Modafinil and sleep architecture in an inpatient-outpatient treatment study of cocaine dependence

Modafinil, an atypical CNS stimulant?

Modafinil is a central nervous system stimulant approved for the treatment of narcolepsy and sleep disorders. Due to its wide range of biochemical actions, modafinil has been explored for other potential therapeutic uses. Indeed, it has shown promise as a therapy for cognitive disfunction resulting from neurologic disorders like ADHD, and as a smart drug in non-medical settings. The mechanism(s) of actions underlying the therapeutic efficacy of this agent remains largely elusive. Modafinil is known to inhibit the dopamine transporter, thus decreasing dopamine reuptake following neuronal release, an effect shared by addictive psychostimulants. However, modafinil is unique in that only a few cases of dependence on this drug have been reported, as compared to other psychostimulants. Moreover, modafinil has been tested, with some success, as a potential therapeutic agent to combat psychostimulant and other substance use disorders. Modafinil has additional, but less understood, actions on other neurotransmitter systems (GABA, glutamate, serotonin, norepinephrine, etc.). These interactions, together with its ability to activate selected brain regions, are likely one of the keys to understand its unique pharmacology and therapeutic activity as a CNS stimulant. In this chapter, we outline the pharmacokinetics and pharmacodynamics of modafinil that suggest it has an "atypical" CNS stimulant profile. We also highlight the current approved and off label uses of modafinil, including its beneficial effects as a treatment for sleep disorders, cognitive functions, and substance use disorders.

Sleep-mediated regulation of reward circuits: implications in substance use disorders

Our modern society suffers from both pervasive sleep loss and substance abuse-what may be the indications for sleep on substance use disorders (SUDs), and could sleep contribute to the individual variations in SUDs? Decades of research in sleep as well as in motivated behaviors have laid the foundation for us to begin to answer these questions. This review is intended to critically summarize the circuit, cellular, and molecular mechanisms by which sleep influences reward function, and to reveal critical challenges for future studies. The review also suggests that improving sleep quality may serve as complementary therapeutics for treating SUDs, and that formulating sleep metrics may be useful for predicting individual susceptibility to SUDs and other reward-associated psychiatric diseases.

Rapid Eye Movement Sleep Engages Melanin-Concentrating Hormone Neurons to Reduce Cocaine Seeking

BACKGROUND

Persistent sleep disruptions following withdrawal from abused drugs may hold keys to battle drug relapse. It is posited that there may be sleep signatures that predict relapse propensity, identifying which may open new avenues for treating substance use disorders.

METHODS

We trained male rats (approximately postnatal day 56) to self-administer cocaine. After long-term drug withdrawal (approximately postnatal day 100), we examined the correlations between the intensity of cocaine seeking and key sleep features. To test for causal relationships, we then used behavioral, chemogenetic, or optogenetic methods to selectively increase rapid eye movement sleep (REMS) and measured behavioral and electrophysiological outcomes to probe for cellular and circuit mechanisms underlying REMS-mediated regulation of cocaine seeking.

RESULTS

A selective set of REMS features was preferentially associated with the intensity of cue-induced cocaine seeking after drug withdrawal. Moreover, selectively increasing REMS time and continuity by environmental warming attenuated a withdrawal time-dependent intensification of cocaine seeking, or incubation of cocaine craving, suggesting that REMS may benefit withdrawal. Warming increased the activity of lateral hypothalamic melanin-concentrating hormone (MCH) neurons selectively during prolonged REMS episodes and counteracted cocaine-induced synaptic accumulation of calcium-permeable AMPA receptors in the nucleus accumbens-a critical substrate for incubation. Finally, the warming effects were partly mimicked by chemogenetic or optogenetic stimulations of MCH neurons during sleep, or intra-accumbens infusions of MCH peptide during the rat's inactive phase.

CONCLUSIONS

REMS may encode individual vulnerability to relapse, and MCH neuron activities can be selectively targeted during REMS to reduce drug relapse.

Safety and tolerability of progesterone treatment for women with cocaine use disorder: a pilot treatment trial

Background: Problematic cocaine use remains a significant public health issue, particularly among women. However, no concerted efforts have been made to target a pharmacological treatment option for women with cocaine use disorder (CUD) despite preclinical, human laboratory, and a limited number of clinical studies demonstrating that progesterone can attenuate the effects of cocaine to a greater extent in women than men.Objectives: To evaluate the safety, tolerability, and preliminary efficacy of progesterone for treating women with CUD.Methods: A 10-week double-blind randomized treatment trial was conducted. Prior to randomization, participants were required to achieve cocaine abstinence (1 week) before assignment to progesterone (up to 400 mg/day) or placebo. The primary efficacy outcomes were days to relapse and cocaine abstinence during the last 3 weeks of the trial. The frequency of side effects was also assessed.Results: 227 women were assessed for eligibility. Twenty-five women entered treatment and 21 were randomized to progesterone (n = 11) or placebo (n = 10). The majority of women relapsed in less than 4 days with no differences between the two groups. Further, there were no significant differences between the progesterone and placebo groups in terms of cocaine abstinence during the last 3 weeks of the trial (27% and 10% respectively). The most commonly reported side effects were headache and fatigue, but no group differences were noted.Conclusions: Progesterone was well tolerated and safe and supports further study is in a larger sample to determine if exogenous progesterone is an effective treatment option for women with CUD.(ClinicalTrials.gov Identifier: NCT00632099).

