Modafinil: a review of neurochemical actions and effects on cognition

Impulsivity and attentional bias as predictors of modafinil treatment outcome for retention and drug use in crack-cocaine dependent patients: Results of a randomised controlled trial

BACKGROUND

High impulsivity and attentional bias are common in cocaine-dependent patients and predict poor treatment outcomes. The pharmacological agent modafinil is studied for its cognitive-enhancing capacities and may therefore improve clinical outcomes in crack-cocaine dependent patients. In this study, we investigated first whether pre-treatment impulsivity and attentional bias predict treatment outcome; next whether the drug modafinil given as an add-on treatment to cognitive behavioural therapy (CBT) improves impulsivity and attentional bias; and last, whether changes in impulsivity and attentional bias are related to improvements in treatment outcome.

METHODS

Crack-cocaine dependent outpatients (n = 65) were randomised to 12 weeks CBT plus modafinil (400 mg/day) or only CBT. Self-reported impulsivity was assessed at baseline using the Barratt Impulsiveness Scale. At baseline and Week 12, we assessed inhibitory control as a behavioural measure of impulsivity, in terms of cognitive interference (Stroop task) and response inhibition ('stop-signal task'), and attentional bias with the addiction Stroop task. Clinical outcomes were CBT-retention and crack-cocaine use.

RESULTS

At baseline, self-reported impulsivity predicted better CBT-retention; low self-reported and behavioural impulsivity and attentional bias predicted less crack-cocaine use. Changes in cognitive performance were not modafinil-related, but most likely due to low adherence. Improvements in impulsivity or attentional bias were not associated with CBT-retention nor changes in crack-cocaine use.

CONCLUSIONS

Baseline impulsivity and attentional bias predicted clinical outcomes in crack-cocaine dependent patients. There were no firm indications that modafinil reduced impulsivity nor attentional bias in this population. Future studies involving cognitive-enhancing medications should include strategies to optimise adherence, to be better able to evaluate their potential.

Impact of Astroglial Connexins on Modafinil Pharmacological Properties

STUDY OBJECTIVES

Modafinil is a non-amphetaminic wake-promoting compound used as therapy against sleepiness and narcolepsy. Its mode of action is complex, but modafinil has been recently proposed to act as a cellular-coupling enhancer in glial cells, through modulation of gap junctions constituted by connexins. The present study investigated in mice the impact of connexins on the effects of modafinil using connexin inhibitors.

METHODS

Modafinil was administered alone or combined with inhibitors of astrocyte connexin, meclofenamic acid, or flecainide, respectively, acting on Cx30 and Cx43. Sleep-wake states were monitored in wild-type and narcoleptic orexin knockout mice. A spontaneous alternation task was used to evaluate working memory in wild-type mice. The effects of the compounds on astroglial intercellular coupling were determined using dye transfer in acute cortical slices.

RESULTS

Meclofenamic acid had little modulation on the effects of modafinil, but flecainide enhanced the wake-promoting and pro-cognitive effects of modafinil. Co-administration of modafinil/flecainide resulted in a marked decrease in the number and duration of direct transitions to rapid eye movement sleep, which are characteristic of narcoleptic episodes in orexin knockout mice. Furthermore, modafinil enhanced the connexin-mediated astroglial cell coupling, whereas flecainide reduced it. Finally, this modafinil-induced effect was reversed by co-administration with flecainide.

CONCLUSIONS

Our study indicates that flecainide impacts the pharmacological effects of modafinil, likely through the normalization of Cx30-dependent gap junctional coupling in astroglial networks. The enhancement of the wake-promoting, behavioral, and cognitive outcomes of modafinil demonstrated here with flecainide would open new perspectives in the management of sleep disorders such as narcolepsy.

COMMENTARY

A commentary on this article appears in this issue on page 1175.

Drugs, games, and devices for enhancing cognition: implications for work and society

As work environments change, the demands on working people change. Cognitive abilities in particular are becoming progressively more important for work performance and successful competition in a global environment. However, work-related stress, performance over long hours, lack of sleep, shift work, and jet lag affect cognitive functions. Therefore, an increasing number of healthy people are reported to use cognitive-enhancing drugs, as well as other interventions, such as noninvasive brain stimulation, to maintain or improve work performance. This review summarizes research on pharmacological and technical methods as well as cognitive training, including game apps for the brain, in healthy people. In neuropsychiatric disorders, impairments in cognitive functions can drastically reduce the chances of returning to work; therefore, this review also summarizes findings from pharmacological and cognitive-training studies in neuropsychiatric disorders.

Sustained Modafinil Treatment Effects on Control-Related Gamma Oscillatory Power in Schizophrenia

Control-related cognitive processes such as rule selection and maintenance are associated with cortical oscillations in the gamma range, and modulated by catecholamine neurotransmission. Control-related gamma power is impaired in schizophrenia, and an understudied treatment target. It remains unknown whether pro-catecholamine pharmacological agents augment control-related gamma oscillations in schizophrenia. We tested the effects of 4-week fixed-dose daily adjunctive modafinil (MOD) 200 mg, in a randomized double-blind, placebo-controlled, parallel-groups design. Twenty-seven stable schizophrenia patients performed a cognitive control task during EEG, at baseline and after 4 weeks of treatment. EEG data underwent time-frequency decomposition with Morlet wavelets to determine power of 4-80 Hz oscillations. The modafinil group (n=14), relative to placebo group (n=13), exhibited enhanced oscillatory power associated with high-control rule selection in the gamma range after treatment, with additional effects during rule maintenance in gamma and sub-gamma ranges. MOD-treated patients who exhibited improved task performance with treatment also showed greater treatment-related delay period gamma compared with MOD-treated patients without improved performance. This is the first evidence in schizophrenia of augmentation of cognition-related gamma oscillations by an FDA-approved agent with therapeutic potential. Gamma oscillations represent a novel treatment target in this disorder, and modulation of catecholamine signaling may represent a viable strategy at this target.

Augmented Reality as a Countermeasure for Sleep Deprivation

Sleep deprivation is known to have serious deleterious effects on executive functioning and job performance. Augmented reality has an ability to place pertinent information at the fore, guiding visual focus and reducing instructional complexity. This paper presents a study to explore how spatial augmented reality instructions impact procedural task performance on sleep deprived users. The user study was conducted to examine performance on a procedural task at six time points over the course of a night of total sleep deprivation. Tasks were provided either by spatial augmented reality-based projections or on an adjacent monitor. The results indicate that participant errors significantly increased with the monitor condition when sleep deprived. The augmented reality condition exhibited a positive influence with participant errors and completion time having no significant increase when sleep deprived. The results of our study show that spatial augmented reality is an effective sleep deprivation countermeasure under laboratory conditions.

Correlating behaviour and gene expression endpoints in the dopaminergic system after modafinil administration in mouse

The mechanisms of action of modafinil continue to be poorly characterised and its potential for abuse in preclinical models remains controverted. The aim of this study was to further elucidate the mechanism of action of modafinil, through a potential behavioural and molecular association in the mouse. A conditioned place preference (CPP) paradigm was implemented to investigate the rewarding properties of modafinil. Whole genome expression and qRT-PCR analysis were performed on the ventral tegmental area (VTA), nucleus accumbens (NAC) and prefrontal cortex (PFC) of modafinil-treated and control animals. Modafinil administration (65 mg/kg) induced an increase in locomotor activity, an increase in the change of preference for the drug paired side after a conditioning period as well as changes to gene expression profiles in the VTA (120 genes), NAC (23 genes) and PFC (19 genes). A molecular signature consisting of twelve up-regulated genes was identified as common to the three brain regions. Multiple linear correlation analysis showed a strong correlation (R(2)>0.70) between the behavioural and molecular endpoints in the three brain regions. We show that modafinil had a concomitant effect on CPP, locomotor activity, and up-regulation of interferon-γ (IFN-γ) regulated genes (Gbp2, Gbp3, Gbp10, Cd274, Igtp), while correlating the latter set of genes with behaviour changes evaluated through the CPP. A potential association can be proposed based on the dysregulation of p47 family genes and Gbp family of IFN-γ induced GTPases. In conclusion, these findings suggest a link between the behavioural and molecular events in the context of modafinil administration.

