the clinical development of medications that directly target dopamine receptors has led to recent studies of agonist-like dopaminergic treatments for stimulant-use disorders and, more recently, cannabis-use disorder. Human studies evaluating the efficacy of dopaminergic agonist-like medications to reduce reinforcing effects and substance-use provide some insight into the design of future pharmacotherapy trials. A search of PubMed using specific brain regions, medications, and/or the terms 'dopamine', 'cognition', 'reinforcement', 'cocaine', 'methamphetamine', 'amphetamine', 'cannabis', 'treatment/pharmacotherapy', 'addiction/abuse/dependence' identified articles relevant to this review.

EXPERT OPINION

Conceptualization of substance-use disorders and their treatment continues to evolve. Current efforts increasingly focus on a strategy fostering combination pharmacotherapies that target multiple neurotransmitter systems.

The self-medication hypothesis and psychostimulant treatment of cocaine dependence: an update

BACKGROUND

Stimulant medications have shown promise as a treatment for cocaine dependence (CD) for several decades, yet these treatments have not been widely studied and substantial barriers to clinical implementation remain. The "Self-Medication Hypothesis," posits that an individual's choice to use a particular substance is to some degree based on the substance's effect on subjective painful affects or unpleasant emotional states which may or may not be associated with a psychiatric disorder.

OBJECTIVES

The Self-Medication Hypothesis remains relevant, particularly when considering the scenario of cocaine dependence, both with and without and co-occurring attention-deficit/hyperactivity disorder (ADHD).

METHODS

Two case studies (N=2) and a review of the relevant literature are provided in this clinical update on psychostimulant treatment of cocaine dependence.

RESULTS

Two case studies are presented in which psychostimulant treatment of cocaine dependence was associated with a good clinical outcome.

DISCUSSION

While the use of psychostimulant medication for the treatment of cocaine dependence is controversial, emerging evidence suggests potential utility for this approach.

CONCLUSIONS

Cocaine use in individuals with CD may represent self-medication, and prescribed psychostimulants may have benefit in restoring dopaminergic function.

SCIENTIFIC SIGNIFICANCE

Psychostimulant treatment of cocaine dependence is consistent with the Self-Meidcation Hypothesis and is deserving of further study.

Effects of chronic methylphenidate on cocaine self-administration under a progressive-ratio schedule of reinforcement in rhesus monkeys

It has been hypothesized that drugs that serve as substrates for dopamine (DA) and norepinephrine (NE) transporters may be more suitable medications for cocaine dependence than drugs that inhibit DA and NE uptake by binding to transporters. Previous studies have shown that the DA/NE releaser d-amphetamine can decrease cocaine self-administration in preclinical and clinical studies. The present study examined the effects of methylphenidate (MPD), a DA uptake inhibitor, for its ability to decrease cocaine self-administration under conditions designed to reflect clinically relevant regimens of cocaine exposure and pharmacotherapy. Each morning, rhesus monkeys pressed a lever to receive food pellets under a fixed-ratio 50 schedule of reinforcement; cocaine was self-administered under a progressive-ratio schedule of reinforcement in the evening. After cocaine (0.003-0.56 mg/kg per injection, i.v.) dose-response curves were determined, self-administration sessions were suspended and MPD (0.003-0.0056 mg/kg per hour, i.v.; or 1.0-9.0 mg/kg p.o., b.i.d.) was administered for several weeks. A cocaine self-administration session was conducted every 7 days. When a MPD dose was reached that either persistently decreased cocaine self-administration or produced disruptive effects, the cocaine dose-effect curve was re-determined. In most cases, MPD treatment either produced behaviorally disruptive effects or increased cocaine self-administration; it took several weeks for these effects to dissipate. These data are consistent with the largely negative results of clinical trials with MPD. In contrast to the positive effects with the monoamine releaser d-amphetamine under identical conditions, these results do not support use of monoamine uptake inhibitors like MPD as a medication for cocaine dependence.