Helpful or Harmful? The Therapeutic Potential of Medications with Varying Degrees of Abuse Liability in the Treatment of Substance Use Disorders

Purpose of Review

This review summarizes recent clinical trial research on pharmacological treatments for substance use disorders, with a specific focus on agents with potential abuse liability.

Recent Findings

Pharmacological treatments for substance use disorders may include gabapentinoids, baclofen, modafinil, ketamine, cannabinoids, gamma-hydroxybutyrate, and psychedelics. Gabapentinoids may decrease negative subjective effects of withdrawal in alcohol and cannabis use disorders. Cannabinoids similarly appear to decrease use and withdrawal symptoms in cannabis use disorder, while research shows stimulant medications may reduce cravings and increase abstinence in cocaine use disorder. Ketamine and psychedelics may help treat multiple substance use disorders. Ketamine may reduce withdrawal symptoms, promote abstinence, and diminish cravings in alcohol and cocaine use disorders and psychedelics may promote remission, decrease use, and reduce cravings in alcohol and opioid use disorders.

Summary

Regardless of current regulatory approval statuses and potentials for abuse, multiple agents should not be dismissed prematurely as possible treatments for substance use disorders. However, further clinical research is needed before effective implementation can begin in practice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40429-022-00432-9.

Objective sleep outcomes in randomized-controlled trials in persons with substance use disorders: A systematic review

BACKGROUND

Improving sleep health is an important target for substance use disorder (SUD) research. However, there is little guidance for SUD researchers regarding the use of technologies to objectively assess sleep outcomes in randomized-controlled trials (RCTs). This systematic review aimed to describe the use of technologies to objectively measure sleep outcomes in RCTs conducted in persons with SUDs, in order to inform future sleep intervention studies in SUD populations.

METHODS

This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) on May 7th, 2020 (CRD42020182004). RCTs were reviewed here if they were peer-reviewed manuscripts that included objective measures of sleep in RCTs that sought to improve sleep in persons with SUDs.

RESULTS

The initial search yielded 13,403 potential articles, with 27 meeting a priori criteria to be included in this review. The most common SUD was alcohol use disorder (59%). The most common technology used to assess sleep was polysomnography (41%), followed by actigraphy (37%), ambulatory polysomnography or components of polysomnography (e.g., electroencephalography; 19%), and at-home sleep apnea testing (7%). The most common sleep outcome reported was total sleep time (96%).

CONCLUSIONS

There are a range of options to assess objective sleep outcomes. Polysomnography or ambulatory devices that directly measure brain activity are critical to advance medications through the regulatory process for the indication of improving sleep duration, continuity, and/or sleep onset latency outcomes. Actigraphy is also useful in preliminary investigations and in detecting the relationship between diurnal and SUD-related behaviors.

Patient-reported sleep outcomes in randomized-controlled trials in persons with substance use disorders: A systematic review

BACKGROUND

Sleep disturbances and disorders are a common and sometimes recalcitrant problem in persons recovering from substance use disorders (SUDs). As such, several randomized-controlled trials (RCTs) have been conducted to address sleep disturbances in a variety of SUD subpopulations and clinical scenarios. The goal of this systematic review was to collate patient-reported sleep outcomes used in past SUD-related RCTs to provide guidance for future sleep research in persons with SUDs.

METHODS

This systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) on May 7th, 2020 (CRD42020182004). Studies were included if they were peer-reviewed manuscripts describing RCTs in an SUD population.

RESULTS

The initial search yielded 13,403 candidate articles, and 76 met a priori criteria and were included in this review. Thirty-five (46.1%) assessed sleep as a primary outcome (i.e., sleep improvement was the primary goal of the research) and 41 (53.9%) assessed sleep as a secondary outcome (i.e., sleep improvement was an important outcome, but not the primary outcome). The most commonly used measures included the Pittsburgh Sleep Quality Index, the Insomnia Severity Index, and sleep diaries. However, multiple additional sleep assessments were also used, including visual analogue and Likert scales.

CONCLUSIONS

The field of addiction medicine would benefit from a streamlined approach in assessing patient-reported sleep in RCTs, including commonly used and validated assessments of sleep quality, inserting daily or repeated measures into RCTs, and including questionnaires that assess clinically relevant insomnia or other sleep disorders.

Modafinil Does Not Reduce Cocaine Use in Methadone-Maintained Individuals

Introduction

There are no approved medications for the treatment of cocaine use disorder (CUD). Modafinil, a cognitive-enhancer with weak stimulant-like effects, has shown promise in initial studies as a treatment for CUD. Its potential efficacy has not been examined in individuals dually dependent on cocaine and opioids.