Identification of Treatment Targets in a Genetic Mouse Model of Voluntary Methamphetamine Drinking

Methamphetamine has powerful stimulant and euphoric effects that are experienced as rewarding and encourage use. Methamphetamine addiction is associated with debilitating illnesses, destroyed relationships, child neglect, violence, and crime; but after many years of research, broadly effective medications have not been identified. Individual differences that may impact not only risk for developing a methamphetamine use disorder but also affect treatment response have not been fully considered. Human studies have identified candidate genes that may be relevant, but lack of control over drug history, the common use or coabuse of multiple addictive drugs, and restrictions on the types of data that can be collected in humans are barriers to progress. To overcome some of these issues, a genetic animal model comprised of lines of mice selectively bred for high and low voluntary methamphetamine intake was developed to identify risk and protective alleles for methamphetamine consumption, and identify therapeutic targets. The mu opioid receptor gene was supported as a target for genes within a top-ranked transcription factor network associated with level of methamphetamine intake. In addition, mice that consume high levels of methamphetamine were found to possess a nonfunctional form of the trace amine-associated receptor 1 (TAAR1). The Taar1 gene is within a mouse chromosome 10 quantitative trait locus for methamphetamine consumption, and TAAR1 function determines sensitivity to aversive effects of methamphetamine that may curb intake. The genes, gene interaction partners, and protein products identified in this genetic mouse model represent treatment target candidates for methamphetamine addiction.

A Novel Heterocyclic Compound CE-104 Enhances Spatial Working Memory in the Radial Arm Maze in Rats and Modulates the Dopaminergic System

Various psychostimulants targeting monoamine neurotransmitter transporters (MATs) have been shown to rescue cognition in patients with neurological disorders and improve cognitive abilities in healthy subjects at low doses. Here, we examined the effects upon cognition of a chemically synthesized novel MAT inhibiting compound 2-(benzhydrylsulfinylmethyl)-4-methylthiazole (named as CE-104). The efficacy of CE-104 in blocking MAT [dopamine transporter (DAT), serotonin transporter (SERT), and norepinephrine transporter] was determined using in vitro neurotransmitter uptake assay. The effect of the drug at low doses (1 and 10 mg/kg) on spatial memory was studied in male rats in the radial arm maze (RAM). Furthermore, the dopamine receptor and transporter complex levels of frontal cortex (FC) tissue of trained and untrained animals treated either with the drug or vehicle were quantified on blue native PAGE (BN-PAGE). The drug inhibited dopamine (IC₅₀: 27.88 μM) and norepinephrine uptake (IC₅₀: 160.40 μM), but had a negligible effect on SERT. In the RAM, both drug-dose groups improved spatial working memory during the performance phase of RAM as compared to vehicle. BN-PAGE Western blot quantification of dopamine receptor and transporter complexes revealed that D1, D2, D3, and DAT complexes were modulated due to training and by drug effects. The drug’s ability to block DAT and its influence on DAT and receptor complex levels in the FC is proposed as a possible mechanism for the observed learning and memory enhancement in the RAM.

Cognitive enhancers versus addictive psychostimulants: The good and bad side of dopamine on prefrontal cortical circuits

In this review we describe how highly addictive psychostimulants such as cocaine and methamphetamine actions might underlie hypoexcitabilty in frontal cortical areas observed in clinical and preclinical models of psychostimulant abuse. We discuss new mechanisms that describe how increments on synaptic dopamine release are linked to reduce calcium influx in both pre and postsynaptic compartments on medial PFC networks, therefore modulating synaptic integration and information. Sustained DA neuromodulation by addictive psychostimulants can "lock" frontal cortical networks in deficient states. On the other hand, other psychostimulants such as modafinil and methylphenidate are considered pharmacological neuroenhancement agents that are popular among healthy people seeking neuroenhancement. More clinical and preclinical research is needed to further clarify mechanisms of actions and physiological effects of cognitive enhancers which show an opposite pattern compared to chronic effect of addictive psychostimulants: they appear to increase cortical excitability. In conclusion, studies summarized here suggest that there is frontal cortex hypoactivity and deficient inhibitory control in drug-addicted individuals. Thus, additional research on physiological effects of cognitive enhancers like modafinil and methylphenidate seems necessary in order to expand current knowledge on mechanisms behind their therapeutic role in the treatment of addiction and other neuropsychiatric disorders.

Effect of Pharmacological Interventions on the Fronto-Cingulo-Parietal Cognitive Control Network in Psychiatric Disorders: A Transdiagnostic Systematic Review of fMRI Studies

Executive function deficits, such as working memory, decision-making, and attention problems, are a common feature of several psychiatric disorders for which no satisfactory treatment exists. Here, we transdiagnostically investigate the effects of pharmacological interventions (other than methylphenidate) on the fronto-cingulo-parietal cognitive control network, in order to identify functional brain markers for future procognitive pharmacological interventions. Twenty-nine manuscripts investigated the effect of pharmacological treatment on executive function-related brain correlates in psychotic disorders (n = 11), depression (n = 4), bipolar disorder (n = 4), ADHD (n = 4), OCD (n = 2), smoking dependence (n = 2), alcohol dependence (n = 1), and pathological gambling (n = 1). In terms of impact on the fronto-cingulo-parietal network, the preliminary evidence for catechol-O-methyl-transferase inhibitors, nicotinic receptor agonists, and atomoxetine was relatively consistent, the data for atypical antipsychotics and anticonvulsants moderate, and interpretation of the data for antidepressants was hampered by the employed study designs. Increased activity in task-relevant areas and decreased activity in task-irrelevant areas were the most common transdiagnostic effects of pharmacological treatment. These markers showed good positive and moderate negative predictive value. It is concluded that fronto-cingulo-parietal activity changes can serve as a marker for future procognitive interventions. Future recommendations include the use of randomized double-blind designs and selective cholinergic and glutamatergic compounds.

Effects of modafinil and R-modafinil on brain stimulation reward thresholds: implications for their use in the treatment of psychostimulant dependence

BACKGROUND

Modafinil and its enantiomer R-modafinil are approved for the treatment of various sleep disorders, and may also be efficacious in the treatment of psychostimulant abuse. However, the ability of modafinil and R-modafinil to alter brain reward function has not yet been assessed.

PURPOSE

This study assessed the effects of modafinil and R-modafinil on brain reward function using the intracranial self-stimulation (ICSS) paradigm.

STUDY DESIGN

Male Sprague-Dawley rats were trained to respond for ICSS using current-intensity threshold determination procedures. Changes in ICSS thresholds were then assessed following administration of modafinil and R-modafinil (50, 100, and 150 mg/kg), or cocaine (2.5 - 20 mg/kg) as a positive control.

