Pharmacological cognitive enhancement: treatment of neuropsychiatric disorders and lifestyle use by healthy people

Solriamfetol improves chronic sleep fragmentation-induced increases in sleep propensity and ameliorates explicit memory in male mice

Obstructive sleep apnea (OSA) is a highly prevalent condition characterized by episodes of partial or complete breath cessation during sleep that induces sleep fragmentation (SF). One of the frequent manifestations of OSA is the presence of excessive daytime sleepiness (EDS) associated with cognitive deficits. Solriamfetol (SOL) and modafinil (MOD) are wake-promoting agents commonly prescribed to improve wakefulness in OSA patients with EDS. This study aimed to assess the effects of SOL and MOD in a murine model of OSA characterized by periodic SF. Male C57Bl/6J mice were exposed to either control sleep (SC) or SF (mimicking OSA) during the light period (06:00 h to 18:00 h) for 4 weeks, which consistently induces sustained excessive sleepiness during the dark phase. Both groups were then randomly assigned to receive once-daily intraperitoneal injections of SOL (200 mg/kg), MOD (200 mg/kg), or vehicle for 1 week while continuing exposures to SF or SC. Sleep/wake activity and sleep propensity were assessed during the dark phase. Novel Object Recognition test, Elevated-Plus Maze Test, and Forced Swim Test were performed before and after treatment. SOL or MOD decreased sleep propensity in SF, but only SOL induced improvements in explicit memory, while MOD exhibited increased anxiety behaviors. Chronic SF, a major hallmark of OSA, induces EDS in young adult mice that is mitigated by both SOL and MOD. SOL, but not MOD, significantly improves SF-induced cognitive deficits. Increased anxiety behaviors are apparent in MOD-treated mice. Further studies aiming to elucidate the beneficial cognitive effects of SOL are warranted.

Co-treatment with low doses of buspirone prevents rewarding effects of methylphenidate and upregulates expression of 5-HT1A receptor mRNA in the nucleus accumbens

Accumulating studies consistently show that methylphenidate (MPD), the first line drug for treating Attention-Deficit Hyperactivity Disorder (ADHD), is abused by patients to whom the drug is prescribed. Like other psychostimulants, only low doses of MPD improve cognitive performance while higher doses impair it. Preventing the use of high doses of MPD is important for retaining its therapeutic efficacy. Previously, it has been shown that performance in Morris water maze test is improved in rats treated, orally, with MPD in doses of 2.5 mg/kg; but higher doses (5 mg/kg) impair it. The present study is designed to monitor rewarding effects of 2.5 mg/kg MPD in conditioned place preference (CPP) paradigm and its potential inhibition in buspirone co-treated animals. Our results show that rewarding effects of MPD in CPP paradigm are prevented in rats co-treated with buspirone in doses of 0.1 and 0.3 mg/kg. Animals treated with MPD exhibit a downregulation of 5-HT1A receptor mRNA in the nucleus accumbens which is also prevented in rats co-treated with 0.1 and 0.3 mg/kg but not 1.0 and 2.0 mg/kg buspirone. Administration of buspirone in these doses is not rewarding in CPP test and upregulates 5-HT1A receptor mRNA in the nucleus accumbens. The findings suggest that co-use of low doses of buspirone can prevent rewarding effects of MPD to help retain its therapeutic efficacy.

Understanding the relationship between safety beliefs and knowledge for cognitive enhancers in UK university students

BACKGROUND

Cognitive enhancers (CE) are prescription drugs taken, either without a prescription or at a dose exceeding that which is prescribed, to improve cognitive functions such as concentration, vigilance or memory. Previous research suggests that users believe the drugs to be safer than non-users and that they have sufficient knowledge to judge safety. However, to date no research has compared the information sources used and safety knowledge of users and non-users.

OBJECTIVES

This study compared users and non-users of CE in terms of i) their sources of knowledge about the safety of CE and ii) the accuracy of their knowledge of possible adverse effects of a typical cognitive enhancer (modafinil); and iii) how the accuracy of knowledge relates to their safety beliefs.