Methods

This study examined the efficacy of modafinil, in combination with contingency management (CM), for reducing cocaine and opioid use and improving cognitive function in methadone-stabilized individuals with opioid and cocaine dependence. We conducted a 17-week, double-blind, randomized controlled trial in which participants were randomized to one of four conditions: 1) modafinil + CM; 2) modafinil + yoked-control (YC); 3) placebo +CM; or 4) placebo + YC. Additionally, all subjects received platform treatments of cognitive behavioral therapy (CBT) and methadone. While the original planned sample size was N=160, a total of 91 participants were randomized. The two primary cocaine use outcomes were percentage of urine specimens positive for cocaine and percent of days of self-reported abstinence from cocaine during treatment. Cognitive function, opioid use, and secondary cocaine use outcomes were also considered.

Results

Modafinil was well-tolerated with minimal reports of adverse effects. Modafinil was no more effective than placebo in reducing cocaine or opioid use or improving cognitive performance.

Conclusions

In the context of a trial with robust control conditions and platform treatments, findings did not provide support for the efficacy of modafinil treatment for the treatment of CUD in methadone-stabilized individuals with dual opioid and cocaine dependence.

Temporal instability in brain activation: a novel paradigm for evaluating the maintenance of attention among substance dependent patients

RATIONALE

Prior studies have demonstrated statistically significant but subtle differences in brain function between patients with a history of substance dependence (SD) and control groups.

OBJECTIVES

The goal of the present study was to show that variability in brain activation over the trials of a cognitive task is more useful for revealing the putative impact of SD than analyses focusing on the amplitude of activation averaged over trials. The study also tested the additional contribution of antisocial personality disorder (ASPD)-a prevalent comorbidity that promotes both an early onset and more severe course of SD.

METHODS

Two hundred eleven adults performed two selective attention tasks while P300 event-related electroencephalographic potentials were recorded. They were assigned to one of 3 mutually exclusive groups: no lifetime history of SD or ASPD (n = 67), a SD history but no ASPD (n = 68), or both SD and ASPD (n = 76).

RESULTS

The major finding was a statistically significant elevation of P300 amplitude inter-trial variability (ITV) in the SD plus ASPD group in comparison to the group with neither attribute. The elevation was detected during both selective attention tasks and most prominent at electrodes sites located over the frontal brain. There were no group differences in P300 amplitude averaged over trials.

CONCLUSIONS

We conclude from these findings that the ITV of P300 amplitude is an efficient and sensitive biomarker of the maintenance of attention. It is valuable for revealing group differences associated with substance dependence and ASPD. It may ultimately be valuable for detecting improvements resulting from psychostimulant treatment or other interventions, including cognitive remediation.

At the intersection of sleep deficiency and opioid use: mechanisms and therapeutic opportunities

Due to the ongoing opioid epidemic, innovative scientific perspectives and approaches are urgently needed to reduce the unprecedented personal and societal burdens of nonmedical and recreational opioid use. One promising opportunity is to focus on the relationship between sleep deficiency and opioid use. In this review, we examine empirical evidence: (1) at the interface of sleep deficiency and opioid use, including hypothesized bidirectional associations between sleep efficiency and opioid abstinence; (2) as to whether normalization of sleep deficiency might directly or indirectly improve opioid abstinence (and vice versa); and (3) regarding mechanisms that could link improvements in sleep to opioid abstinence. Based on available data, we identify candidate sleep-restorative therapeutic approaches that should be examined in rigorous clinical trials.

Psychostimulant Use Disorder, an Unmet Therapeutic Goal: Can Modafinil Narrow the Gap?

The number of individuals affected by psychostimulant use disorder (PSUD) has increased rapidly over the last few decades resulting in economic, emotional, and physical burdens on our society. Further compounding this issue is the current lack of clinically approved medications to treat this disorder. The dopamine transporter (DAT) is a common target of psychostimulant actions related to their use and dependence, and the recent availability of atypical DAT inhibitors as a potential therapeutic option has garnered popularity in this research field. Modafinil (MOD), which is approved for clinical use for the treatment of narcolepsy and sleep disorders, blocks DAT just like commonly abused psychostimulants. However, preclinical and clinical studies have shown that it lacks the addictive properties (in both behavioral and neurochemical studies) associated with other abused DAT inhibitors. Clinical availability of MOD has facilitated its off-label use for several psychiatric disorders related to alteration of brain dopamine (DA) systems, including PSUD. In this review, we highlight clinical and preclinical research on MOD and its R-enantiomer, R-MOD, as potential medications for PSUD. Given the complexity of PSUD, we have also reported the effects of MOD on psychostimulant-induced appearance of several symptoms that could intensify the severity of the disease (i.e., sleep disorders and impairment of cognitive functions), besides the potential therapeutic effects of MOD on PSUD.

Interaction between cocaine use and sleep behavior: A comprehensive review of cocaine's disrupting influence on sleep behavior and sleep disruptions influence on reward seeking

Dopamine, orexin (hypocretin), and adenosine systems have dual roles in reward and sleep/arousal suggesting possible mechanisms whereby drugs of abuse may influence both reward and sleep/arousal. While considerable variability exists across studies, drugs of abuse such as cocaine induce an acute sleep loss followed by an immediate recovery pattern that is consistent with a normal response to loss of sleep. Under more chronic cocaine exposure conditions, an abnormal recovery pattern is expressed that includes a retention of sleep disturbance under withdrawal and into abstinence conditions. Conversely, experimentally induced sleep disturbance can increase cocaine seeking. Thus, complementary, sleep-related therapeutic approaches may deserve further consideration along with development of non-human models to better characterize sleep disturbance-reward seeking interactions across drug experience.

