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Brain and Neuroscience Advances 2019The use of cognitive-enhancing drugs by healthy individuals has been a feature for much of recorded history. Cocaine and amphetamine are modern cases of drugs initially... (Review)
Review
The use of cognitive-enhancing drugs by healthy individuals has been a feature for much of recorded history. Cocaine and amphetamine are modern cases of drugs initially enthusiastically acclaimed for enhancing cognition and mood. Today, an increasing number of healthy people are reported to use cognitive-enhancing drugs, as well as other interventions, such as non-invasive brain stimulation, to maintain or improve work performance. Cognitive-enhancing drugs, such as methylphenidate and modafinil, which were developed as treatments, are increasingly being used by healthy people. Modafinil not only affects 'cold' cognition, but also improves 'hot' cognition, such as emotion recognition and task-related motivation. The lifestyle use of 'smart drugs' raises both safety concerns as well as ethical issues, including coercion and increasing disparity in society. As a society, we need to consider which forms of cognitive enhancement (e.g. pharmacological, exercise, lifelong learning) are acceptable and for which groups under what conditions and by what methods we would wish to improve and flourish.
PubMed: 32166175
DOI: 10.1177/2398212818816018 -
Arhiv Za Higijenu Rada I Toksikologiju Sep 2019An increasing number of people, students in particular, seek substances that improve their cognitive functioning. The most popular group of pharmacological cognitive... (Review)
Review
An increasing number of people, students in particular, seek substances that improve their cognitive functioning. The most popular group of pharmacological cognitive enhancers (PCEs) are stimulants. Available studies suggest a small beneficial effect of methylphenidate and amphetamine on memory, executive functions, and processing speed. However small, this effect can make the difference between success and failure. In recent years, research has focused on the additional beneficial effect on the emotional state, increased motivation, and placebo-induced cognitive enhancement. This paper briefly reviews the latest and most important research on the relationship between popular stimulants and cognitive enhancement. One cannot understand this relationship without understanding the Yerkes-Dodson law, which explains the relationship between the degree of arousal and performance. It suggests that the effect of stimulants is a dose-dependent continuum. This law has repeatedly been confirmed by studies in which an optimal level of psychoactivation for cognitive enhancement was obtained with low stimulant doses, whereas exceeding the effective dose resulted in cognitive deficits, psychomotor agitation, and addiction. A separate section has been devoted to modafinil, an increasingly popular stimulant that differs from the rest in neurochemical profile and behavioural effects.
Topics: Adult; Aged; Aged, 80 and over; Central Nervous System Stimulants; Cognition; Cognition Disorders; Female; Humans; Male; Methylphenidate; Middle Aged; Modafinil; Nootropic Agents; Psychotropic Drugs; Young Adult
PubMed: 32597132
DOI: 10.2478/aiht-2019-70-3298 -
Journal of Drug and Alcohol Research Dec 2015Modafinil and its enantiomer R-modafinil are approved for the treatment of various sleep disorders, and may also be efficacious in the treatment of psychostimulant...
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.
PubMed: 27284492
DOI: 10.4303/jdar/235958 -
The Cochrane Database of Systematic... Jan 2023Fatigue is the most commonly reported symptom in people with advanced cancer. Cancer-related fatigue (CRF) is pervasive and debilitating, and can greatly impact quality... (Review)
Review
BACKGROUND
Fatigue is the most commonly reported symptom in people with advanced cancer. Cancer-related fatigue (CRF) is pervasive and debilitating, and can greatly impact quality of life (QoL). CRF has a highly variable clinical presentation, likely due to a complex interaction of multiple factors. Corticosteroids are commonly used to improve CRF, but the benefits are unclear and there are significant adverse effects associated with long-term use. With the increasing survival of people with metastatic cancer, the long-term effects of medications are becoming increasingly relevant. Since the impact of CRF can be immensely debilitating and can negatively affect QoL, its treatment warrants further review.
OBJECTIVES
To determine the benefits and harms of corticosteroids compared with placebo or an active comparator in adults with advanced cancer and CRF.
SEARCH METHODS
We searched CENTRAL, MEDLINE, Embase, CINAHL, Science Citation Index (ISI Web of Science), LILACS, and two clinical trial registries from inception to 18 July 2022. SELECTION CRITERIA: We included randomised controlled trials in adults aged ≥18 years. We included participants with advanced cancer who were suffering from CRF. We included trials that randomised participants to corticosteroids at any dose, by any route, administered for the relief of CRF; compared to placebo or an active comparator, including supportive care or non-pharmacological treatments.