METHODS

Students (N = 148) from King's College London (UK) completed an anonymous online survey assessing safety beliefs, sources of knowledge and knowledge of the safety of modafinil; and indicated whether they used CE, and, if so, which drug(s).

RESULTS

The belief that the drugs are safe was greater in users than non-users. However, both groups used comparable information sources and have similar, relatively poor drug safety knowledge. Furthermore, despite users more strongly believing in the safety of CE there was no relationship between their beliefs and knowledge, in contrast to non-users who did show correlations between beliefs and knowledge.

CONCLUSION

These data suggest that the differences in safety beliefs about CE between users and non-users do not stem from use of different information sources or more accurate safety knowledge.

Modafinil-coated nanoparticle increases expressions of brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor and neuronal nuclear protein, and protects against middle cerebral artery occlusion-induced neuron apoptosis in the rat hippocampus

The present study investigates the neuroprotective effects of modafinil-coated nanoparticle in rats' hippocampal CA1 region. Male Wistar rats (n = 48) were randomly divided into four groups. Then middle cerebral artery occlusion (MCAO) was performed by inserting a silicone coat filament in the right internal carotid artery via the external carotid artery until it reached the anterior cerebral artery. Modafinil (100 mg/kg) or modafinil-coated nanoparticle (100 mg/kg) was given to the rats as an oral gavage once a day. Infarct volume, brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), neuronal nuclear protein (NeuN) and Caspase-3 and, Caspase-8 as apoptotic genes were measured in the hippocampal CA1 region. Cresyl violet staining revealed that modafinil nanoparticle significantly decreased the neurodegeneration. Reverse transcription polymerase chain reaction results showed that modafinil nanoparticle use significantly increased the expression of neurotrophic factors (even more than modafinil alone group; p = .01). Moreover, the apoptotic markers were significantly decreased in nanoparticle modafinil (MN group); p < .05). The western blot analysis and Immunohistochemistry results confirmed the neuroprotective and anti-apoptotic effects of modafinil nanoparticle. This study's results showed that the use of modafinil-coated nanoparticle has neuroprotective effects by increasing neurotrophic factors and reducing apoptosis after MCAO in the CA1 area of the hippocampus. However, further studies are needed especially, in human samples.

[Circulation of information on drugs and other substances to increase cognitive performance: a study of a Brazilian blog (2015-2017)]

By observing the processes of (bio)medicalization and pharmacologization of society, this article addresses drugs that have been used by healthy individuals to increase cognitive dimensions such as alertness, memory, and concentration. The use of so-called "smart drugs" or "nootropics" has spread among young people, aided by the internet. The circulation of information about such drugs are analyzed using a Brazilian blog called "Cérebro Turbinado," through publications available for public access between 2015 and 2017. The study adopts theoretical and methodological frameworks of the social sciences, including an anthropological perspective. Documental research was conducted on the internet, specifically with scientific dissemination materials and the material available from the aforementioned blog. The results show that the blog acts as a medium for spreading biomedical knowledge among the lay public and indicates the production of new forms of subjectivity by revealing the meanings attributed to these substances in socialization processes.

Modafinil enhances cognitive, but not emotional conflict processing via enhanced inferior frontal gyrus activation and its communication with the dorsomedial prefrontal cortex

Cognitive control regulates cognitive and emotional systems to facilitate goal-directed behavior in the context of task-irrelevant distractors. Cognitive control deficits contribute to residual functional impairments across psychiatric disorders and represent a promising novel treatment target. Translational evidence suggests that modafinil may enhance performance in executive functions; however, differential effects on regulatory control in cognitive and emotional domains have not been examined. The present pre-registered randomized-controlled pharmacological fMRI trial examined differential effects of modafinil (single-dose, 200 mg) on cognitive and emotional conflict processing. To further separate objective cognitive enhancing effects from subjective performance perception, a metacognitive paradigm was employed. Results indicated that modafinil specifically enhanced cognitive conflict performance and concomitantly increased activation in the inferior frontal gyrus and its functional communication with the dorsomedial prefrontal cortex. Exploratory analysis further revealed modafinil-enhanced basolateral amygdala reactivity to cognitive conflict, with stronger reactivity being associated with higher cognitive conflict performance. Whereas modafinil enhanced cognitive performance in the metacognitive paradigm, confidence indices remained unaffected. Overall, the present results suggest that modafinil has the potential to enhance cognitive conflict processing while leaving emotional conflict processing unaffected. On the neural level modafinil enhanced the recruitment of a network engaged in general conflict and regulatory control processes, whereas effects on the amygdala may reflect improved arousal-mediated attention processes for conflicting information. The pattern of cognitive enhancing effects in the absence of effects on affective processing suggests a promising potential to enhance cognitive control in clinical populations.