Sleep and alertness disturbance and substance use disorders: A bi-directional relation

The majority of the literature describing the relation of sleep/alertness disturbance and substance use disorders (SUD) has focused on the disruptive effects of substances with abuse liability on sleep and alertness. Rarely have studies or literature reviews assessed or discussed how sleep/alertness disturbance affects substance use. This paper focuses on the sleep/alertness disturbance side of the relation. We argue that the relation is bi-directional and review evidence showing that sleep/alertness disturbance affects all phases of the addiction cycle, including the initiation, maintenance and relapse of SUD. We review a variety of substances across all phases of the addiction cycle and conclude sleep/alertness disturbance is a critical factor in both understanding and treating SUD.

Modafinil reduces smoked cocaine self-administration in humans: effects vary as a function of cocaine 'priming' and cost

BACKGROUND

The absence of an FDA-approved medication for the treatment of cocaine use disorder (CUD) may, in part, reflect the varying conditions present when the decision to use cocaine is made, with one medication unlikely to work under all conditions. The objective of this double-blind, placebo-controlled, human laboratory study was to test the effects of modafinil, a medication with mixed efficacy for the treatment of CUD, using a novel self-administration procedure designed to model distinct clinical scenarios.

METHODS

During modafinil maintenance (0, 300 mg/day), participants chose to self-administer up to 7 doses of smoked cocaine (25 mg) under 9 conditions: immediately after exposure to: (a) cues associated with cocaine and a non-contingent cocaine administration, i.e. 'prime' (25 mg), (b) only cocaine cues, and (c) neither cues nor cocaine. Each condition was tested when self-administered cocaine cost $5, $10 and $15/dose.

RESULTS

Nontreatment-seeking cocaine smokers (3 F,13 M), spending $388 ± 218/week on cocaine and with no history of alcohol use disorder, completed the study. Relative to placebo, modafinil robustly attenuated self-administration when cocaine was expensive ($10,$15/dose) and when there was no 'prime.' Modafinil had no effect on self-administration when cocaine was inexpensive ($5/dose) or when participants received a 'prime.'

CONCLUSIONS

Modafinil's effects on cocaine-taking varied substantially as a function of recent cocaine exposure and cost, which may help explain the mixed clinical findings. Modafinil may be most effective for preventing relapse in abstinent patients, particularly under conditions in which cocaine is costly, rather than initiating abstinence for those continuing to use cocaine.

The Relevance of Dual Diagnoses among Drug-Dependent Patients with Sleep Disorders

BACKGROUND

Sleep disorders are often associated with drug use. Nearly 70% of patients admitted for detoxification report sleep problems. Dual disorder (DD) is the comorbidity between mental disorders in general and disorders related to psychoactive substance use. The association between substance use and sleep disorders (SD) appears to be bidirectional. Our objective is to analyze the association between sleep disturbance history and drug use pattern (alcohol, cannabis, opioids, and cocaine).

METHODS

Analysis of data in the first interview at the Addictions Unit of the Department of Psychiatry at the University of Salamanca Health Care Complex between October 2017 and January 2020. The sample consists of 398 patients. We studied the association between different variables: origin of patients (Inpatient Dual Diagnosis Detoxification Unit (IDDDU) vs. Outpatient Drug Clinic (ODC), presence of affective disorder, psychotic disorder, type of drug used, and treatment.

RESULTS

Of patients with DD, 62% had more delayed sleep induction, sleep fragmentation, early awakening, and nightmares. Outpatients had more difficulty falling asleep because, in many cases, they had not previously sought any medical assistance. On the other hand, 67% of the patients with insomnia presented depression.

CONCLUSIONS

There is evidence of a harmful association between DD and SD.

Modafinil potentiates cocaine self-administration by a dopamine-independent mechanism: possible involvement of gap junctions

Modafinil and methylphenidate are medications that inhibit the neuronal reuptake of dopamine, a mechanism shared with cocaine. Their use as "smart drugs" by healthy subjects poses health concerns and requires investigation. We show that methylphenidate, but not modafinil, maintained intravenous self-administration in Sprague-Dawley rats similar to cocaine. Both modafinil and methylphenidate pretreatments potentiated cocaine self-administration. Cocaine, at self-administered doses, stimulated mesolimbic dopamine levels. This effect was potentiated by methylphenidate, but not by modafinil pretreatments, indicating dopamine-dependent actions for methylphenidate, but not modafinil. Modafinil is known to facilitate electrotonic neuronal coupling by actions on gap junctions. Carbenoxolone, a gap junction inhibitor, antagonized modafinil, but not methylphenidate potentiation of cocaine self-administration. Our results indicate that modafinil shares mechanisms with cocaine and methylphenidate but has a unique pharmacological profile that includes facilitation of electrotonic coupling and lower abuse liability, which may be exploited in future therapeutic drug design for cocaine use disorder.

Prescription psychostimulants for the treatment of stimulant use disorder: a systematic review and meta-analysis

RATIONALE

Agonist-based pharmacologic intervention is an accepted approach in treatment of opioid and tobacco use disorders.