Methylphenidate enhances executive function and optimizes prefrontal function in both health and cocaine addiction

Previous studies have suggested dopamine to be involved in error monitoring/processing, possibly through impact on reinforcement learning. The current study tested whether methylphenidate (MPH), an indirect dopamine agonist, modulates brain and behavioral responses to error, and whether such modulation is more pronounced in cocaine-addicted individuals, in whom dopamine neurotransmission is disrupted. After receiving oral MPH (20 mg) or placebo (counterbalanced), 15 healthy human volunteers and 16 cocaine-addicted individuals completed a task of executive function (the Stroop color word) during functional magnetic resonance imaging (fMRI). During MPH, despite not showing differences on percent accuracy and reaction time, all subjects committed fewer total errors and slowed down more after committing errors, suggestive of more careful responding. In parallel, during MPH all subjects showed reduced dorsal anterior cingulate cortex response to the fMRI contrast error>correct. In the cocaine subjects only, MPH also reduced error>correct activity in the dorsolateral prefrontal cortex (controls instead showed lower error>correct response in this region during placebo). Taken together, MPH modulated dopaminergically innervated prefrontal cortical areas involved in error-related processing, and such modulation was accentuated in the cocaine subjects. These results are consistent with a dopaminergic contribution to error-related processing during a cognitive control task.

Treatment discontinuation with methylphenidate in adults with attention deficit hyperactivity disorder: a meta-analysis of randomized clinical trials

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) in adulthood is increasingly diagnosed and treated. Methylphenidate is frequently advocated as a first-line pharmacological treatment.

PURPOSE

The aim of our study was to compare all-cause discontinuation rate of methylphenidate and its pharmaceutical presentations with placebo in adults with ADHD.

METHODS

This was a systematic review and meta-analysis of randomized controlled trials comparing methylphenidate with placebo in adults with ADHD. All-cause treatment discontinuation was the primary endpoint. The efficacy in reducing ADHD symptoms and safety were the secondary endpoints.

RESULTS

Twelve studies (2,496 patients) met the inclusion criteria. Four racemic methylphenidate and one dexmethylphenidate presentations were investigated. The rate of all-cause treatment discontinuation was greater with methylphenidate than with placebo, but this difference was not statistically significant [odds ratio (OR) 1.19, 95 % confidence interval (95 % CI) 0.82-1.74, P = 0.37, I(2) = 64 %] This finding reached the conventional threshold of statistical significance after one outlier study was excluded (OR 1.44, 95 % CI 1.14-1.82, P = 0.002, I(2) = 0). Methylphenidate was more efficacious than placebo for reducing ADHD symptoms and it was associated with a higher proportion of patients dropping out due to adverse effects.

CONCLUSIONS

Despite reducing ADHD symptoms, methylphenidate showed no advantage over placebo in terms of treatment discontinuation. More attention should be given in the future to the endpoint "all-cause treatment discontinuation" when making regulatory decisions and developing clinical guidelines involving the treatment of ADHD in adulthood.

Substance-use disorders in adolescents and adults with ADHD: focus on treatment

A high prevalence of comorbidity of ADHD and substance-use disorders (SUDs) has been shown in the literature. In this article, the literature for the treatment of adolescents and adults with co-occurring ADHD and SUD is examined. Findings from pharmacotherapy suggest mild improvement in ADHD without demonstrable changes in SUD unless the addiction was stabilized prior to treating the ADHD. No unique adverse effects, worsening of SUD, misuse or diversion of stimulants are reported in the included studies. Treating ADHD pharmacologically in individuals with ADHD plus SUD only has a modest impact on ADHD and SUD that is not observed in controlled trials. Limited data in adults with ADHD and brief abstinence of their SUD showed improvements in both ADHD and SUD with treatment. Further studies of cognitive behavioral therapy, sequencing of therapies and longer term treatment outcomes for groups with ADHD and active SUD are necessary.