The Efficacy of Modafinil as a Cognitive Enhancer: A Systematic Review and Meta-Analysis

BACKGROUND

Animal models and human studies have identified the potential of modafinil as a cognitive enhancing agent, independent of its effects on promoting wakefulness in sleep-deprived samples. Given that single-dose applications of other putative memory enhancers (eg, D-cycloserine, yohimbine, and methylene blue) have shown success in enhancing clinical outcomes for anxiety-related disorders, we conducted a meta-analytic review examining the potential for single-dose effects for modafinil on cognitive functioning in non-sleep-deprived adults.

METHODS

A total of 19 placebo-controlled trials that examined the effects of single-dose modafinil versus placebo on the cognitive domains of attention, executive functioning, memory, or processing speed were identified, allowing for the calculation of 67 cognitive domain-specific effect sizes.

RESULTS

The overall positive effect of modafinil over placebo across all cognitive domains was small and significant (g = 0.10; 95% confidence interval, 0.05-0.15; P < 0.001). No significant differences between cognitive domains were found. Likewise, no significant moderation was found for modafinil dose (100 mg vs 200 mg) or for the populations studied (psychiatric vs nonpsychiatric).

CONCLUSIONS

In conclusion, the available evidence indicates only limited potential for modafinil to act as a cognitive enhancer outside sleep-deprived populations.

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.

Aprimoramento cognitivo e a produção de modos de subjetividade: um estudo sobre o uso de substâncias “nootrópicas” a partir de um blog brasileiro

Resumo O consumo de medicamentos para aprimorar processos mentais, como memória, concentração e estado de alerta, tem se expandido. As chamadas smart drugs e fármacos nootrópicos são utilizados na expectativa de obter melhor desempenho em tarefas profissionais e acadêmicas. Este artigo analisa a difusão do uso de medicamentos para aprimoramento cognitivo, a partir de um blog brasileiro chamado Cérebro Turbinado, com ênfase na discussão da categoria “nootrópicos”. A metodologia adotada foi a pesquisa socioantropológica documental, baseada em materiais de divulgação científica que integram o conteúdo do blog, criado em 2015 por um estudante de medicina de uma universidade pública. O blog apresenta os nootrópicos como opções mais acessíveis, seguras e igualmente eficazes em comparação com os medicamentos psicotrópicos utilizados como smart drugs. Editor e leitores produzem um saber coletivo para otimizar o desempenho cerebral. As experiências pessoais evidenciam a maneira como os indivíduos interpretam seus estados corporais e os relacionam com os medicamentos. Na esteira dos processos de farmacologização da sociedade, a produção de modos de subjetividade baseadas em uma concepção individualista dos processos de saúde/doença/incapacidade, apoiada na compreensão neuromolecular do cérebro, fundamenta-se no compartilhamento de práticas e conhecimentos sobre tais substâncias.

Modafinil protects hippocampal neurons by suppressing excessive autophagy and apoptosis in mice with sleep deprivation

BACKGROUND AND PURPOSE

Sleep deprivation compromises learning and memory in both humans and animals, and can be reversed by administration of modafinil, a drug promoting wakefulness. Dysfunctional autophagy increases activation of apoptotic cascades, ultimately leading to increased neuronal death, which can be alleviated by autophagy inhibitors. This study aimed to investigate the alleviative effect and mechanism of modafinil on the excessive autophagy occurring in the hippocampus of mice with deficiency of learning and memory induced by sleep deprivation.