OBJECTIVES

We conducted a systematic review and meta-analysis to evaluate usefulness of an agonist approach as treatment of (psycho)stimulant use disorder (PSUD).

METHODS

We reviewed PubMed/Medline, LILACS, and ClinicalTrials.gov databases searching for randomized, double-blind, placebo-controlled, parallel-design studies evaluating outcomes of individuals treated for cocaine- or amphetamine-type substance use disorder. We combined results of all trials that included the following prescription psychostimulants (PPs): modafinil, methylphenidate, or amphetamines (mixed amphetamine salts, lisdexamphetamine, and dextroamphetamine). The combined sample consisted of 2889 patients. Outcomes of interest included the following: drug abstinence (defined as 2-3 weeks of sustained abstinence and the average maximum days of consecutive abstinence), percentage of drug-negative urine tests across trial, and retention in treatment. We conducted random-effects meta-analyses and assessed quality of evidence using the GRADE system.

RESULTS

Thirty-eight trials were included. Treatment with PPs increases rates of sustained abstinence [risk ratio (RR) = 1.45, 95% confidence interval (CI) = (1.10, 1.92)] and duration of abstinence [mean difference (MD) = 3.34, 95% CI = (1.06, 5.62)] in patients with PSUD, particularly those with cocaine use disorder (very low-quality evidence). Prescription amphetamines were particularly efficacious in promoting sustained abstinence in patients with cocaine use disorder [RR = 2.44, 95% CI = (1.66, 3.58)], and higher doses of PPs were particularly efficacious for treatment of cocaine use disorder [RR = 1.95, 95% CI = (1.38, 2.77)] (moderate-quality evidence). Treatment with prescription amphetamines also yielded more cocaine-negative urines [MD = 8.37%, 95% CI = (3.75, 12.98)]. There was no effect of PPs on the retention in treatment.

CONCLUSION

Prescription psychostimulants, particularly prescription amphetamines given in robust doses, have a clinically significant beneficial effect to promote abstinence in the treatment of individuals with PSUD, specifically the population with cocaine use disorder.

Sleep quality improves during treatment with repetitive transcranial magnetic stimulation (rTMS) in patients with cocaine use disorder: a retrospective observational study

BACKGROUND

Sleep disturbance is a prominent and common complaint in people with cocaine use disorder (CUD), either during intake or withdrawal. Repetitive transcranial magnetic stimulation (rTMS) has shown promise as a treatment for CUD. Thus, we evaluated the relationship between self-perceived sleep quality and cocaine use pattern variables in outpatients with CUD undergoing an rTMS protocol targeted at the left dorsolateral prefrontal cortex.

METHODS

This is a retrospective observational study including 87 patients diagnosed with CUD according to the DSM-5 criteria. Scores in Pittsburgh Sleep Quality Index (PSQI), Cocaine Craving Questionnaire (CCQ), Beck Depression Inventory-II (BDI-II), Self-rating Anxiety Scale (SAS), and Symptoms checklist 90-Revised (outcome used: Global Severity Index, GSI) were recorded at baseline, and after 5, 30, 60, and 90 days of rTMS treatment. Cocaine use was assessed by self-report and regular urine screens.

RESULTS

Sleep disturbances (PSQI scores > 5) were common in patients at baseline (mean ± SD; PSQI score baseline: 9.24 ± 3.89; PSQI > 5 in 88.5% of patients). PSQI scores significantly improved after rTMS treatment (PSQI score Day 90: 6.12 ± 3.32). Significant and consistent improvements were also seen in craving and in negative-affect symptoms compared to baseline. Considering the lack of a control group, in order to help the conceptualization of the outcomes, we compared the results to a wait-list group (n = 10). No significant improvements were observed in the wait-list group in any of the outcome measures.

CONCLUSIONS

The present findings support the therapeutic role of rTMS interventions for reducing cocaine use and accompanying symptoms such as sleep disturbance and negative-affect symptoms.

TRIAL REGISTRATION

ClinicalTrials.gov.NCT03733821.

Pharmacokinetic and pharmacodynamic of the cognitive enhancer modafinil: Relevant clinical and forensic aspects

Modafinil is a nonamphetamine nootropic drug with an increasingly therapeutic interest due to its different sites of action and behavioral effects in comparison to cocaine or amphetamine. A review of modafinil (and of its prodrug adrafinil and its R-enantiomer armodafinil) chemical, pharmacokinetic, pharmacodynamic, toxicological, clinical and forensic aspects was performed, aiming to better understand possible health problems associated to its unconscious and unruled use. Modafinil is a racemate metabolized mainly in the liver into its inactive acid and sulfone metabolites, which undergo primarily renal excretion. Although not fully clarified, major effects seem to be associated to inhibition of dopamine reuptake and modulation of several other neurochemical pathways, namely noradrenergic, serotoninergic, orexinergic, histaminergic, glutamatergic and GABAergic. Due its wake-promoting effects, modafinil is used for the treatment of daily sleepiness associated to narcolepsy, obstructive sleep apnea and shift work sleep disorder. Its psychotropic and cognitive effects are also attractive in several other pathologies and conditions that affect sleep structure, induce fatigue and lethargy, and impair cognitive abilities. Additionally, in health subjects, including students, modafinil is being used off-label to overcome sleepiness, increase concentration and improve cognitive potential. The most common adverse effects associated to modafinil intake are headache, insomnia, anxiety, diarrhea, dry mouth and raise in blood pressure and heart rate. Infrequently, severe dermatologic effects in children, including maculopapular and morbilliform rash, erythema multiforme and Stevens-Johnson Syndrome have been reported. Intoxication and dependence associated to modafinil are uncommon. Further research on effects and health implications of modafinil and its analogs is steel needed to create evidence-based policies.