DATA COLLECTION AND ANALYSIS
Three review authors independently assessed titles identified by the search strategy; two review authors assessed risk of bias; and two extracted data. We extracted the primary outcome of participant-reported fatigue relief using validated scales and secondary outcomes of adverse events, serious adverse events and QoL. We calculated the risk ratio with 95% confidence intervals (CIs) between groups for dichotomous outcomes. We measured arithmetic mean and standard deviation, and reported the mean difference (MD) with 95% CI between groups for continuous outcomes. We used standardised mean difference (SMD) with 95% CIs when an outcome was measured with different instruments measuring the same construct. We used a random-effects model to meta-analyse the outcome data. We rated the certainty of the evidence using GRADE and created two summary of findings tables. MAIN RESULTS: We included four studies with 297 enroled participants; data were available for only 239 participants. Three studies compared corticosteroid (equivalent ≤ 8 mg dexamethasone) to placebo. One study compared corticosteroid (dexamethasone 4 mg) to an active comparator (modafinil 100 mg). There were insufficient data to evaluate subgroups, such as dose and duration of treatment. One study had a high risk of performance and detection bias due to lack of blinding, and one study had a high risk of attrition bias. Otherwise, we assessed risks of bias as low or unclear. Comparison 1: corticosteroids compared with placebo Participant-reported fatigue relief The was no clear difference between corticosteroids and placebo (SMD -0.46, 95% CI -1.07 to 0.14; 3 RCTs, 165 participants, very low-certainty evidence) for relief of fatigue at one week of the intervention. We downgraded the certainty of the evidence three times for study limitations due to unclear risk of bias, imprecision, and inconsistency. Adverse events There was no clear difference in the occurrence of adverse events between groups, but the evidence is very uncertain (3 RCTs, 165 participants; very low-certainty evidence). Serious adverse events There was no clear difference in the occurrence of serious adverse events between groups, but the evidence is very uncertain (2 RCTs, 118 participants; very low-certainty evidence). Quality of lIfe One study reported QoL at one week using the Edmonton Symptom Assessment System (ESAS) well-being, and found no clear difference in QoL between groups (MD -0.58, 95% CI -1.93 to 0.77). Another study measured QoL using the Quality of Life Questionnaire for Cancer Patients Treated with Anticancer Drugs (QoL-ACD), and found no clear difference between groups. There was no clear difference between groups for either study, but the evidence is very uncertain (2 RCTs, 118 participants; very low-certainty evidence). Comparison 2: corticosteroids compared with active comparator (modafinil) Participant-reported fatigue relief There was improvement in fatigue from baseline to two weeks in both groups (modafinil MD 10.15, 95% CI 7.43 to 12.87; dexamethasone MD 9.21, 95% CI 6.73 to 11.69), however no clear difference between the two groups (MD -0.94, 95% CI -4.49 to 2.61; 1 RCT, 73 participants, very low-certainty evidence). We downgraded the certainty of the evidence three times for very serious study limitations and imprecision. Adverse events There was no clear difference in the occurrence of adverse events between groups, but the evidence is very uncertain (1 RCT, 73 participants; very low-certainty evidence). Serious adverse events There were no serious adverse events reported in either group (1 RCT, 73 participants; very low-certainty evidence). Quality of lIfe One study measured QoL at two weeks, using the ESAS-well-being. There was marked improvement in QoL from baseline in both groups (modafinil MD -2.43, 95% CI -2.88 to -1.98; dexamethasone MD -2.16, 95% CI -2.68 to -1.64), however no clear difference between the two groups (MD 0.27, 95% CI -0.39 to 0.93; 1 RCT, 73 participants, very low-certainty evidence).
AUTHORS' CONCLUSIONS
There is insufficient evidence to support or refute the use of systemic corticosteroids in adults with cancer and CRF. We included four small studies that provided very low-certainty of evidence for the efficacy of corticosteroids in the management of CRF. Further high-quality randomised controlled trials with larger sample sizes are required to determine the effectiveness of corticosteroids in this setting.
Topics: Humans; Adult; Adolescent; Quality of Life; Modafinil; Adrenal Cortex Hormones; Neoplasms; Dexamethasone; Fatigue
PubMed: 36688471
DOI: 10.1002/14651858.CD013782.pub2 -
Psychiatria Danubina Sep 2018Modafinil is a psychostimulant drug prescribed mainly for treatment of narcolepsy but is used as a "smart drug" by wide populations to increase wakefulness,...