EXPERIMENTAL APPROACH

The Morris water maze was used to assess the effects of modafinil on male C57BL/6Slac mice after 48-hr sleep deprivation. The HT-22 hippocampal neuronal cell line was also used. Nissl staining, transmission electron microscope, immunofluorescence, Western blot, transient transfection, and autophagy inducer were used to study the effect and mechanism of modafinil on hippocampal neurons with excessive autophagy and apoptosis.

KEY RESULTS

Modafinil improved learning and memory in sleep-deprived mice, associated with the inhibition of excessive autophage and apoptosis and an enhanced activation of the PI3K/Akt/mTOR/P70S6K signalling pathway in hippocampal neurons. These effects of modafinil were abolished by rapamycin. In addition, modafinil suppressed the aberrant autophagy and apoptosis induced by rapamycin and reactivated PI3K/Akt/mTOR/P70S6K signals in HT-22 cells.

CONCLUSIONS AND IMPLICATIONS

These results suggested that modafinil alleviated impaired learning and memory of sleep-deprived mice potentially by suppressing excessive autophagy and apoptosis of hippocampal neurons. This novel mechanism may add to our knowledge of modafinil in the clinical treatment of impaired memory caused by sleep loss.

Preclinical Models of Alzheimer's Disease: Relevance and Translational Validity

The only drugs currently approved for the treatment of Alzheimer's Disease (AD) are four acetylcholinesterase inhibitors and the NMDA antagonist memantine. Apart from these drugs, which have minimal to no clinical benefit, the 40-year search for effective therapeutics to treat AD has resulted in a clinical failure rate of 100% not only for compounds that prevent brain amyloid deposition or remove existing amyloid plaques but also those acting by a variety of other putative disease-associated mechanisms. This indicates that the preclinical data generated from current AD targets to support the selection, optimization, and translation of new chemical entities (NCEs) and biologics to clinical trials is seriously compromised. While many of these failures reflect flawed hypotheses or a lack of adequate characterization of the preclinical pharmacodynamic and pharmacokinetic (PD/PK) properties of lead NCEs-including their bioavailability and toxicity-the conceptualization, validation, and interrogation of the current animal models of AD represent key limitations. The overwhelming majority of these AD models are transgenic, based on aspects of the amyloid hypothesis and the genetics of the familial form of the disease. As a result, these generally lack construct and predictive validity for the sporadic form of the human disease. The 170 or so transgenic models, perhaps the largest number ever focused on a single disease, use rodents, mainly mice, and in addition to amyloid also address aspects of tau causality with more complex multigene models including other presumed causative factors together with amyloid. This overview discusses the current animal models of AD in the context of both the controversies surrounding the causative role of amyloid in the disease and the need to develop validated models of cognitive function/dysfunction that more appropriately reflect the phenotype(s) of human aged-related dementias. © 2019 by John Wiley & Sons, Inc.

Modelling predictors of UK undergraduates' attitudes towards smart drugs

BACKGROUND

Smart drug use is increasing but we have little insight into their use. We hypothesized that use is predicted by attitudes and various factors including incremental morality and entity intelligence beliefs would be associated with positive attitudes, whilst perception of unfairness would be associated with negative attitudes.

METHODS

UK undergraduates completed an online survey to establish attitudes towards smart drugs, previous use and likely future use as well as measures of several factors hypothesized to predict attitudes.

RESULTS

Attitudes were found to predict previous and likely future use. Attitudes were more positive in those who believed that smart drugs were harmless and those who felt they knew enough to use them safely. By contrast, perceived unfairness was associated with negative attitudes.

CONCLUSIONS

Interventions to reduce smart drug use should focus on attitudinal beliefs around potential harm and safety, as well as emphasizing the debate around unfairness.

Comparative safety and effectiveness of cholinesterase inhibitors and memantine for Alzheimer's disease: a network meta-analysis of 41 randomized controlled trials

Background

Cholinesterase inhibitors and memantine have been approved for management of Alzheimer’s disease (AD), but there has been no consensus about the choice of various types and doses of drugs at different stages. Hence, we compared and ranked the efficacy and tolerability of these available drugs.