RESULTS

ICSS thresholds were reduced by modafinil at the 150 mg/kg dose, as well as by cocaine at the 10 and 20 mg/kg doses. R-modafinil only produced non-significant trends towards reducing ICSS thresholds.

CONCLUSION

Modafinil and R-modafinil have limited effects on brain reward function in otherwise drug-naïve subjects. Additional assessments of these effects in the context of psychostimulant dependence are needed.

Effects of Modafinil on Behavioral Learning and Hippocampal Synaptic Transmission in Rats

Purpose:

Modafinil is a wake-promoting agent that has been proposed to improve cognitive performance at the preclinical and clinical levels. Since there is insufficient evidence for modafinil to be regarded as a cognitive enhancer, the aim of this study was to investigate the effects of chronic modafinil administration on behavioral learning in healthy adult rats.

Methods:

Y-maze training was used to assess learning performance, and the whole-cell patch clamp technique was used to assess synaptic transmission in pyramidal neurons of the hippocampal CA1 region of rats.

Results:

Intraperitoneal administration of modafinil at 200 mg/kg or 300 mg/kg significantly improved learning performance. Furthermore, perfusion with 1mM modafinil enhanced the frequency and amplitude of spontaneous postsynaptic currents and spontaneous excitatory postsynaptic currents in CA1 pyramidal neurons in hippocampal slices. However, the frequency and amplitude of spontaneous inhibitory postsynaptic currents in CA1 pyramidal neurons were inhibited by treatment with 1mM modafinil.

Conclusions:

These results indicate that modafinil improves learning and memory in rats possibly by enhancing glutamatergic excitatory synaptic transmission and inhibiting GABAergic (gamma-aminobutyric acid-ergic) inhibitory synaptic transmission.

Pharmacotherapy for chronic cognitive impairment in traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a major cause of chronic disability. Worldwide, it is the leading cause of disability in the under 40s, resulting in severe disability in some 150 to 200 million people per annum. In addition to mood and behavioural problems, cognition-particularly memory, attention and executive function-are commonly impaired by TBI. Cognitive problems following TBI are one of the most important factors in determining people's subjective well-being and their quality of life. Drugs are widely used in an attempt to improve cognitive functions. Whilst cholinergic agents in TBI have been reviewed, there has not yet been a systematic review or meta-analysis of the effect on chronic cognitive problems of all centrally acting pharmacological agents.

OBJECTIVES

To assess the effects of centrally acting pharmacological agents for treatment of chronic cognitive impairment subsequent to traumatic brain injury in adults.

SEARCH METHODS

We searched ALOIS-the Cochrane Dementia and Cognitive Improvement Group's Specialised Register-on 16 November 2013, 23 February 2013, 20 January 2014, and 30 December 2014 using the terms: traumatic OR TBI OR "brain injury" OR "brain injuries" OR TBIs OR "axonal injury" OR "axonal injuries". ALOIS contains records of clinical trials identified from monthly searches of a number of major healthcare databases, numerous trial registries and grey literature sources. Supplementary searches were also performed in MEDLINE, EMBASE, PsycINFO, The Cochrane Library, CINAHL, LILACs, ClinicalTrials.gov, the World Health Organization (WHO) Portal (ICTRP) and Web of Science with conference proceedings.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) assessing the effectiveness of any one centrally acting pharmacological agent that affects one or more of the main neurotransmitter systems in people with chronic traumatic brain injury; and there had to be a minimum of 12 months between the injury and entry into the trial.

DATA COLLECTION AND ANALYSIS

Two review authors examined titles and abstracts of citations obtained from the search. Relevant articles were retrieved for further assessment. A bibliographic search of relevant papers was conducted. We extracted data using a standardised tool, which included data on the incidence of adverse effects. Where necessary we requested additional unpublished data from study authors. Risk of bias was assessed by a single author.

MAIN RESULTS

Only four studies met the criteria for inclusion, with a total of 274 participants. Four pharmacological agents were investigated: modafinil (51 participants); (-)-OSU6162, a monoamine stabiliser (12 participants of which six had a TBI); atomoxetine (60 participants); and rivastigmine (157 participants). A meta-analysis could not be performed due to the small number and heterogeneity of the studies.All studies examined cognitive performance, with the majority of the psychometric sub-tests showing no difference between treatment and placebo (n = 274, very low quality evidence). For (-)-OSU6162 modest superiority over placebo was demonstrated on three measures, but markedly inferior performance on another. Rivastigmine was better than placebo on one primary measure, and a single cognitive outcome in a secondary analysis of a subgroup with more severe memory impairment at baseline. The study of modafinil assessed clinical global improvement (n = 51, low quality evidence), and did not find any difference between treatment and placebo. Safety, as measured by adverse events, was reported by all studies (n = 274, very low quality evidence), with significantly more nausea reported by participants who received rivastigmine compared to placebo. There were no other differences in safety between treatment and placebo. No studies reported any deaths.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine whether pharmacological treatment is effective in chronic cognitive impairment in TBI. Whilst there is a positive finding for rivastigmine on one primary measure, all other primary measures were not better than placebo. The positive findings for (-)-OSU6162 are interpreted cautiously as the study was small (n = 6). For modafinil and atomoxetine no positive effects were found. All four drugs appear to be relatively well tolerated, although evidence is sparse.

Dopaminergic mediation of the discriminative stimulus functions of modafinil in rats

RATIONALE

Modafinil is a wake-promoting drug with FDA approval for the treatment of excessive daytime sleepiness that has been prescribed for ADHD and recently assessed as a potential treatment for psychostimulant dependence. Previous research indicates that modafinil modestly increases locomotor activity and produces similar discriminative stimulus effects to psychostimulants in rodents, although the subjective effects of modafinil are reportedly distinct from those of cocaine or amphetamine in humans with a history of psychostimulant abuse.

OBJECTIVES

The current study employed drug discrimination procedures in rats to examine the pharmacological actions contributing to modafinil's discriminative stimulus functions.

METHODS

Eight male Sprague-Dawley rats were trained to discriminate intragastric administration of 256 mg/kg modafinil from vehicle (5% arabic gum) under a FR 20 schedule of food reinforcement. Substitution tests were conducted with various dopaminergic agents (d-amphetamine, cocaine, PNU-91356A, GBR 12909, methylphenidate) and nondopaminergic agents (nicotine, ethanol). Antagonist tests were conducted with the selective D1 antagonist, SCH 39166, and the nonselective D2 antagonist, haloperidol.

RESULTS

Rats trained to discriminate modafinil displayed complete stimulus generalization to cocaine, methylphenidate, and GBR 12909 and the discrimination was completely blocked by both SCH 39166 and haloperidol. Evidence for significant partial substitution was obtained with d-amphetamine, PNU-91356A, and nicotine.

CONCLUSIONS

Results strongly support the role of dopaminergic mechanisms in the discriminative stimulus functions of modafinil, although further evaluation regarding the contribution of other neurotransmitter systems to these effects should be continued. The findings are discussed in light of clinical research efforts with modafinil as a treatment for psychostimulant dependence.

The relationship between sleep quality and neurocognition in bipolar disorder

BACKGROUNDS

Sleep and circadian rhythm disruptions are prominent, trait-like features of bipolar disorder (BD) which precede the onset of mood episodes. Neurocognitive impairments also characterize BD not only during acute phases of the illness but also during remission. Although the relationship between these two debilitating aspects of the illness might seem intuitive, very little is known about their relationship. We examined the association between sleep dysfunction and neurocognition in BD.