Agonist replacement therapy for cocaine dependence: a translational review

Cocaine use disorders are prevalent throughout the world. Agonist replacement therapy is among the most effective strategies for managing substance use disorders including nicotine and opioid dependence. This paper reviews the translational literature, including preclinical experiments, human laboratory studies and clinical trials, to determine whether agonist-replacement therapy is a viable strategy for managing cocaine dependence. Discussion is limited to transporter blockers (i.e., methylphenidate) and releasers (i.e., amphetamine analogs) that are available for use in humans in the hope of impacting clinical research and practice more quickly. The translational review suggests that agonist-replacement therapy, especially monoamine releasers, may be effective for managing cocaine dependence. Future directions for medications development are also discussed because the viability of agonist-replacement therapy for cocaine dependence may hinge on identifying novel compounds or formulations that have less abuse and diversion potential.

Pharmacotherapeutics directed at deficiencies associated with cocaine dependence: focus on dopamine, norepinephrine and glutamate

Much effort has been devoted to research focused on pharmacotherapies for cocaine dependence yet there are no FDA-approved medications for this brain disease. Preclinical models have been essential to defining the central and peripheral effects produced by cocaine. Recent evidence suggests that cocaine exerts its reinforcing effects by acting on multiple neurotransmitter systems within mesocorticolimibic circuitry. Imaging studies in cocaine-dependent individuals have identified deficiencies in dopaminergic signaling primarily localized to corticolimbic areas. In addition to dysregulated striatal dopamine, norepinephrine and glutamate are also altered in cocaine dependence. In this review, we present these brain abnormalities as therapeutic targets for the treatment of cocaine dependence. We then survey promising medications that exert their therapeutic effects by presumably ameliorating these brain deficiencies. Correcting neurochemical deficits in cocaine-dependent individuals improves memory and impulse control, and reduces drug craving that may decrease cocaine use. We hypothesize that using medications aimed at reversing known neurochemical imbalances is likely to be more productive than current approaches. This view is also consistent with treatment paradigms used in neuropsychiatry and general medicine.

Correlates of alcohol use in adults with ADHD and comorbid alcohol use disorders: exploratory analysis of a placebo-controlled trial of atomoxetine

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) and substance use disorder are often comorbid in adults. The effects of ADHD treatment on comorbid alcohol use disorder have not been extensively studied.

OBJECTIVE

To assess correlates of ADHD and alcohol use outcomes in ADHD with comorbid alcohol use disorders, via a post-hoc exploratory subgroup analysis of a previously conducted, randomized, double-blind, placebo-controlled study of recently abstinent adults.

METHODS

Adults who had ADHD and alcohol use disorders and were abstinent for 4-30 days were randomized to daily atomoxetine 25-100 mg (mean final dose = 89.9 mg) or placebo for 12 weeks. Changes in ADHD symptoms from baseline to endpoint were assessed using the ADHD Investigator Symptom Rating Scale (AISRS) total score, alcohol use by the timeline followback method, and alcohol cravings by the Obsessive Compulsive Drinking Scale.

RESULTS

Of 147 subjects receiving atomoxetine (n = 72) or placebo (n = 75) in the primary study, 80 (54%) completed 12 weeks (n = 32 atomoxetine; n = 48 placebo). Improvements in ADHD symptoms on the AISRS correlated significantly with decreases in alcohol cravings (Pearson's r = 0.28; 95% confidence interval [CI] = 0.11-0.43; p = 0.002), and the correlation was most notable with atomoxetine (r = 0.29; CI [0.04 - 0.51]; p = 0.023) rather than with placebo (r = 0.24; CI [0.00-0.46]; p = 0.055). On-treatment drinking levels correlated with AISRS scores (r = 0.12; CI [0.05 -0.19]; p = 0.001). Relapse to alcohol abuse significantly correlated with worse ADHD symptoms on 15 of 18 items of the AISRS in the placebo group (p < 0.05 for each).