Methods

We searched PubMed, the Cochrane Central Register of Controlled Trials, and Embase for randomized controlled trials (RCTs) published from database inception to July 21, 2017. The primary outcomes were the mean overall changes in cognitive function and responders who had any adverse events. We conducted a random-effects network meta-analysis.

Results

Forty-one RCTs were included in this study. Compared with placebo, galantamine 32 mg daily (standardized mean difference – 0.51, 95% credible interval – 0.67 to − 0.35), galantamine 24 mg daily (− 0.50, − 0.61 to − 0.40), and donepezil 10 mg daily (− 0.40, − 0.51 to − 0.29) were probably the most effective agents on cognition for mild to moderate AD, and memantine 20 mg combined with donepezil 10 mg (0.76, 0.39 to 1.11) was recommended for moderate to severe patients. Memantine showed the best profile of acceptability. Rivastigmine transdermal 15-cm² patch was the best optional treatment both in function and global changes. None of the medicines was likely to improve neuropsychiatric symptoms through this analysis.

Conclusions

Pharmacological interventions have beneficial effects on cognition, function, and global changes, but not on neuropsychiatric symptoms, through current network meta-analysis. The choice of drugs may mainly depend on the disease severity and clinical symptoms.

Electronic supplementary material

The online version of this article (10.1186/s13195-018-0457-9) contains supplementary material, which is available to authorized users.

Pharmacological and Non-pharmacological Therapies of Cognitive Impairment in Multiple Sclerosis

Background

Cognitive impairment is one of the most important clinical features of neurodegenerative disorders including multiple sclerosis (MS). Conducted research shows that up to 65 percent of MS patients have cognitive deficits such as episodic memory, sustained attention, reduced verbal fluency; however, the cognitive MS domain is information processing speed. It is the first syndrome of cognitive dysfunction and the most widely affected in MS. Occasionally these impairments occur even before the appearance of physical symptoms.

Methods

Therefore, this review focused on the current status of our knowledge about possible methods of treatment cognitive impairment in MS patients including novel strategies. Research and online content was performed using Medline and EMBASE databases.

Results

The most recent research suggests that cognitive impairment is correlated with brain lesion volume and brain atrophy. The examination of the cognitive impairment is usually based on particular neuropsychological batteries. However, it can be not enough to make a precise diagnosis. This creates a demand to find markers that might be useful for identifying patients with risk of cognitive impairment at an early stage of the disease. Currently the most promising methods consist of neuroimaging indicators, such as diffusion tensor imaging, the magnetization transfer ratio, and N-acetyl aspartate levels. Diagnosis problems are strictly connected with treatment procedures. There are two main cognitive therapies: pharmacological (disease modifying drugs (DMD), symptomatic treatments) and non-pharmacological interventions that are focused on psychological and physical rehabilitation. Some trials have shown a positive association between physical activity and the cognitive function.

Conclusion

This article is an overview of the current state of knowledge related to cognition impairment treatment in MS. Additionally, novel strategies for cognitive impairments such as cryostimulation and other complementary methods are presented.

Memory: Looking back and looking forward

This review brings together past and present achievements in memory research, ranging from molecular to psychological discoveries. Despite some false starts, major advances include our growing understanding of learning-related neural plasticity and the characterisation of different classes of memory. One striking example is the ability to reactivate targeted neuronal ensembles so that an animal will seemingly re-experience a particular memory, with the further potential to modify such memories. Meanwhile, human functional imaging studies can distinguish individual episodic memories based on voxel activation patterns. While the hippocampus continues to provide a rich source of information, future progress requires broadening our research to involve other sites. Related challenges include the need to understand better the role of glial-neuron interactions and to look beyond the synapse as the sole site of experience-dependent plasticity. Unmet goals include translating our neuroscientific knowledge in order to optimise learning and memory, especially among disadvantaged populations.

Acute Effects of Methylphenidate, Modafinil, and MDMA on Negative Emotion Processing

BACKGROUND

Stimulants such as methylphenidate and modafinil are frequently used as cognitive enhancers in healthy people, whereas 3,4-methylenedioxymethamphetamine (ecstasy) is proposed to enhance mood and empathy in healthy subjects. However, comparative data on the effects of methylphenidate and modafinil on negative emotions in healthy subjects have been partially missing. The aim of this study was to compare the acute effects of methylphenidate and modafinil on the neural correlates of fearful face processing using 3,4-methylenedioxymethamphetamine as a positive control.