The cognitive cost of reducing relapse to cocaine-seeking with mGlu5 allosteric modulators

RATIONALE

Cocaine use disorder (CUD) remains difficult to treat with no FDA-approved medications to reduce relapse. Antagonism of metabotropic glutamate receptor 5 (mGlu5) has been demonstrated to decrease cocaine-seeking but may also further compromise cognitive function in long-term cocaine users.

OBJECTIVES

Here we assessed the effect of repeated administration of negative or positive allosteric modulators (NAM or PAM) of mGlu5 on both cognitive performance and (context+cue)-primed cocaine-seeking after prolonged abstinence (≥ 45 days).

METHODS

Adult male Sprague-Dawley rats underwent 6 days of short-access (1 h/day) and 12 days of long-access (6 h/day) cocaine self-administration. Rats were then trained and tested in a delayed match-to-sample (DMS) task to establish baseline working memory performance over a 5-day block of testing. Next, rats received daily systemic administration of the mGlu5 NAM 3-((2-methyl-1,3-thiazol-4-yl)ethynyl)pyridine hydrochloride (MTEP; 3 mg/kg), the mGlu5 PAM 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB; 30 mg/kg) or vehicle prior to DMS testing during a block of 5 days, followed by a 5-day washout DMS testing block.

RESULTS

MTEP and CDPPB decreased drug-seeking in response to cocaine-associated cues after prolonged abstinence. However, repeated treatment with MTEP impaired working memory, while CDPPB had no effects on performance.

CONCLUSIONS

These results emphasize the relevance of evaluating cognitive function within the context of investigating pharmacotherapies to treat CUD. Further research is needed to determine how two mechanistically different pharmacological compounds can exert the same behavioral effects to reduce cocaine-seeking.

Clinical Trials for Stimulant Use Disorders: Addressing Heterogeneities That May Undermine Treatment Outcomes

In recent years, use of cocaine and amphetamines and deaths associated with stimulants have been on the rise, and there are still no FDA-approved medications for stimulant use disorders. One contributing factor may involve heterogeneity. At the neurobiological level, dual dopamine dysfunction may be undermining medication efficacy, suggesting a need for combination pharmacotherapies. At the population level, individual variability is expressed in a number of ways and, if left unaddressed, may interfere with medication efficacy. This chapter reviews studies investigating medications to address dopamine dysfunction, and it also identifies several prominent heterogeneities associated with stimulant (and other substance) use disorders. The chapter has implications for improving interventions to treat stimulant use disorders, and the theme of individual heterogeneity may have broader application across substance use disorders.

Preliminary examination of the orexin system on relapse-related factors in cocaine use disorder

RATIONALE

Current evidence and literature reviews provide a strong justification for examining the orexin receptor (OXR) system as a therapeutic target in substance use disorders, including cocaine and other psychostimulants.

OBJECTIVES

In this preliminary, proof-of-concept examination of orexin modulation in humans with cocaine use disorder, we measured changes in domains tied to relapse: stress, sleep, cue reactivity, and inhibitory control. Additionally, mood symptoms (anxiety, depression), medication compliance, and side effects were assessed.

METHODS

Twenty non-treatment seeking subjects with cocaine use disorder (CUD) received either the OX₁R / OX₂R antagonist suvorexant PO or placebo at 10 PM daily for two weeks (10 mg week 1, 20 mg week 2). Using psychometrics, smart-watch actigraphy, a cold-pressor stress challenge, and eye-tracking technology, the following domains were examined: sleep, stress/anxiety, cue-reactivity (attentional bias, craving), and inhibitory control. Psychometric data were collected every M/W/F (7 time points). Laboratory data were collected weekly (3 time points).

RESULTS

Bayesian and frequentist generalized linear models were employed in parallel to examine the effects of suvorexant compared to placebo, with a Bayesian posterior probability threshold >80% as evidence of a signal for suvorexant. Notable results favoring suvorexant over placebo included fewer total anti-saccade errors, improved sleep actigraphy (sleep/awake periods), pre/post cold-pressor change in heart rate and salivary cortisol (all posterior probabilities >94%), and craving (posterior probability >87%).

CONCLUSIONS

Initial but restricted evidence is provided supporting the orexin system as a modulator of relapse-related processes in cocaine use disorder. Baseline differences in the main outcome variables were not experimentally controlled and differences in craving were observed at baseline. This, in combination with a limited sample size, constrain the nature of the project. The results may serve to inform more comprehensive future research.