CONCLUSIONS

No baseline predictor (other than degree of sobriety) of alcohol use or ADHD outcomes emerged. ADHD symptom improvements correlated significantly with reductions in alcohol cravings, and relapse to alcohol abuse correlated significantly with worsening of most ADHD symptoms in the placebo group, but not in the atomoxetine group. This post-hoc subgroup analysis is of a hypothesis-generating nature, and the generalizability of the findings may be limited by exclusion of adults with common ADHD comorbidities from the base study. Further, prospective clinical trials in larger and more heterogeneous patient populations are warranted to confirm or reject these preliminary associations. TRIAL REGISTRATION (BASE STUDY): ClinicalTrials.gov identifier: NCT00190957.

Performance and subjective effects of diazepam and d-amphetamine in high and low sensation seekers

Although sensation-seeking status is associated with age of initiation and amount of drug use among adolescents, and sensitivity to the behavioral and reinforcing effects of drugs among young adults, it is unclear whether sensation-seeking status among adolescents is predictive of sensitivity to the pharmacological effects of drugs (i.e. abuse potential) as adults. This study examined the acute behavioral effects of oral diazepam and d-amphetamine in young adults, ages 18-21 years, who had consistently scored in the highest or lowest third of their grade-based cohort on a modified Sensation Seeking Scale that was completed annually between ages 10 and 14 years. Healthy participants completed 16 7.5-h test days, with test days separated by a minimum of 48 h. Each day, assessments consisting of computer task performance, verbal report of drug effects, and cardiovascular measures were completed 0, 50, 110, 170, 230, and 290 min after drug administration. Placebo and three active doses of diazepam and d-amphetamine (2.5, 5.0 and 10.0 mg/70 kg) were tested under double-blind conditions according to a randomized-block design. Typical stimulant and sedative effects were obtained with d-amphetamine and diazepam, respectively. Drug effects varied as a function of sensation-seeking status, with magnitude of effects on cardiovascular function, task performance, and report of positive drug effects being greater among high sensation seekers, and report of negative drug effects being greater among low sensation seekers. Adolescents who report high levels of sensation seeking on a consistent basis are more sensitive to pharmacological effects of stimulant and sedative drugs that are associated with abuse potential as young adults.

Atomoxetine Treatment for Cocaine Abuse and Adult Attention-Deficit Hyperactivity Disorder (ADHD): A Preliminary Open Trial

The purpose of this 12-week open trial was to evaluate the potential utility of atomoxetine for the treatment of attention deficit hyperactivity disorder (ADHD) in cocaine-dependent treatment seekers. The sample consisted of 20 participants with all participants meeting DSM-IV-TR criteria for ADHD and cocaine dependence (CD). Using several measures to assess ADHD, there was a significant reduction in ADHD symptoms. There was no significant decrease in cocaine use throughout the trial. Taken together, although cocaine-dependent individuals showed some reduction in ADHD symptoms while receiving atomoxetine, the high drop-out rate and lack of impact on cocaine use may limit its utility in ADHD adults who are currently abusing cocaine.

Treatment of adult ADHD: is current knowledge useful to clinicians?

Psychostimulant drugs have for decades been considered the cornerstone of ADHD treatment. Non-stimulant drugs have also been reported successful. However, many controlled studies exclude patients with comorbidities typical for patients seen in clinical setting. Many patients are also considered non-responders to medication. Current knowledge might not be directly useful to clinicians. The present article reviews the literature on pharmacological and psychotherapeutic treatment in adult ADHD emphasizing comorbidity and other clinically important factors, as well as ADHD specific outcomes. Thirty-three relevant studies of pharmacotherapy and three studies of psychotherapy were included. Most subjects had little current comorbidity, but some studies included subjects with substance use disorder. Significant effect of treatment on ADHD symptoms was found in most studies using pharmacotherapy and all studies of psychotherapy. Both positive and negative effects on comorbid anxiety and depression measures were reported. Pharmacotherapy did not seem to have effect on substance use disorder. Few pharmacotherapy studies conducted any long-term follow-up; two studies that did, found that most subjects had discontinued medication. A clear-cut dose-respons relationship was not substanciated. In conclusion, clinicians have good support for both pharmacological and psychotherapeutic treatment of ADHD in adults, but should take additional measures to deal with comorbidities as well as treatment adherence.