METHODS

Using a double-blind, within-subject, placebo-controlled, cross-over design, 60 mg methylphenidate, 600 mg modafinil, and 125 mg 3,4-methylenedioxymethamphetamine were administrated to 22 healthy subjects while performing an event-related fMRI task to assess brain activation in response to fearful faces. Negative mood states were assessed with the State-Trait Anxiety Inventory and subjective ratings.

RESULTS

Relative to placebo, modafinil, but not methylphenidate or 3,4-methylenedioxymethamphetamine, increased brain activation within a limbic-cortical-striatal-pallidal-thalamic circuit during fearful face processing. Modafinil but not methylphenidate also increased amygdala responses to fearful faces compared with 3,4-methylenedioxymethamphetamine. Furthermore, activation in the middle and inferior frontal gyrus in response to fearful faces correlated positively with subjective feelings of fearfulness and depressiveness after modafinil administration.

CONCLUSIONS

Despite the cognitive enhancement effects of 600 mg modafinil in healthy people, potential adverse effects on emotion processing should be considered.

Modafinil improves attentional performance in healthy, non-sleep deprived humans at doses not inducing hyperarousal across species

The wake-promoting drug modafinil is frequently used off-label to improve cognition in psychiatric and academic populations alike. The domain-specific attentional benefits of modafinil have yet to be quantified objectively in healthy human volunteers using tasks validated for comparison across species. Further, given that modafinil is a low-affinity inhibitor for the dopamine and norepinephrine transporters (DAT/NET respectively) it is unclear if any effects are attributable to a non-specific increase in arousal, a feature of many catecholamine reuptake inhibitors (e.g., cocaine, amphetamine). These experiments were designed to test for domain-specific enhancement of attention and cognitive control by modafinil (200 and 400 mg) in healthy volunteers using the 5-choice continuous performance task (5C-CPT) and Wisconsin Card Sort Task (WCST). An additional cross-species assessment of arousal and hyperactivity was performed in this group and in mice (3.2, 10, or 32 mg/kg) using species-specific versions of the behavioral pattern monitor (BPM). Modafinil significantly enhanced attention (d prime) in humans performing the 5C-CPT at doses that did not affect WCST performance or induce hyperactivity in the BPM. In mice, only the highest dose elicited increased activity in the BPM. These results indicate that modafinil produces domain-specific enhancement of attention in humans not driven by hyperarousal, unlike other drugs in this class, and higher equivalent doses were required for hyperarousal in mice. Further, these data support the utility of using the 5C-CPT across species to more precisely determine the mechanism(s) underlying the pro-cognitive effects of modafinil and potentially other pharmacological treatments.

Comparative Effects of Methylphenidate, Modafinil, and MDMA on Response Inhibition Neural Networks in Healthy Subjects

BACKGROUND

Psychostimulants such as methylphenidate and modafinil are increasingly used by healthy people for cognitive enhancement purposes, whereas the acute effect of 3,4-methylenedioxymethamphetamine (ecstasy) on cognitive functioning in healthy subjects remains unclear. This study directly compared the acute effects of methylphenidate, modafinil, and 3,4-methylenedioxymethamphetamine on the neural mechanisms underlying response inhibition in healthy subjects.

METHODS

Using a double-blind, within-subject, placebo-controlled, cross-over design, methylphenidate, modafinil, and 3,4-methylenedioxymethamphetamine were administrated to 21 healthy subjects while performing a go/no-go event-related functional magnetic resonance imaging task to assess brain activation during motor response inhibition.

RESULTS

Relative to placebo, methylphenidate and modafinil but not 3,4-methylenedioxymethamphetamine improved inhibitory performance. Methylphenidate significantly increased activation in the right middle frontal gyrus, middle/superior temporal gyrus, inferior parietal lobule, presupplementary motor area, and anterior cingulate cortex compared with placebo. Methylphenidate also induced significantly higher activation in the anterior cingulate cortex and presupplementary motor area and relative to modafinil. Relative to placebo, modafinil significantly increased activation in the right middle frontal gyrus and superior/inferior parietal lobule, while 3,4-methylenedioxymethamphetamine significantly increased activation in the right middle/inferior frontal gyrus and superior parietal lobule.