BACKGROUND
Modafinil is a psychostimulant drug prescribed mainly for treatment of narcolepsy but is used as a "smart drug" by wide populations to increase wakefulness, concentration and overall mental performance. The aim of this study was to assess potential developmental toxicity of modafinil.
MATERIALS AND METHODS
Pregnant female mice were given either saline or modafinil (50 mg/kg orally) from gestational day (GD) 3 to GD 10 and then a challenge dose on the GD 17. The male offspring were treated analogously at the age of 10 weeks. Changes in the spontaneous locomotor/exploratory behaviour and anxiogenic profile in the open-field test were assessed in naive animals, after an acute and 8 modafinil dose and the challenge dose following a 7-day wash-out period. One month after completion of the behavioural study, the leukocyte phagocytosis was examined by zymosan induced and luminol-aided chemiluminiscence assay in vitro.
RESULTS
The most important finding of this study was the immunosuppressing effect on leukocyte activity, hypolocomotion and increased behavioural response to modafinil-induced psychostimulation caused by prenatal exposure to the same drug. We did not detect significantly altered anxiety-related behaviour in any group disregarding the pre- and postnatal treatments.
CONCLUSION
This is the first evidence of developmental toxicity of modafinil which needs to be taken into account as a potential risk factor when modafinil is administered to women who may become or are pregnant.
Topics: Age Factors; Animals; Disease Models, Animal; Female; Gestational Age; Leukocytes; Locomotion; Luminescent Measurements; Luminol; Male; Mice; Mice, Inbred ICR; Modafinil; Phagocytosis; Pregnancy; Prenatal Exposure Delayed Effects
PubMed: 30267529
DOI: 10.24869/psyd.2018.356 -
QRB Discovery 2021Modafinil is a mild psychostimulant-like drug enhancing wakefulness, improving attention and developing performance in various cognitive tasks, but its mechanism of...
Combined electrochemistry and mass spectrometry imaging to interrogate the mechanism of action of modafinil, a cognition-enhancing drug, at the cellular and sub-cellular level.
Modafinil is a mild psychostimulant-like drug enhancing wakefulness, improving attention and developing performance in various cognitive tasks, but its mechanism of action is not completely understood. This is the first combination of amperometry, electrochemical cytometry and mass spectrometry to interrogate the mechanism of action of a drug, here modafinil, at cellular and sub-cellular level. We employed single-cell amperometry (SCA) and intracellular vesicle impact electrochemical cytometry (IVIEC) to investigate the alterations in exocytotic release and vesicular catecholamine storage following modafinil treatment. The SCA results reveal that modafinil slows down the exocytosis process so that, the number of catecholamines released per exocytotic event is enhanced in the modafinil-treated cells. Also, IVIEC results offer an upregulation effect of modafinil on the vesicular catecholamine storage. Mass spectrometry imaging by time-of-flight secondary ion mass spectrometry (ToF-SIMS) illustrates that treatment with modafinil reduces the cylindrical-shaped phosphatidylcholine at the cellular membrane, while the high curvature lipids with conical structures such as phosphatidylethanolamine and phosphatidylinositol are elevated after modafinil treatment. Combining the results obtained by SCA, IVIEC and ToF-SIMS suggests that modafinil-treated cells release a larger portion of their vesicular content at least in part by changing the lipid composition of the cell membrane, suggesting regulation of cognition.
PubMed: 37529675
DOI: 10.1017/qrd.2021.4 -
The Cochrane Database of Systematic... May 2018Despite the high prevalence of apathy in Alzheimer's disease (AD), and its harmful effects, there are currently no therapies proven to treat this symptom. Recently, a... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Despite the high prevalence of apathy in Alzheimer's disease (AD), and its harmful effects, there are currently no therapies proven to treat this symptom. Recently, a number of pharmacological therapies have been investigated as potential treatments for apathy in AD.
OBJECTIVES
Objective 1: To assess the safety and efficacy of pharmacotherapies for the treatment of apathy in Alzheimer's disease (AD).Objective 2: To assess the effect on apathy of pharmacotherapies investigated for other primary outcomes in the treatment of AD.
SEARCH METHODS
We searched the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group (ALOIS), MEDLINE, Embase, CINAHL, PsycINFO, LILACS, ClinicalTrials.gov and the World Health Organization (WHO) portal, ICTRP on 17 May 2017.
SELECTION CRITERIA
Eligible studies were double-blind, randomized, placebo-controlled trials (RCTs) investigating apathy as a primary or secondary outcome in people with AD.