METHODS

In a sample of 117 BD patients (mean age=45.0±10.7; 59.0% (n=69) male), neurocognitive functioning was assessed using the MATRICS Consensus Cognitive Battery (MCCB). Sleep quality data were collected using the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI). Partial Pearson correlations tested for a relationship between sleep and neurocognition. Path analyses were conducted to examine the hypothesized direct influence of sleep disruption on neurocognition.

RESULTS

Higher levels of sleep disruptions were associated with a more severe clinical presentation and poorer performance in social cognition, visual learning and working memory. Social cognition and working memory were directly (negatively) predicted by sleep disruptions.

LIMITATIONS

The study was limited by a relatively small sample size and the lack of behavioral and biological objectives measure of activity/rest cycles.

CONCLUSIONS

Our study suggests that in patients with BD, sleep disruptions have a detrimental effect on general level of psychopathology and contribute directly to impaired cognitive functioning in the domains of social cognition and working memory. More research using objective measurement of sleep should be pursued to support these data and to further investigate the causal relationship between these disabling aspects of the illness.

Modafinil May Alleviate Poststroke Fatigue: A Randomized, Placebo-Controlled, Double-Blinded Trial

BACKGROUND AND PURPOSE

Poststroke fatigue is common and reduces quality of life. Current evidence for intervention is limited, and this is the first placebo-controlled trial to investigate treatment of poststroke fatigue with the wakefulness promoting drug modafinil.

METHODS

The trial was randomized, double-blinded, and placebo-controlled. Patients were treated with 400-mg modafinil or placebo for 90 days. Assessments were done at inclusion, 30, 90, and 180 days. The primary end point was fatigue at 90 days measured by the Multidimensional Fatigue Inventory-20 general fatigue domain. Secondary end points included the Fatigue Severity Scale, the Montreal Cognitive Assessment, the modified Rankin Scale and the Stroke-specific quality of Life questionnaire. Adult patients with a recent stroke achieving a score of ≥12 on the Multidimensional Fatigue Inventory-20 general fatigue domain were consecutively included. Exclusion criteria were severe cognitive disabilities and contraindications for modafinil treatment.

RESULTS

One thousand one hundred twenty-one patients with stroke were screened and 41 patients included, 21 received modafinil. The primary end point, the Multidimensional Fatigue Inventory-20 general fatigue score, did not differ between groups. Patients in the modafinil group obtained better scores on the Fatigue Severity Scale (P=0.02) and in some subscales of the stroke-specific quality of life questionnaire (0.001<P<0.05), which were secondary outcomes. No serious adverse reactions were observed and there was no difference in blood pressure between groups.

CONCLUSIONS

There were no significant differences between the 2 groups with regard to the primary end point. There were secondary significant outcomes that should be explored in future trials.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01800097.

Structured cues or modafinil for fatigue amelioration in clinicians? A double-blind, randomized controlled trial of critical clinical information recall in fatigued clinicians

OBJECTIVES

To evaluate the impact of modafinil on "free" and "cued" recall of clinical information in fatigued but nonsleep-deprived clinicians.

SUMMARY BACKGROUND DATA

Despite attempts to minimize sleep deprivation through redesign of the roster of residents and staff surgeons, evidence suggests that fatigue remains prevalent. The wake-promoting agent modafinil improves cognition in the sleep-deprived fatigued state and may improve information recall in fatigued nonsleep-deprived clinicians.

METHODS

Twenty-four medical undergraduates participated in a double-blind, parallel, randomized controlled trial (modafinil-200 mg:placebo). Medication was allocated 2 hours before a 90-minute fatigue-inducing, continuous performance task (dual 2-back task). A case history memorization task was then performed. Clinical information recall was assessed as "free"(no cognitive aids) and "cued"(using aid memoirs). Open and closed cues represent information of increasing specificity to aid the recall of clinical information. Fatigue was measured objectively using the psychomotor vigilance task at induction, before and after the dual 2-back task.

RESULTS

Modafinil decreased false starts and lapses (modafinil = 0.50, placebo = 9.83, P < .05) and improved psychomotor vigilance task performance (Decreased Performance, modafinil = 0.006, placebo = 0.098, P < .05). Modafinil improved free information recall (modafinil = 137.8, placebo = 106.0, P < .01). There was no significant difference between groups in the amount of information recalled with open (modafinil = 62.3, placebo = 52.8, P = .1) and closed cues (modafinil = 80.1, placebo = 75.9, P = .3).

CONCLUSION

Modafinil attenuated fatigue and improved free recall of clinical information without improving cue-based recall under the design of our experimental conditions. Memory cues to aid retrieval of clinical information are convenient interventions that could decrease fatigue-related error without adverse effects of the neuropharmacology.

Modafinil for cognitive neuroenhancement in healthy non-sleep-deprived subjects: A systematic review

Modafinil is an FDA-approved eugeroic that directly increases cortical catecholamine levels, indirectly upregulates cerebral serotonin, glutamate, orexin, and histamine levels, and indirectly decreases cerebral gamma-amino-butrytic acid levels. In addition to its approved use treating excessive somnolence, modafinil is thought to be used widely off-prescription for cognitive enhancement. However, despite this popularity, there has been little consensus on the extent and nature of the cognitive effects of modafinil in healthy, non-sleep-deprived humans. This problem is compounded by methodological discrepancies within the literature, and reliance on psychometric tests designed to detect cognitive effects in ill rather than healthy populations. In order to provide an up-to-date systematic evaluation that addresses these concerns, we searched MEDLINE with the terms "modafinil" and "cognitive", and reviewed all resultant primary studies in English from January 1990 until December 2014 investigating the cognitive actions of modafinil in healthy non-sleep-deprived humans. We found that whilst most studies employing basic testing paradigms show that modafinil intake enhances executive function, only half show improvements in attention and learning and memory, and a few even report impairments in divergent creative thinking. In contrast, when more complex assessments are used, modafinil appears to consistently engender enhancement of attention, executive functions, and learning. Importantly, we did not observe any preponderances for side effects or mood changes. Finally, in light of the methodological discrepancies encountered within this literature, we conclude with a series of recommendations on how to optimally detect valid, robust, and consistent effects in healthy populations that should aid future assessment of neuroenhancement.

Reality of evidence-based practice in palliative care

There has been a paradigm shift in medicine away from tradition, anecdote and theoretical reasoning from the basic sciences towards evidence-based medicine (EBM). In palliative care however, statistically significant benefits may be marginal and may not be related to clinical meaningfulness. The typical treatment vs. placebo comparison necessitated by ‘gold standard’ randomised controlled trials (RCTs) is not necessarily applicable. The complex multimorbidity of end of life care involves considerations of the patient’s physical, psychological, social and spiritual needs. In addition, the field of palliative care covers a heterogeneous group of chronic and incurable diseases no longer limited to cancer. Adequate sample sizes can be difficult to achieve, reducing the power of studies and high attrition rates can result in inadequate follow up periods. This review uses examples of the management of cancer-related fatigue and death rattle (noisy breathing) to demonstrate the current state of EBM in palliative care. The future of EBM in palliative care needs to be as diverse as the patients who ultimately derive benefit. Non-RCT methodologies of equivalent quality, validity and size conducted by collaborative research networks using a ‘mixed methods approach’ are likely to pose the correct clinical questions and derive evidence-based yet clinically relevant outcomes.