CONCLUSIONS

Direct comparison of methylphenidate, modafinil, and 3,4-methylenedioxymethamphetamine revealed broad recruitment of fronto-parietal regions but specific effects of methylphenidate on middle/superior temporal gyrus, anterior cingulate cortex, and presupplementary motor area activation, suggesting dissociable modulations of response inhibition networks and potentially the superiority of methylphenidate in the enhancement of cognitive performance in healthy subjects.

Lifestyle use of drugs by healthy people for enhancing cognition, creativity, motivation and pleasure

Today, there is continued, and in some cases growing, availability of not only psychoactive substances, including treatments for mental health disorders such as cognitive enhancers, which can enhance or restore brain function, but also 'recreational' drugs such as novel psychoactive substances (NPS). The use of psychoactive drugs has both benefits and risks: whilst new drugs to treat cognitive symptoms in neuropsychiatric or neurodegenerative disorders could have great benefits for many patient groups, the increasing ease of accessibility to recreational NPS and the increasing lifestyle use of cognitive enhancers by healthy people means that the effective management of psychoactive substances will be an issue of increasing importance. Clearly, the potential benefits of cognitive enhancers are large and increasingly relevant, particularly as the population ages, and for this reason, we should continue to devote resources to the development of cognitive enhancers as treatments for neurodegenerative diseases and psychiatric disorders, including Alzheimer's disease, attention deficit hyperactivity disorder and schizophrenia. However, the increasing use of cognitive enhancers by healthy individuals raises safety, ethical and regulatory concerns, which should not be ignored. Similarly, understanding the short- and long-term consequences of the use of NPS, as well as better understanding the motivations and profiles of users could promote more effective prevention and harm reduction measures. Linked Articles This article is part of a themed section on Pharmacology of Cognition: a Panacea for Neuropsychiatric Disease? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.19/issuetoc.

Methylphenidate Enhances Early-Stage Sensory Processing and Rodent Performance of a Visual Signal Detection Task

Methylphenidate (MPH) is used clinically to treat attention-deficit/hyperactivity disorder (ADHD) and off-label as a performance-enhancing agent in healthy individuals. MPH enhances catecholamine transmission via blockade of norepinephrine (NE) and dopamine (DA) reuptake transporters. However, it is not clear how this action affects neural circuits performing cognitive and sensorimotor functions driving performance enhancement. The dorsal lateral geniculate nucleus (dLGN) is the primary thalamic relay for visual information from the retina to the cortex and is densely innervated by NE-containing fibers from the locus coeruleus (LC), a pathway known to modulate state-dependent sensory processing. Here, MPH was evaluated for its potential to alter stimulus-driven sensory responses and behavioral outcomes during performance of a visual signal detection task. MPH enhanced activity within individual neurons, ensembles of neurons, and visually-evoked potentials (VEPs) in response to task light cues, while increasing coherence within theta and beta oscillatory frequency bands. MPH also improved reaction times to make correct responses, indicating more efficient behavioral performance. Improvements in reaction speed were highly correlated with faster VEP latencies. Finally, immunostaining revealed that catecholamine innervation of the dLGN is solely noradrenergic. This work suggests that MPH, acting via noradrenergic mechanisms, can substantially affect early-stage sensory signal processing and subsequent behavioral outcomes.