DATA COLLECTION AND ANALYSIS
Three review authors extracted data. We assessed the risks of bias of included studies using Cochrane methods, and the overall quality of evidence for each outcome using GRADE methods. We calculated mean difference (MD), standardized mean difference (SMD) or risk ratio (RR) with 95% confidence intervals on an intention-to-treat basis for all relevant outcome measures.
MAIN RESULTS
We included 21 studies involving a total of 6384 participants in the quantitative analyses. Risk of bias is very low to moderate. All studies reported appropriate methods of randomization and blinding. Most studies reported appropriate methods of allocation concealment. Four studies, three with methylphenidate and one with modafinil, had a primary aim of improving apathy. In these studies, all participants had clinically significant apathy at baseline. Methylphenidate may improve apathy compared to placebo. This finding was present when apathy was assessed using the apathy evaluation scale (AES), which was used by all three studies investigating methylphenidate: MD -4.99, 95% CI -9.55 to -0.43, n = 145, 3 studies, low quality of evidence, but not when assessed with the neuropsychiatric inventory (NPI)-apathy subscale, which was used by two of the three studies investigating methylphenidate: MD -0.08, 95% CI -3.85 to 3.69, n = 85, 2 studies, low quality of evidence. As well as having potential benefits for apathy, methylphenidate probably also slightly improves cognition (MD 1.98, 95% CI 1.06 to 2.91, n = 145, 3 studies, moderate quality of evidence), and probably improves instrumental activities of daily living (MD 2.30, 95% CI 0.74 to 3.86, P = 0.004, n = 60, 1 study, moderate quality of evidence), compared to placebo. There may be no difference between methylphenidate and placebo in the risk of developing an adverse event: RR 1.28, 95% CI 0.67 to 2.42, n = 145, 3 studies, low quality of evidence. There was insufficient evidence from one very small study of modafinil to determine the effect of modafinil on apathy assessed with the FrSBe-apathy subscale: MD 0.27, 95% CI -3.51 to 4.05, n = 22, 1 study, low quality of evidence. In all other included studies, apathy was a secondary outcome and participants were not selected on the basis of clinically significant apathy at baseline. We considered the evidence on apathy from these studies to be indirect and associated with publication bias. There was low or very low quality of evidence on cholinesterase inhibitors (ChEIs) (six studies), ChEI discontinuation (one study), antipsychotics (two studies), antipsychotic discontinuation (one study), antidepressants (two studies), mibampator (one study), valproate (three studies) and semagacestat (one study).
AUTHORS' CONCLUSIONS
Methylphenidate may demonstrate a benefit for apathy and may have slight benefits for cognition and functional performance in people with AD, but this finding is associated with low-quality evidence. Our meta-analysis is limited by the small number of studies within each drug class, risk of bias, publication bias, imprecision and inconsistency between studies. Additional studies should be encouraged targeting people with AD with clinically significant apathy which investigate apathy as a primary outcome measure, and which have a longer duration and a larger sample size. This could increase the quality of evidence for methylphenidate, and may confirm whether or not it is an effective pharmacotherapy for apathy in AD.
Topics: Alanine; Alzheimer Disease; Antidepressive Agents; Apathy; Azepines; Benzhydryl Compounds; Biphenyl Compounds; Central Nervous System Stimulants; Cholinesterase Inhibitors; Humans; Methylphenidate; Modafinil; Randomized Controlled Trials as Topic; Sulfonamides; Valproic Acid
PubMed: 29727467
DOI: 10.1002/14651858.CD012197.pub2 -
Journal of Neuroscience Research Dec 2019Four major discoveries on the function of the pedunculopontine nucleus (PPN) have significantly advanced our understanding of the role of arousal in neurodegenerative... (Review)
Review
Four major discoveries on the function of the pedunculopontine nucleus (PPN) have significantly advanced our understanding of the role of arousal in neurodegenerative disorders. The first was the finding that stimulation of the PPN-induced controlled locomotion on a treadmill in decerebrate animals, the second was the revelation of electrical coupling in the PPN and other arousal and sleep-wake control regions, the third was the determination of intrinsic gamma band oscillations in PPN neurons, and the last was the discovery of gene transcription resulting from the manifestation of gamma activity in the PPN. These discoveries have led to novel therapies such as PPN deep brain stimulation (DBS) for Parkinson's disease (PD), identified the mechanism of action of the stimulant modafinil, determined the presence of separate mechanisms underlying gamma activity during waking versus REM sleep, and revealed the presence of gene transcription during the manifestation of gamma band oscillations. These discoveries set the stage for additional major advances in the treatment of a number of disorders.