Investigating the underlying mechanisms of aberrant behaviors in bipolar disorder from patients to models: Rodent and human studies

Psychiatric patients with bipolar disorder suffer from states of depression and mania, during which a variety of symptoms are present. Current treatments are limited and neurocognitive deficits in particular often remain untreated. Targeted therapies based on the biological mechanisms of bipolar disorder could fill this gap and benefit patients and their families. Developing targeted therapies would benefit from appropriate animal models which are challenging to establish, but remain a vital tool. In this review, we summarize approaches to create a valid model relevant to bipolar disorder. We focus on studies that use translational tests of multivariate exploratory behavior, sensorimotor gating, decision-making under risk, and attentional functioning to discover profiles that are consistent between patients and rodent models. Using this battery of translational tests, similar behavior profiles in bipolar mania patients and mice with reduced dopamine transporter activity have been identified. Future investigations should combine other animal models that are biologically relevant to the neuropsychiatric disorder with translational behavioral assessment as outlined here. This methodology can be utilized to develop novel targeted therapies that relieve symptoms for more patients without common side effects caused by current treatments.

Differential effects of wake promoting drug modafinil in aversive learning paradigms

Modafinil (MO) an inhibitor of the dopamine transporter was initially approved to treat narcolepsy, a sleep related disorder in humans. One interesting “side-effect” of this drug, which emerged from preclinical and clinical studies, is the facilitation of cognitive performance. So far, this was primarily shown in appetitive learning paradigms, but it is yet unclear whether MO exerts a more general cognitive enhancement effect. Thus, the aim of the present study in rats was to extend these findings by testing the effects of MO in two aversive paradigms, Pavlovian fear conditioning (FC) and the operant two-way active avoidance (TWA) learning paradigms. We discovered a differential, task-dependent effect of MO. In the FC paradigm MO treated rats showed a dose-dependent enhancement of fear memory compared to vehicle treated rats, indicated by increased context-related freezing. Cue related fear memory remained unaffected. In the TWA paradigm MO induced a significant decrease of avoidance responses compared to vehicle treated animals, while the number of escape reactions during the acquisition of the TWA task remained unaffected. These findings expand the knowledge in the regulation of cognitive abilities and may contribute to the understanding of the contraindicative effects of MO in anxiety related mental disorders.

Pupil diameter reflects uncertainty in attentional selection during visual search

Pupil diameter has long been used as a metric of cognitive processing. However, recent advances suggest that the cognitive sources of change in pupil size may reflect LC-NE function and the calculation of unexpected uncertainty in decision processes (Aston-Jones and Cohen, 2005; Yu and Dayan, 2005). In the current experiments, we explored the role of uncertainty in attentional selection on task-evoked changes in pupil diameter during visual search. We found that task-evoked changes in pupil diameter were related to uncertainty during attentional selection as measured by reaction time (RT) and performance accuracy (Experiments 1-2). Control analyses demonstrated that the results are unlikely to be due to error monitoring or response uncertainty. Our results suggest that pupil diameter can be used as an implicit metric of uncertainty in ongoing attentional selection requiring effortful control processes.

Modafinil Increases Awake EEG Activation and Improves Performance in Obstructive Sleep Apnea during Continuous Positive Airway Pressure Withdrawal

OBJECTIVES

We examined the changes in waking electroencephalography (EEG) biomarkers with modafinil during continuous positive airway pressure (CPAP) withdrawal in patients with obstructive sleep apnea (OSA) to investigate neurophysiological evidence for potential neurocognitive improvements.

DESIGN

Randomized double-blind placebo-controlled crossover study. CPAP was used for the first night and then withdrawn for 2 subsequent nights. Each morning after the 2 CPAP withdrawal nights, patients received either 200 mg modafinil or placebo. After a 5-w washout, the procedure repeated with the crossover drug.

SETTINGS

University teaching hospital.

PARTICIPANTS

Stable CPAP users (n = 23 men with OSA).

MEASUREMENT AND RESULTS

Karolinska Drowsiness Test (KDT) (awake EEG measurement with eyes open and closed), Psychomotor Vigilance Task (PVT), and driving simulator Performance were assessed bihourly during the 3 testing days following CPAP treatment and CPAP withdrawal nights. Compared to placebo, modafinil significantly increased awake EEG activation (faster EEG frequency) with increased alpha/delta (A/D) ratio (P < 0.0001) and fast ratio = (alpha+beta)/(delta+theta) (P < 0.0001) across the 2 days of CPAP withdrawal. The A/D ratio significantly correlated with the driving simulator response time (P = 0.015), steering variation (P = 0.002), and PVT reaction time (P = 0.006). In contrast, individual EEG band power of alpha, beta, theta, and delta did not correlate with any neurocognitive performance.

CONCLUSIONS

Modafinil administration during continuous positive airway pressure (CPAP) withdrawal increased awake EEG activation, which correlated to improved performance. This study provides supporting neurophysiological evidence that modafinil is a potential short-term treatment option during acute CPAP withdrawal.

Modafinil combined with cognitive training: pharmacological augmentation of cognitive training in schizophrenia

Several efforts to develop pharmacological treatments with a beneficial effect on cognition in schizophrenia are underway, while cognitive remediation has shown modest effects on cognitive performance. Our goal was to test if pharmacological augmentation of cognitive training would result in enhancement of training-induced learning. We chose modafinil as the pharmacological augmenting agent, as it is known to have beneficial effects on learning and cognition. 49 participants with chronic schizophrenia were enroled in a double-blind, placebo-controlled study across two sites and were randomised to either modafinil (200mg/day) or placebo. All participants engaged in a cognitive training program for 10 consecutive weekdays. The primary outcome measure was the performance on the trained tasks and secondary outcome measures included MATRICS cognitive battery, proxy measures of everyday functioning and symptom measures. 84% of the participants completed all study visits. Both groups showed significant improvement in the performance of the trained tasks suggesting potential for further learning. Modafinil did not induce differential enhancement on the performance of the trained tasks or any differential enhancement of the neuropsychological and functional measures compared to placebo. Modafinil showed no significant effects on symptom severity. Our study demonstrated that combining pharmacological compounds with cognitive training is acceptable to patients and can be implemented in large double-blind randomised controlled trials. The lack of differential enhancement of training-induced learning raises questions, such as choice and optimal dose of drug, cognitive domains to be trained, type of cognitive training, intervention duration and chronicity of illness that require systematic investigation in future studies.

Neuroenhancement of Exposure Therapy in Anxiety Disorders

Although exposure-based treatments and anxiolytic medications are more effective than placebo for treating anxiety disorders, there is still considerable room for further improvement. Interestingly, combining these two modalities is usually not more effective than the monotherapies. Recent translational research has identified a number of novel approaches for treating anxiety disorders using agents that serve as neuroenhancers (also known as cognitive enhancers). Several of these agents have been studied to determine their efficacy at improving treatment outcome for patients with anxiety and other psychiatric disorders. In this review, we examine d-cycloserine, yohimbine, cortisol, catecholamines, oxytocin, modafinil, and nutrients such as caffeine and amino fatty acids as potential neuroenhancers. Of these agents, d-cycloserine shows the most promise as an effective neuroenhancer for extinction learning and exposure therapy. Yet, the optimal dosing and dose timing for drug administration remains uncertain. There is partial support for cortisol, catecholamines, yohimbine and oxytocin for improving extinction learning and exposure therapy. There is less evidence to indicate that modafinil and nutrients such as caffeine and amino fatty acids are effective neuroenhancers. More research is needed to determine their long term efficacy and clinical utility of these agents.