Effects of major depressive disorder and attention-deficit/hyperactivity disorder on the outcome of treatment for cocaine dependence

Co-occurring psychiatric disorders have been associated with poor prognosis among substance-dependent patients, but few studies have examined this association among patients with cocaine dependence (CD). We compared baseline characteristics and treatment outcome between cocaine-dependent patients with major depressive disorder (MDD; n = 66), those with attention-deficit/hyperactivity disorder (ADHD; n = 53), and those with CD without comorbid disorders (CD alone; n = 48) who had been randomized to the placebo arms of clinical trials with venlafaxine, methylphenidate, and gabapentin, respectively. The three groups differed significantly in racial makeup, with more Caucasians and Hispanics among patients with MDD and those with ADHD but more African Americans among those with CD alone. The groups did not differ significantly in treatment retention, with retention rates ranging from 42% to 47%; neither did they differ in the rates of achieving 2 consecutive weeks of urinalysis-confirmed abstinence, with rates ranging from 40% to 50%. Using logistic regression for repeated measures with general estimating equations, modeling the likelihood of a cocaine-positive week over time in treatment, we found the diagnostic group to interact with the baseline level of cocaine use and time. Among cocaine-dependent patients who achieved abstinence at baseline, those with MDD and those with ADHD had better outcome over time as compared with patients with CD alone. However, among patients with cocaine-positive urine specimens at baseline, those with MDD and those with ADHD were associated with poor outcome as compared with patients with CD alone. The findings suggest that diagnosis and treatment of co-occurring disorders such as depression and ADHD may be important components of treatment planning for CD and that the baseline level of cocaine use should be included as a covariate in studies evaluating the impact of such treatment.

Treatment strategies for co-occurring ADHD and substance use disorders

Attention-deficit hyperactivity disorder (ADHD) is a common co-occurring mental disorder among patients with substance use disorders (SUD). Clinicians must be cognizant of the complicated nature of diagnosis and treatment of ADHD when comorbid with SUD. Pharmacotherapy remains the mainstay of treatment for ADHD, although complementary psychotherapeutic approaches have been developed. Psychostimulant medications are the most commonly used medications to treat ADHD, but many clinicians are reluctant to prescribe stimulants to patients with SUD. Recommendations for treatment planning and clinical management for patients with co-occurring ADHD and SUD are discussed.

Drug preferences in illicit drug abusers with a childhood tendency of attention deficit/hyperactivity disorder: a study using the Wender Utah Rating Scale in a Japanese prison

The purpose of this study is to clarify the relationship between childhood tendencies of attention deficit/hyperactivity disorder (AD/HD) and illicit drug abuse in Japanese prisoners, and to clarify whether drug abusers with AD/HD prefer methamphetamine (MAP) more than other illicit drugs. The Japanese version of the Wender Utah Rating Scale (WURS), which is a self-reporting instrument to retrospectively identify childhood tendencies of AD/HD tendencies, was carried given to 413 prisoners without a drug addiction and 282 prisoners with a drug addiction (192, MAP; 53, toluene; and 37, cannabis). WURS scores were compared between prisoners with and without a drug addiction, and between MAP, toluene, and cannabis abusers. Consequently, prisoners with a drug addiction showed significantly higher WURS scores than those without the addiction (P < 0.001). Toluene abusers showed significantly higher WURS scores than cannabis abusers (P < 0.001), and included a higher proportion with scores over cut-off than MAP or cannabis abusers (P = 0.005). In conclusion, a close relationship existed between illicit drug abuse and childhood AD/HD tendencies. Drug-abusing prisoners with AD/HD tendencies were not prone to choose MAP over other illicit drugs.