Substance use outcomes in cocaine-dependent tobacco smokers: A mediation analysis exploring the role of sleep disturbance, craving, anxiety, and depression

BACKGROUND

Sleep disturbance may play a role in cocaine use outcomes and, hence, may be a potential therapeutic target for cocaine use disorder (CUD). Research in this area, which has largely relied on resource-intensive polysomnography, would be facilitated by identifying a self-report sleep measure predictive of CUD outcomes and by a better understanding of the mechanisms by which sleep may impact CUD outcomes. This study tested the predictive validity of the Pittsburgh Sleep Quality Index (PSQI), a self-report assessment of past-month sleep quality. To better understand potential mechanisms, mediation models relating sleep disturbance to CUD outcomes were evaluated.

METHODS

This is a secondary analysis of data from cocaine-dependent (n = 290) participants in a multi-site trial evaluating smoking-cessation treatment for stimulant-dependent patients. The PSQI was collected at baseline; the outcomes of interest were cocaine and drug abstinence at end-of-treatment (weeks 9-10). Potential mediators, measured in weeks 1-8, were: cocaine craving (Brief Substance Craving Scale); and anxiety and depression symptoms (Hospital Anxiety and Depression Scale). Mediation techniques were used to evaluate mediation effects separately and jointly.

RESULTS

The majority of participants (58.3%) had baseline sleep disturbance. Sleep disturbance was not a significant predictor of end-of-treatment abstinence when regressed without consideration of mediators. Cocaine craving, anxiety, and depression were significant mediators, both separately and jointly, of an effect of baseline sleep disturbance on end-of-treatment abstinence.

CONCLUSION

This exploratory analysis suggests that there may be an indirect relationship between self-reported sleep quality and substance use outcomes in cocaine-dependent patients, mediated by craving, anxiety, and depression.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01077024.

Dose response of acute cocaine on sleep/waking behavior in mice

Chronic cocaine use has been associated with sleep disturbances, both during active use periods and during withdrawal and abstinence. Acute cocaine also increases waking at the expense of slow wave sleep and Rapid Eye Movement in non-human subjects. However, the effects of acute cocaine on sleep/waking activity in mice, a rodent model commonly used in both sleep and addiction research due to its high genetic tractability, has yet to be investigated. Sleep/waking activity was measured via polysomnography following IP administration of three doses of cocaine (3.6, 9.6, 18 mg/kg) and vehicle control in male C57BL/6 mice. Cocaine dose-dependently increased sleep latency, increased waking time and increased fast EEG activity within waking. Increases in waking occurred primarily during the first hour following injection, followed by rebound SWS sleep. Sleep/waking activity normalized within a 24-hour period. As with humans and other rodents, cocaine dose dependently reduces sleep in a wildtype strain of mice commonly used in reward and addiction research.

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Cocaine dose dependently increases waking in mice

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Sleep following acute cocaine normalizes within a 24 h period

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Cocaine increases fast EEG activity within waking

Sleep Perception and Misperception in Chronic Cocaine Users During Abstinence

Study Objectives

During abstinence, chronic cocaine users experience an objective worsening of sleep that is perceived as qualitatively improving. This phenomenon has been termed "occult insomnia." The objective of this study was to determine whether chronic cocaine users experience positive sleep state misperception during abstinence.

Methods

Forty-three cocaine-dependent persons were admitted to an inpatient research facility for 12 days and 11 nights to participate in a treatment study of modafinil. Polysomnographic sleep recordings were performed on study nights 3, 4, 10, and 11, when participants were on average 1 and 2 weeks abstinent from cocaine. Participants also completed sleep diary questionnaires every evening before bed and every morning upon awakening. Polysomnographic and sleep diary measurements of total sleep time, sleep latency, time awake after sleep onset, and time in bed after final awakening were compared.

Results

Chronic cocaine users accurately reported total sleep time after 1 week of abstinence but overreported total sleep time by an average of 40 min after 2 weeks of abstinence. Underestimating sleep latency and time spent awake after sleep onset were responsible for this difference.

Conclusions

Positive sleep state misperception is revealed in chronic cocaine users after 2 weeks of abstinence and is consistent with the previously identified "occult insomnia" in this population.

Modafinil Treatment of Cocaine Dependence: A Systematic Review and Meta-Analysis

BACKGROUND

Currently, there is none FDA-approved medication to treat cocaine dependency. Studies conducted with various medications, including antipsychotics, antidepressants, anticonvulsants, and others, revealed inconsistent results.

OBJECTIVES

To meta-analytically investigate the efficacy and safety of modafinil in the treatment of cocaine-dependent patients.

METHODS

Randomized controlled trials with ≥20 subjects comparing the numerical therapeutic outcomes of modafinil with placebo were identified in databases, such as PUBMED, psycINFO, EMBASE, and Clinicaltrials.gov. Relevant data on efficacy and safety were extracted. Relative risk (RR) and standardized mean difference were applied for reporting dichotomous and continuous outcomes respectively. Random effects, subgroup, and meta-regression analyses were conducted to further explore the results and evaluate for any moderators.

RESULTS

In total, 11 studies (participants = 896, duration = 6.7 ± 1.9 weeks) comparing modafinil with placebo were systematically analyzed, which indicated that modafinil was not superior to placebo in improving the treatment retention rate (studies = 11, participants = 891, RR = 1.030, 95% CI = 0.918-1.156, p = .613). Similarly, data from 7/11 studies did not evidence superiority of modafinil in achieving cocaine abstinence (participants = 696, RR = 1.259, 95% CI = 0.813-1.949, p = .302). However, subgroup analysis of six studies conducted in the United States demonstrated superiority of modafinil in cocaine abstinence rate (studies = 6, participants = 669, 95% CI = 1.027-2.020, p = 0.035). In addition, no evidence suggested modafinil-related discontinuation or specific adverse events than placebo.

