Subjective Effects Of Methylphenidate Research Articles

Is Methylphenidate Beneficial and Safe in Pharmacological Cognitive Enhancement?

Nootropics are drugs used to either treat or benefit cognition deficits. Among this class, methylphenidate is a popular agent, which acts through indirect dopaminergic and noradrenergic agonism and, therefore, is proposed to enhance performance in catecholamine-dependent cognitive domains such as attention, memory and prefrontal cortex-dependent executive functions. However, investigation into the efficacy of methylphenidate as a cognitive enhancer has yielded variable results across all domains, leading to debate within the scientific community surrounding its off-label use in healthy individuals seeking scholaristic benefit or increased productivity. Through analysis of experimental data and methodological evaluation, it is apparent that there are dose-, task- and domain-dependent considerations surrounding the use of methylphenidate in healthy individuals, whereby tailored dose administration is likely to provide benefit on an individual basis dependent on the domain of cognition in which benefit is required. Additionally, it is apparent that there are subjective effects of methylphenidate, which may increase user productivity irrespective of cognitive benefit. Whilst there is not extensive study in healthy older adults, it is plausible that there are dose-dependent benefits to methylphenidate in older adults in selective cognitive domains that might improve quality of life and reduce fall risk. Methylphenidate appears to produce dose-dependent benefits to individuals with attention-deficit/hyperactivity disorder, but the evidence for benefit in Parkinson's disease and schizophrenia is inconclusive. As with any off-label use of pharmacological agents, and especially regarding drugs with neuromodulatory effects, there are inherent safety concerns; epidemiological and experimental evidence suggests there are sympathomimetic, cardiovascular and addictive considerations, which might further restrict their use within certain demographics.

Similar and Different? Subjective Effects of Methylphenidate and Cocaine in Opioid-Maintained Patients

ABSTRACTMethylphenidate (MPH) is commonly prescribed for attention deficit hyperactivity disorder (ADHD). Recreational nonmedical use has been described and also occurs in patients on opioid maintenance treatment (OMT). MPH has been proposed for use as replacement therapy in cocaine dependence, although evidence for efficacy is inconclusive. We conducted a cross-sectional interview study on patterns of MPH use in a sample of 20 MPH-using patients on OMT with a history of cocaine use. We assessed symptoms of depression, ADHD during childhood, and retrospective subjective-effects profiles of MPH and cocaine. Risky patterns of MPH use were common, in particular illicit acquisition, use of high doses, and parenteral administration. Sixty percent of patients reported having used MPH as a substitute for cocaine. Correspondingly, the subjective-effect profiles of MPH and cocaine showed striking parallels, with overall effects of MPH being rated more positively than those of cocaine. Proportions of patients with elevated scores for depression or childhood ADHD were large, highlighting the importance of treating dual disorders in this population. Clinical studies on MPH substitution in cocaine-dependent patients on opioid maintenance treatment could benefit from consideration of the patterns of application of MPH in this population. Results are preliminary due to small sample size.

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

BackgroundCocaine use continues to be a public health problem, yet there is no proven effective pharmacotherapy for cocaine dependence. A promising approach to treating cocaine dependence may be agonist-replacement therapy, which is already used effectively in the treatment of opioid and tobacco dependence. The replacement approach for cocaine dependence posits that administration of a long-acting stimulant medication should normalize the neurochemical and behavioral perturbations resulting from chronic cocaine use. One potential medication to be substituted for cocaine is methylphenidate (MPH), as this stimulant possesses pharmacobehavioral properties similar to those of cocaine.AimTo provide a qualitative review addressing the rationale for the use of MPH as a cocaine substitute and its clinical potential in the treatment of cocaine dependence.MethodsWe searched MEDLINE for clinical studies using MPH in patients with cocaine abuse/dependence and screened the bibliographies of the articles found for pertinent literature.ResultsMPH, like cocaine, increases synaptic dopamine by inhibiting dopamine reuptake. The discriminative properties, reinforcing potential, and subjective effects of MPH and cocaine are almost identical and, importantly, MPH has been found to substitute for cocaine in animals and human volunteers under laboratory conditions. When taken orally in therapeutic doses, its abuse liability, however, appears low, which is especially true for extended-release MPH preparations. Though there are promising data in the literature, mainly from case reports and open-label studies, the results of randomized controlled trials have been disappointing so far and do not corroborate the use of MPH as a substitute for cocaine dependence in patients without attention deficit hyperactivity disorder.ConclusionClinical studies evaluating MPH substitution for cocaine dependence have provided inconsistent findings. However, the negative findings may be explained by specific study characteristics, among them dosing, duration of treatment, or sample size. This needs to be considered when discussing the potential of MPH as replacement therapy for cocaine dependence. Finally, based on the results, we suggest possible directions for future research.