Topics: Acetylation; Animals; Arousal; Calcium Channels; Central Nervous System Stimulants; Decerebrate State; Deep Brain Stimulation; GABAergic Neurons; Gait; Gamma Rhythm; Gene Expression Regulation; Histones; Humans; Modafinil; Neurodegenerative Diseases; Parkinson Disease; Pedunculopontine Tegmental Nucleus; Protein Processing, Post-Translational; Sleep, REM; Transcription, Genetic; Wakefulness
PubMed: 30916810
DOI: 10.1002/jnr.24417 -
European Journal of Pharmacology Jan 2013Modafinil is a wakefulness-promoting agent with possible beneficial effects for the management of addiction and in psychiatric conditions, but also with abuse potential...
Modafinil is a wakefulness-promoting agent with possible beneficial effects for the management of addiction and in psychiatric conditions, but also with abuse potential of its own. The mechanism of action of modafinil remains unclear. We studied pharmacological mechanisms in the effect of modafinil on prepulse inhibition (PPI), a model of sensorimotor gating. Mice were tested in automated startle boxes after administration of modafinil and antagonist drugs. Oral administration of 100mg/kg of modafinil, but not lower doses, caused a significant reduction of PPI in C57Bl/6 mice, but not Balb/c mice. This effect of modafinil could be blocked by co-treatment with the dopamine D(2) receptor antagonist, haloperidol, and the serotonin (5-HT) 2A receptor antagonist, ketanserin, but not the 5-HT(1A) receptor antagonist, WAY100,635. At 30mg/kg, which did not influence PPI, modafinil inhibited PPI disruption caused by the dopamine transporter inhibitor, GBR12909. There was no interaction between modafinil and the serotonin transporter inhibitor, fluoxetine. There were no consistent effects of modafinil on startle amplitude. These results show that oral modafinil treatment may cause disruption of PPI in mice. This effect was strain-dependent, involving dopamine D(2) and 5-HT(2A) receptor activation, and was likely mediated by an interaction with the dopamine transporter. These results extend our insight into the behavioral effects of modafinil and could be of importance for the clinical use of this agent as they may indicate an increased risk of side-effects in conditions where PPI is already reduced, such as in schizophrenia and bipolar disorder.
Topics: Administration, Oral; Animals; Benzhydryl Compounds; Central Nervous System Stimulants; Dopamine Plasma Membrane Transport Proteins; Dose-Response Relationship, Drug; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Modafinil; Receptor, Serotonin, 5-HT2A; Receptors, Dopamine D2; Reflex, Startle; Sensory Gating; Species Specificity
PubMed: 23219987
DOI: 10.1016/j.ejphar.2012.11.041 -
Behavioural Brain Research Dec 2012Modafinil is a wake-promoting drug effective at enhancing alertness and attention with a variety of approved and off-label applications. The mechanism of modafinil is...
Modafinil is a wake-promoting drug effective at enhancing alertness and attention with a variety of approved and off-label applications. The mechanism of modafinil is not well understood but initial studies indicated a limited abuse potential. A number of recent publications, however, have shown that modafinil can be rewarding under certain conditions. The present study assessed the reinforcing properties of modafinil using conditioned place preference and locomotor sensitization in mice. Experiment 1 examined a high dose of modafinil (75 mg/kg) as well as its interactions with cocaine (15 mg/kg). Cocaine alone and modafinil co-administered with cocaine induced sensitization of locomotor activity; modafinil alone showed little or no locomotor sensitization. Animals given modafinil alone, cocaine alone, and modafinil plus cocaine exhibited a strong and roughly equivalent place preference. When tested for sensitization using a low challenge dose of modafinil, cross-sensitization was observed in all cocaine-pretreated mice. Experiment 2 examined a low dose of modafinil that is similar to the dose administered to humans and has been shown to produce cognitive enhancements in mice. Low dose modafinil (0.75 mg/kg) did not produce conditioned place preference or locomotor sensitization. Together, these results suggest that modafinil has the potential to produce reward, particularly in cocaine addicts, and should be used with caution. However, the typical low dose administered likely moderates these effects and may account for lack of addiction seen in humans.
Topics: Animals; Benzhydryl Compounds; Central Nervous System Sensitization; Central Nervous System Stimulants; Cocaine; Conditioning, Operant; Dopamine Uptake Inhibitors; Dose-Response Relationship, Drug; Drug Interactions; Female; Locomotion; Male; Mice; Mice, Inbred C57BL; Modafinil; Multivariate Analysis; Reward; Sensitivity and Specificity; Time Factors
PubMed: 22963989
DOI: 10.1016/j.bbr.2012.07.039