The prevalence, measurement, and treatment of the cognitive dimension/domain in major depressive disorder

Insufficient outcomes amongst adults with major depressive disorder (MDD) provide the impetus to identify and refine therapeutic targets that are most critical to outcome from patient, provider, and societal perspectives. Towards this aim, a pivotal shift towards the transnosological domain, cognition, is occurring in the study of MDD and other brain disorders. This paper aims to provide a framework for conceptualizing and prioritizing cognitive function amongst adults with MDD with a particular view to provide a conceptual framework for research and clinical priorities. We also summarize extant data pertaining to psychotropic effects, notably antidepressants, on the cognitive dimension/domain. This narrative review was based on articles identified through a PubMed/MEDLINE search of all English-language articles published between January 1966 and October 2014. The search words were major depressive disorder, depression, unipolar depression, cognition, cognitive dysfunction, cognitive deficit, and cognitive function. The search was supplemented with a manual review of relevant references. The selection of articles for inclusion in this review was based on overall methodological quality as well as on their pertinence to informing the framework described herein. Cognitive dysfunction in MDD is a discrete domain subserved by discrete yet overlapping substrates. There is a need to provide a glossary of terms commonly employed in the cognition literature for consensus as to the appropriate screening, measurement, and monitoring tools. The guiding principle of measurement-based care should include systematic assessment and measurement of cognition in subpopulations with MDD, as a tactic to improve outcome. Relatively few treatment strategies have demonstrated efficacy specifically for the cognitive domain in MDD. The antidepressant vortioxetine has replicated evidence of specific pro-cognitive effects in adults with MDD across multiple subdomains of cognitive function. Vortioxetine is a novel antidepressant that is hypothesized to act through a combination of direct effects on receptor activity and serotonin receptor inhibition, as well as other systems. Pro-cognitive effects for other US FDA-approved agents are suggested, but pseudospecificity has not been excluded as a possible explanation of their beneficial effects on cognitive function. A disparate assortment of other agents are currently under investigation for possible benefit in mitigating cognitive deficits and improving cognitive performance (e.g., intranasal insulin, erythropoietin, anti-inflammatory agents). Non-pharmacological approaches including, but not limited to, cognitive remediation (CR), aerobic exercise, and neuromodulation are promising.

Cognitive enhancing agents in schizophrenia and bipolar disorder

Cognitive dysfunction is a core feature of schizophrenia and is also present in bipolar disorder (BD). Whereas decreased intelligence precedes the onset of psychosis in schizophrenia and remains relatively stable thereafter; high intelligence is a risk factor for bipolar illness but cognitive function decreases after onset of symptoms. While in schizophrenia, many studies have been conducted on the development of cognitive enhancing agents; in BD such studies are almost non-existent. This review focuses on the pharmacological agents with putative effects on cognition in both schizophrenia and bipolar illness; specifically agents targeting the dopaminergic, cholinergic and glutamatergic neurotransmitter pathways in schizophrenia and the cognitive effects of lithium, anticonvulsants and antipsychotics in BD. In the final analysis we conclude that cognitive enhancing agents have not yet been produced convincingly for schizophrenia and have hardly been studied in BD. Importantly, studies should focus on other phases of the illness. To be able to treat cognitive deficits effectively in schizophrenia, patients in the very early stages of the illness, or even before - in the ultra-high risk stages - should be targeted. In contrast, cognitive deficits occur later in BD, and therefore drugs should be tested in BD after the onset of illness. Hopefully, we will then find effective drugs for the incapacitating effects of cognitive deficits in these patients.

Cognitive training programs for childhood cancer patients and survivors: A critical review and future directions

A robust literature has developed documenting neurocognitive late effects in survivors of leukemia and central nervous system (CNS) tumors, the most frequent cancer diagnoses of childhood. Patterns of late effects include deficits in attention and concentration, working memory, processing speed, and executive function, as well as other domains. As childhood cancer survivors are living longer, ameliorating deficits both in broad and specific neurocognitive domains has been increasingly recognized as an endeavor of paramount importance. Interventions to improve cognitive functioning were first applied to the field of pediatric oncology in the 1990s, based on strategies used effectively with adults who had sustained a traumatic brain injury (TBI). Compilation and modification of these techniques has led to the development of structured cognitive training programs, with the effectiveness and feasibility of such interventions currently an active area of research. Consequently, the purpose of this critical review is to: (1) review cognitive training programs intended to remediate or prevent neurocognitive deficits in pediatric cancer patients and survivors, (2) critically analyze training program strengths and weaknesses to inform practice, and (3) provide recommendations for future directions of clinical care and research.

Fixed drug eruptions with modafinil

Modafinil is a psychostimulant drug, which has been approved by the US Food and Drug Administration for the treatment of narcolepsy associated excessive daytime sleepiness, sleep disorder related to shift work, and obstructive sleep apnea syndrome. However, presently it is being used as a lifestyle medicine; in India, it has been misused as an "over the counter" drug. Modafinil is known to have several cutaneous side effects. Fixed drug eruption (FDE) is a distinctive drug induced reaction pattern characterized by recurrence of eruption at the same site of the skin or mucous membrane with repeated systemic administration. Only two case reports exist in the literature describing modafinil induced FDE until date. Here, we report two similar cases. The increasing use of this class of drug amongst the medical personnel might be posing a threat to the proper use and encouraging subsequent abuse. There might be a considerable population using these drugs unaware of the possible adverse effects. Authorities should be more alert regarding the sale and distribution of such medicines.

Monoamine reuptake inhibitors in Parkinson's disease

The motor manifestations of Parkinson's disease (PD) are secondary to a dopamine deficiency in the striatum. However, the degenerative process in PD is not limited to the dopaminergic system and also affects serotonergic and noradrenergic neurons. Because they can increase monoamine levels throughout the brain, monoamine reuptake inhibitors (MAUIs) represent potential therapeutic agents in PD. However, they are seldom used in clinical practice other than as antidepressants and wake-promoting agents. This review article summarises all of the available literature on use of 50 MAUIs in PD. The compounds are divided according to their relative potency for each of the monoamine transporters. Despite wide discrepancy in the methodology of the studies reviewed, the following conclusions can be drawn: (1) selective serotonin transporter (SERT), selective noradrenaline transporter (NET), and dual SERT/NET inhibitors are effective against PD depression; (2) selective dopamine transporter (DAT) and dual DAT/NET inhibitors exert an anti-Parkinsonian effect when administered as monotherapy but do not enhance the anti-Parkinsonian actions of L-3,4-dihydroxyphenylalanine (L-DOPA); (3) dual DAT/SERT inhibitors might enhance the anti-Parkinsonian actions of L-DOPA without worsening dyskinesia; (4) triple DAT/NET/SERT inhibitors might exert an anti-Parkinsonian action as monotherapy and might enhance the anti-Parkinsonian effects of L-DOPA, though at the expense of worsening dyskinesia.

Cognition as a target in major depression: new developments

Major depressive disorder (MDD) is a highly prevalent and disabling psychiatric illness often accompanied of cognitive dysfunction which may persist even when patients achieve clinical remission. Currently, cognitive deficits emerge as a potential target because they compromise the functional outcome of depressed patients. The aim of this study was to review data for several potential pharmacological treatments targeting cognition in MDD, resulting from monotherapy or adjunctive treatment. An extensive and systematic Pubmed/Medline search of the published literature until March 2014 was conducted using a variety of search term to find relevant articles. Bibliographies of retrieved papers were further examined for publications of interest. Searches were limited to articles available in English language. We describe studies using modafinil, lisdexamfetamine, ketamine, lanicemine, memantine, galantamine, donepezil, vortioxetine, intranasal oxytocin, omega-3, s-adenosyl-methionine, scopolamine and erythropoietin. From these articles, we determined that there are a number of promising new therapies, pharmacological agents or complementary medicines, but data are just emerging. Drugs and therapies targeting cognitive dysfunction in MDD should prove effective in improving specific cognitive domains and functioning, while ruling out pseudospecificity.