Normalizing Effects of Modafinil on Cocaine-Induced Sleep Abnormalities

Normalizing Effects of Modafinil on Cocaine-Induced Sleep Abnormalities

Reinforcing and subjective effects of methylphenidate in adults with and without attention deficit hyperactivity disorder (ADHD)

There has been controversy over the abuse potential of methylphenidate (MPH) in the context of treatment for attention deficit hyperactivity disorder (ADHD). The objective of this study was to compare the reinforcing and subjective effects of oral MPH in adults with and without ADHD. Following screening, 33 adults (n = 16 with ADHD; n = 17 free from psychiatric diagnoses) completed four pairs of experimental sessions, each of which included a sampling session and a self-administration session. During sampling sessions, subjects received in randomized order 0 (placebo), 20, 40, and 60 mg MPH. During self-administration sessions, subjects completed a progressive ratio (PR) task to earn portions of the dose received on the corresponding sampling session. Subjective effects were recorded throughout all sessions. The main outcome measure for the study was the number of ratios completed on the PR task. Secondary measures included peak subjective effects and area-under-the-curve values for subjective effects. Compared to the control group, the ADHD group completed more ratios on the PR task. Both groups showed robust effects of methylphenidate on subjective endpoints. Main effects of group were noted on subjective effects involving concentration and arousal. Compared to placebo, MPH produced reinforcing effects only for the ADHD group and not for the control group. Increases in stimulant-related subjective effects in non-ADHD subjects were not associated with drug reinforcement.

Assessing the abuse potential of methylphenidate in nonhuman and human subjects: a review

Methylphenidate (MPH) is widely used for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in children, adolescents, and adults. Methylphenidate is clearly effective for the treatment of ADHD, but there is controversy as to whether it has significant abuse potential like other psychostimulants (e.g., d-amphetamine and cocaine). In general, the drug is believed to be abused at rates much lower than those for other stimulants. The present review examines studies that investigated the behavioral pharmacological profile of methylphenidate and discusses how results from these studies address its abuse liability. Using MEDLINE search terms methylphenidate, drug discrimination, reinforcement, self-administration, subjective effects, subject-rated effects, abuse potential, and abuse liability, along with a review of the references from identified articles, 60 studies were located in which the reinforcing, discriminative-stimulus, or subjective effects of methylphenidate were directly assessed in nonhumans or humans. Forty-eight (80.0%) of the studies reviewed indicate that methylphenidate either functions in a manner similar to d-amphetamine or cocaine (e.g., functions as a reinforcer, substitutes fully in drug discrimination experiments), or produces a pattern of subjective effects suggestive of abuse potential. The results are discussed as they pertain to factors that may account for the apparent discrepancy in abuse rates between methylphenidate and other stimulants, including characterization of actual abuse rates, defining abuse and misuse, pharmacokinetic factors, and validity of abuse liability assays.

Sleepiness and the reinforcing and subjective effects of methylphenidate.

Sleepiness and the reinforcing and subjective effects of methylphenidate.

Reinforcing and subjective effects of methylphenidate in humans.

This study assessed the reinforcing and subjective effects of methylphenidate in a group of 35 adults (15 females and 20 males) with no history of drug dependence. A discrete-trial choice procedure was used to assess the reinforcing effects of a single oral dose of methylphenidate selected to produce a moderate subjective response in each subject (range 20-40mg). A number of variables (gender, current and past drug use, personality, and baseline mood and arousal) were examined in an attempt to identify sources of variability in drug response. Methylphenidate was chosen on 28% of occasions. In the group as a whole, methylphenidate had no effect on ratings of drug liking, but did increase ratings indicative of "positive" mood, CNS stimulation and anxiety. Within-subject variability in methylphenidate choice was related to variability in subjective response to the drug across choice trials. Methylphenidate choice was also associated with between-subject differences in prior opioid use and several personality dimensions. When compared with the results of a prior study of the same design with d-amphetamine, these results suggest that methylphenidate produces a somewhat different profile of subjective effects, and may be a less efficacious reinforcer than d-amphetamine.