CONCLUSIONS

Overall, there is no evidence to conclude superiority of modafinil in increasing cocaine abstinence and treatment retention rate. However, promising result in subgroup analysis of cocaine abstinence, secondary outcomes, and good safety profile urged the need of larger studies to derive more conclusive results.

Life-time history of insomnia and hypersomnia symptoms as correlates of alcohol, cocaine and heroin use and relapse among adults seeking substance use treatment in the United States from 1991 to 1994

AIMS

To examine the association between a life-time history of insomnia and hypersomnia compared with no sleep disturbance and substance use patterns and amounts before and after a substance use treatment episode.

DESIGN

Secondary analysis of data from the Drug Abuse Treatment Outcome Studies conducted from 1991 to 1994.

SETTING

Data were collected at 96 substance use treatment programs in 11 United States cities, including short-term in-patient, long-term residential, methadone maintenance and out-patient drug-free treatment modalities.

PARTICIPANTS

Study samples included 7168 adults at treatment entry and 2965 at 12 months post-treatment entry whose primary substance use at entry was alcohol (14.7%), cocaine (62.7%) or heroin (22.6%).

MEASUREMENTS

Life-time history of insomnia and hypersomnia was assessed via self-report. Type and frequency of substance use were assessed at treatment entry. Substance use was also assessed 12 months following treatment completion. Associations were examined using linear and logistic regression with age, sex, race, education level, depression history, treatment modality and in-treatment substance use as covariates.

FINDINGS

Life-time history of insomnia, hypersomnia, both or neither was reported by 26.3, 9.5, 28.0 and 36.2% of participants, respectively. Compared with no sleep disturbance, life-time insomnia and hypersomnia were associated at treatment entry with unique substance use patterns and a higher frequency of any substance use (P < 0.001). All types of sleep disturbance were associated with higher rates of cocaine use at 12-month post-entry (odds ratios: 1.30-1.57).

CONCLUSIONS

There is evidence of an adverse association between substance use and sleep disturbance including higher frequency of all substance use before substance abuse treatment and higher rates of cocaine use after a treatment episode.

Psychostimulant drugs for cocaine dependence

BACKGROUND

Cocaine dependence is a severe disorder for which no medication has been approved. Like opioids for heroin dependence, replacement therapy with psychostimulants could be an effective therapy for treatment.

OBJECTIVES

To assess the effects of psychostimulants for cocaine abuse and dependence. Specific outcomes include sustained cocaine abstinence and retention in treatment. We also studied the influence of type of drug and comorbid disorders on psychostimulant efficacy.

SEARCH METHODS

This is an update of the review previously published in 2010. For this updated review, we searched the Cochrane Drugs and Alcohol Group Trials Register, CENTRAL, MEDLINE, Embase and PsycINFO up to 15 February 2016. We handsearched references of obtained articles and consulted experts in the field.

SELECTION CRITERIA

We included randomised parallel group controlled clinical trials comparing the efficacy of a psychostimulant drug versus placebo.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 26 studies involving 2366 participants. The included studies assessed nine drugs: bupropion, dexamphetamine, lisdexamfetamine, methylphenidate, modafinil, mazindol, methamphetamine, mixed amphetamine salts and selegiline. We did not consider any study to be at low risk of bias for all domains included in the Cochrane 'Risk of bias' tool. Attrition bias was the most frequently suspected potential source of bias of the included studies. We found very low quality evidence that psychostimulants improved sustained cocaine abstinence (risk ratio (RR) 1.36, 95% confidence interval (CI) 1.05 to 1.77, P = 0.02), but they did not reduce cocaine use (standardised mean difference (SMD) 0.16, 95% CI -0.02 to 0.33) among participants who continued to use it. Furthermore, we found moderate quality evidence that psychostimulants did not improve retention in treatment (RR 1.00, 95% CI 0.93 to 1.06). The proportion of adverse event-induced dropouts and cardiovascular adverse event-induced dropouts was similar for psychostimulants and placebo (RD 0.00, 95% CI -0.01 to 0.01; RD 0.00, 95% CI -0.02 to 0.01, respectively). When we included the type of drug as a moderating variable, the proportion of patients achieving sustained cocaine abstinence was higher with bupropion and dexamphetamine than with placebo. Psychostimulants also appeared to increase the proportion of patients achieving sustained cocaine and heroin abstinence amongst methadone-maintained, dual heroin-cocaine addicts. Retention to treatment was low, though, so our results may be compromised by attrition bias. We found no evidence of publication bias.

AUTHORS' CONCLUSIONS

This review found mixed results. Psychostimulants improved cocaine abstinence compared to placebo in some analyses but did not improve treatment retention. Since treatment dropout was high, we cannot rule out the possibility that these results were influenced by attrition bias. Existing evidence does not clearly demonstrate the efficacy of any pharmacological treatment for cocaine dependence, but substitution treatment with psychostimulants appears promising and deserves further investigation.