Methylphenidate, modafinil, and caffeine for cognitive enhancement in chess: A double-blind, randomised controlled trial

Stimulants and caffeine have been proposed for cognitive enhancement by healthy subjects. This study investigated whether performance in chess - a competitive mind game requiring highly complex cognitive skills - can be enhanced by methylphenidate, modafinil or caffeine. In a phase IV, randomized, double-blind, placebo-controlled trial, 39 male chess players received 2×200mg modafinil, 2×20mg methylphenidate, and 2×200mg caffeine or placebo in a 4×4 crossover design. They played twenty 15-minute games during two sessions against a chess program (Fritz 12; adapted to players' strength) and completed several neuropsychological tests. Marked substance effects were observed since all three substances significantly increased average reflection time per game compared to placebo resulting in a significantly increased number of games lost on time with all three treatments. Treatment effects on chess performance were not seen if all games (n=3059) were analysed. Only when controlling for game duration as well as when excluding those games lost on time, both modafinil and methylphenidate enhanced chess performance as demonstrated by significantly higher scores in the remaining 2876 games compared to placebo. In conjunction with results from neuropsychological testing we conclude that modifying effects of stimulants on complex cognitive tasks may in particular result from more reflective decision making processes. When not under time pressure, such effects may result in enhanced performance. Yet, under time constraints more reflective decision making may not improve or even have detrimental effects on complex task performance.

Methylphenidate has nonlinear dose effects on cued response inhibition in adults but not adolescents

Ongoing development of the dopamine system during adolescence may provide a partial mechanism for behavioral and psychiatric vulnerabilities. Despite early evidence for a hyperactive adolescent dopaminergic system, recent data suggest that adolescent dopamine may be functionally hypoactive compared to in adults. While this distinction has been established in response to dopaminergic drugs and natural rewards, little is known about age-related differences in cognitive efficacy of dopaminergic drugs. Using a recently established Cued Response Inhibition Task, we tested the effects of acute systemic methylphenidate, commonly known as Ritalin, on response inhibition and response initiation in adolescent and adults rats. First, we replicated previous data that adolescents are able to inhibit a response to a cue on par with adults, but are slower to produce a rewarded response after a stop cue. Next, we observed that methylphenidate modulated response inhibition in adult rats, with low dose (0.3mg/kg) improving inhibition, and high dose (3mg/kg) impairing performance. This dose-response pattern is commonly observed with psychostimulant cognitive modulation. In adolescents, however, methylphenidate had no effect on response inhibition at any dose. Latency of response initiation after the stop cue was not affected by methylphenidate in either adult or adolescent rats. These data establish that dose-response of a commonly prescribed psychostimulant medication is different in adolescents and adults. They further demonstrate that healthy adolescent response inhibition is not as sensitive to psychostimulants as in adults, supporting the idea that the dopamine system is hypoactive in adolescence. This article is part of a Special Issue entitled SI: Adolescent plasticity.

Pharmacological Neuroenhancement in the Field of Economics-Poll Results from an Online Survey

Introduction: The use of over-the-counter, prescription, and illicit drugs to increase attention, concentration, or memory—often called (pharmacological) neuroenhancement—shows a broad range of prevalence rates among students. However, very little data is available on neuroenhancement among employed persons. The aim of this study was to provide first data on substance use for neuroenhancement among readers of the German “Handelsblatt” coming from the field of economics.

Methods: Readers of the online edition of the Handelsblatt, a leading print and online medium for the field of economics, were invited to participate in a survey via a link on the journal homepage to complete a web-based questionnaire. Within the questionnaire, participants were asked for their gender, current age, current professional status, hours of work per week, prevalence rates of substance use for the purpose of neuroenhancement as well as for reasons of its use. Binary regression analyses with stepwise forward selection were used to predict the dependent variables “use of illicit and prescription drugs for neuroenhancement” (yes/no), “use of over-the-counter drugs for neuroenhancement” (yes/no), and “use of any drug for neuroenhancement” (yes/no).

Results: A total of 1021 participants completed the anonymous survey. Lifetime prevalence for the use of any drug for neuroenhancement was 88.0% and for the use of illicit and prescription drugs for neuroenhancement 19.0%. Reasons and situations that predicted neuroenhancement with illicit and prescription drugs were “curiosity,” “to enhance mood,” ”for a confident appearance,” “stress/pressure to perform,” and “deadline pressure.”

Discussion: The study shows that neuroenhancement with drugs is a widespread and frequent phenomenon among people belonging to the professional field of economics. Given in the literature that the use of drugs, especially prescription, and illicit drugs, may be associated with side effects, the high epidemic of drug use for neuroenhancement also shown in the present paper underlines the new public health concern of neuroenhancement.

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.