Behavioral, biological, and chemical perspectives on atypical agents targeting the dopamine transporter

BACKGROUND

Treatment of stimulant-use disorders remains a formidable challenge, and the dopamine transporter (DAT) remains a potential target for antagonist or agonist-like substitution therapies.

METHODS

This review focuses on DAT ligands, such as benztropine, GBR 12909, modafinil, and DAT substrates derived from phenethylamine or cathinone that have atypical DAT-inhibitor effects, either in vitro or in vivo. The compounds are described from a molecular mechanistic, behavioral, and medicinal-chemical perspective.

RESULTS

Possible mechanisms for atypicality at the molecular level can be deduced from the conformational cycle for substrate translocation. For each conformation, a crystal structure of a bacterial homolog is available, with a possible role of cholesterol, which is also present in the crystal of Drosophila DAT. Although there is a direct relationship between behavioral potencies of most DAT inhibitors and their DAT affinities, a number of compounds bind to the DAT and inhibit dopamine uptake but do not share cocaine-like effects. Such atypical behavior, depending on the compound, may be related to slow DAT association, combined sigma-receptor actions, or bias for cytosol-facing DAT. Some structures are sterically small enough to serve as DAT substrates but large enough to also inhibit transport. Such compounds may display partial DA releasing effects, and may be combined with release or uptake inhibition at other monoamine transporters.

CONCLUSIONS

Mechanisms of atypical DAT inhibitors may serve as targets for the development of treatments for stimulant abuse. These mechanisms are novel and their further exploration may produce compounds with unique therapeutic potential as treatments for stimulant abuse.

Modafinil and its metabolites enhance the anticonvulsant action of classical antiepileptic drugs in the mouse maximal electroshock-induced seizure model

RATIONALE

Seizures occur when the excitability of brain circuits is not sufficiently restrained by inhibitory mechanisms. Although modafinil is reported to reduce GABA-activated currents and extracellular GABA levels in the brain, the drug exerts anticonvulsant effects in animal studies.

OBJECTIVES

The aim of this study was to determine the effects of modafinil and its metabolites (sulfone and carboxylic acid) on the anticonvulsant action of four classical antiepileptic drugs (AEDs)-carbamazepine (CBZ), phenobarbital (PB), phenytoin (PHT), and valproate (VPA).

METHODS

Anticonvulsant activity was assessed with the maximal electroshock seizure threshold (MEST) test and MES test in mice. Brain concentrations of AEDs were measured to ascertain any pharmacokinetic contribution to the observed anticonvulsant effects.

RESULTS

Intraperitoneal injection of 75 mg kg(-1) of modafinil or its metabolites significantly elevated the threshold for electroconvulsions in mice, whereas 50 mg kg(-1) of each compound enhanced the anticonvulsant activity of CBZ, PHT, and VPA, but not that of PB. A 25-mg kg(-1) dose of modafinil or its sulfone metabolite enhanced anticonvulsant activity of VPA. Modafinil and its metabolites (50 mg kg(-1)) did not alter total brain concentrations of PB and VPA but did elevate CBZ and PHT.

CONCLUSIONS

Enhancement of anticonvulsant actions of VPA by modafinil in the mouse MES model is a pharmacodynamic effect. Collectively, our data suggest that modafinil may be a safe and beneficial adjunct to the therapeutic effects of AEDs in human patients.

Distinct pro-vigilant profile induced in rats by the mGluR5 potentiator LSN2814617

While treatment options are available, excessive daytime sleepiness (EDS) remains a significant unmet medical need for many patients. Relatively little rodent behavioural pharmacology has been conducted in this context to assess potential pro-vigilant compounds for their ability to restore functional capacity following experimentally induced sleep loss. Male Wistar rats were prepared for electroencephalographic (EEG) recording and subject to 11 h of sleep restriction using a biofeedback-induced cage rotation protocol. A simple response latency task (SRLT) was used to behaviourally index sleep restriction and the effects of pro-vigilant compounds: modafinil, D-amphetamine, caffeine, and the mGlu5-positive allosteric modulator LSN2814617. Sleep restriction resulted in a consistent, quantified loss of non-rapid eye movement (NREM) and REM sleep that impaired SRLT performance in a manner suggestive of progressive task disengagement. In terms of EEG parameters, all compounds induced wakefulness. Amphetamine treatment further decreased SRLT performance capacity, whereas the other three compounds decreased omissions and allowed animals to re-engage in the task. Caffeine and modafinil also significantly increased premature responses during this period, an effect not observed for LSN2814617. While all compounds caused compensatory sleep responses, the magnitude of compensation observed for LSN2814617 was much smaller than would be predicted to result from the prolongation of wakefulness exhibited. Using simple response latencies to index performance, an mGlu5 PAM dramatically increased wakefulness and improved functional capacity of sleep-restricted animals, without eliciting a proportionate compensatory sleep response. This effect was qualitatively distinct from that of amphetamine, caffeine and modafinil.

Antipsychotic augmentation with modafinil or armodafinil for negative symptoms of schizophrenia: systematic review and meta-analysis of randomized controlled trials

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) of modafinil or armodafinil (ar/mod) augmentation in schizophrenia. We searched PubMed, clinical trial registries, reference lists, and other sources for parallel group, placebo-controlled RCTs. Our primary outcome variable was the effect of ar/mod on negative symptom outcomes. Eight RCTs (pooled N = 372; median duration, 8 weeks) met our selection criteria. Ar/mod (200 mg/day) significantly attenuated negative symptom ratings (6 RCTs; N = 322; standardized mean difference [SMD], -0.26; 95% CI, -0.48 to -0.04). This finding remained similar in all but one sensitivity analysis - when the only RCT in acutely ill patients was excluded, the outcome was no longer statistically significant (SMD, -0.17; 95% CI, -0.51 to 0.06). The absolute advantage for ar/mod was small: just 0.27 points on the PANSS-N (6 RCTs). Ar/mod attenuated total psychopathology ratings (7 RCTs; N = 342; SMD, -0.23; 95% CI, -0.45 to -0.02) but did not influence positive symptom ratings (5 RCTs; N = 302; mean difference, -0.58; 95% CI, -1.71 to 0.55). Although data were limited, cognition, fatigue, daytime drowsiness, adverse events, and drop out rates did not differ significantly between ar/mod and placebo groups. Fixed and random effects models yielded similar results. There was no heterogeneity in all but one analysis. Publication bias could not be tested. We conclude that ar/mod (200 mg/day) is safe and well tolerated in the short-term treatment of schizophrenia. Ar/mod reduces negative symptoms with a small effect size; the absolute advantage is also small, and the advantage disappears when chronically ill patients or those with high negative symptom burden are treated. Ar/mod does not benefit or worsen other symptom dimensions in schizophrenia.

The integrative management of treatment-resistant depression: a comprehensive review and perspectives

BACKGROUND

Major depressive disorder is a prevalent and disabling illness. Notwithstanding numerous advances in the pharmacological treatment of depression, approximately 70% of patients do not remit after first-line antidepressant treatment.

METHODS

The MEDLINE/PubMed, EMBASE and ClinicalTrials.gov electronic databases were searched from inception to October 1, 2013, for randomized controlled trials (RCT), relevant open-label trials, meta-analyses and ongoing trials of pharmacological and psychotherapeutic approaches to treatment-resistant depression (TRD).

RESULTS

Switching to a different antidepressant is a useful option following nonresponse to a first-line agent. Although widely used in clinical practice, there is limited evidence to support antidepressant combination for TRD. Notwithstanding evidence for lithium or T3 augmentation to be successful in TRD, most studies were carried out when participants were treated with tricyclic antidepressants (TCA). Of the available strategies to augment the response to new-generation antidepressants, the use of some atypical antipsychotics is best supported by evidence. Several novel therapeutic options are currently discussed. Evidence suggests that cognitive therapy (CT) is an effective strategy for TRD.

CONCLUSIONS

The success of switching to a different antidepressant following a first-line agent is supported by evidence, but there is limited evidence for effective combination strategies. Lithium and T3 augmentation of TCA have the strongest evidence base for successful treatment of TRD. The use of augmentation of newer-generation antidepressants with atypical antipsychotics is supported by a growing evidence base. Current evidence supports CT as an effective strategy for TRD. There is a need for additional large-scale RCT of TRD. The development of new antidepressants targeting novel pathways opens a promising perspective for the management of TRD.

[Neuroenhancement]

BACKGROUND

Cognitive enhancement or neuroenhancement describes the increase in cognitive performance in humans by means of psychotropic drugs or brain stimulation methods, such as transcranial magnetic stimulation (TMS).

PROBLEM

This article discusses the potential of pharmacological cognitive enhancement with some of the most common drugs.

METHODS

A selective literature search was performed taking into account the most important groups of substances (i.e. caffeine, nicotine, stimulants including modafinil, and acetylcholine esterase inhibitors) for which studies on the pharmacological elevation of cognitive performance in healthy subjects are available.

RESULTS

The extent of the effects that can be pharmacologically achieved is essentially genetically determined. Some of the best-characterized polymorphisms are described here. Pharmacological enhancement of cognitive performance is currently possible with all of the compounds described here and caffeine and nicotine are used by millions of people without the explicit intention of most consumers of cognitive enhancement.

DISCUSSION

Clinical neuroscientists are required to share their expertise to a greater extent in the social discourse on cognitive enhancement in the future in order to influence opinion-forming and decision-making processes.

Pharmacological approaches to manage persistent symptoms of major depressive disorder: rationale and therapeutic strategies

Major depressive disorder (MDD) is a highly prevalent chronic psychiatric illness associated with significant morbidity, mortality, loss of productivity, and diminished quality of life. Typically, only a minority of patients responds to treatment and meet criteria for remission as residual symptoms may persist, the result of an inadequate course of treatment and/or the presence of persistent side effects. The foremost goal of treatment should be to restore patients to full functioning and eliminate or relieve all MDD symptoms, while being virtually free of troublesome side effects. The current available pharmacological options to manage persistent depressive symptoms include augmentation or adjunctive combination strategies, both of which target selected psychobiological systems and specific mood and somatic symptoms experienced by the patient. As well, non-pharmacological interventions including psychotherapies may be used in either first-line or adjunctive approaches. However, the evidence to date with respect to available adjunct therapies is limited by few studies and those published have utilized only a small number of subjects and lack enough data to allow for a consensus of expert opinion. This underlines the need for further longer term, large population-based studies and those that include comorbid populations, all of which are seen in real world community psychiatry.

Modafinil effects on middle-frequency oscillatory power during rule selection in schizophrenia

Control-related cognitive processes such as rule selection are associated with cortical oscillations in the theta, alpha and, beta ranges, and modulated by catecholamine neurotransmission. Thus, a potential strategy for improving cognitive control deficits in schizophrenia would be to use pro-catecholamine pharmacological agents to augment these control-related oscillations. In a double-blind, placebo-controlled (within-subjects) study, we tested the effects of adjunctive single-dose modafinil 200 mg on rule-related 4-30 Hz oscillations in 23 stable schizophrenia patients, using EEG during cognitive control task performance. EEG data underwent time-frequency decomposition with Morlet wavelets to determine the power of 4-30 Hz oscillations. Modafinil (relative to placebo) enhanced oscillatory power associated with high-control rule selection in theta, alpha, and beta ranges, with modest effects during rule maintenance. Modafinil treatment in schizophrenia augments middle-frequency cortical oscillatory power associated with rule selection, and may subserve diverse subcomponent processes in proactive cognitive control.

Frontostriatal circuits and the development of bulimia nervosa

Bulimia nervosa (BN) is characterized by both recurrent episodes of binge eating that are, in part, defined by a sense of loss of control and compensatory behaviors to avoid weight gain. Impulsive behaviors are also common in individuals with BN, indicating more pervasive difficulties in behavioral self-regulation. Findings from functional and anatomical neuroimaging studies of individuals with BN suggest dysfunction in the dorsal frontostriatal circuits that support self-regulatory capacities and habit learning and in overlapping ventral circuits that support reward processing and reward-based learning. In this review, we describe the normal development of frontostriatal circuits and then present behavioral and neuroimaging data from adolescents and adults with BN. These data suggest that the abnormal maturation of frontostriatal circuits may contribute to the habitual binge-eating and purging behaviors of BN. Future longitudinal imaging studies will improve understanding of how these circuits contribute to the developmental trajectory of BN and will inform novel interventions that could target or prevent the impulsive and habit-like features of this disorder.

The warrior in the machine: neuroscience goes to war

Ever since Stone Age men discovered that knapping flint produced sharp stone edges that could be used in combat as well as for cooking and hunting, technological advances of all kinds have been adapted and adopted by the military.The opportunities provided by modern neuroscience are proving no exception, but their application in a military context is accompanied by complex practical and ethical considerations.

Modafinil increases the latency of response in the Hayling Sentence Completion Test in healthy volunteers: a randomised controlled trial

Background

Modafinil is a medication licensed for the treatment of narcolepsy. However, it has been reported that healthy individuals without wakefulness disorders are using modafinil off-label to enhance cognitive functioning. Although some studies have reported that modafinil improves cognitive task performance in healthy volunteers, numerous other studies have failed to detect cognitive enhancing effects of modafinil on several well-established neuropsychological tasks. Interestingly, several clinical and preclinical studies have found that improved cognitive task performance by modafinil is accompanied by slower response times. This observation raises the question as to whether this slowing of response time in healthy volunteers is a necessary and sufficient condition for cognitive enhancement with modafinil. The aim of the current experiment was to explore this question by investigating the effects of modafinil on the Hayling Sentence Completion Test (HSCT).

Methodology

Sixty-four healthy volunteers received either a single dose (200 mg) of modafinil (n = 32) or placebo (n = 32) in a randomized, double-blind, placebo-controlled, parallel group study in which the principal outcome measures were response latencies on the response initiation and response inhibition sections of the HSCT.

Principal Findings

Participants dosed with modafinil had significantly longer mean response latencies on the HSCT for both the response initiation and response inhibition compared to participants dosed with placebo. However, participants in both groups made a similar number of errors on each of these measures, indicating that modafinil did not enhance the accuracy of performance of the task relative to placebo.

Conclusions

This study demonstrated that administration of single 200 mg doses of modafinil to healthy individuals increased the latency of responses in the performance of the HSCT, a task that is highly sensitive to prefrontal executive function, without enhancing accuracy of performance. This finding may provide important clues to defining the limitations of modafinil as a putative cognitive enhancer.

Trial Registration

ClinicalTrials.gov NCT02051153