Pharmacological Cognitive Enhancement in Healthy Individuals: A Compensation for Cognitive Deficits or a Question of Personality?

<div><p>The ongoing bioethical debate on pharmacological cognitive enhancement (PCE) in healthy individuals is often legitimated by the assumption that PCE will widely spread and become desirable for the general public in the near future. This assumption was questioned as PCE is not equally save and effective in everyone. Additionally, it was supposed that the willingness to use PCE is strongly personality-dependent likely preventing a broad PCE epidemic. Thus, we investigated whether the cognitive performance and personality of healthy individuals with regular nonmedical methylphenidate (MPH) use for PCE differ from stimulant-naïve controls. Twenty-five healthy individuals using MPH for PCE were compared with 39 age-, sex-, and education-matched healthy controls regarding cognitive performance and personality assessed by a comprehensive neuropsychological test battery including social cognition, prosocial behavior, decision-making, impulsivity, and personality questionnaires. Substance use was assessed through self-report in an interview and quantitative hair and urine analyses. Recently abstinent PCE users showed no cognitive impairment but superior strategic thinking and decision-making. Furthermore, PCE users displayed higher levels of trait impulsivity, novelty seeking, and Machiavellianism combined with lower levels of social reward dependence and cognitive empathy. Finally, PCE users reported a smaller social network and exhibited less prosocial behavior in social interaction tasks. In conclusion, the assumption that PCE use will soon become epidemic is not supported by the present findings as PCE users showed a highly specific personality profile that shares a number of features with illegal stimulant users. Lastly, regular MPH use for PCE is not necessarily associated with cognitive deficits.</p></div

Mean z-scores and standard errors of means for the global cognitive index (GCI) and four cognitive domains.

<p>Mean z-scores and standard errors of means for the global cognitive index (GCI) and four cognitive domains.</p

Trial profile.

<p>ADHD: Attention Deficit Hyperactivity Disorder, ADHD-SR: Attention Deficit Hyperactivity Disorder Self-Rating scale, BIS-11: Barratt Impulsiveness Scale-11, CANTAB: Cambridge Neuropsychological Test Automated Battery, DD: Delay Discounting task, IDPC: Standardized Interview for Psychotropic Drug Consumption (self-report), IED: Intra-Extra Dimensional Set-Shifting, IGT: Iowa Gambling Task, LNST: Letter Number Sequencing Task, MASC: Movie for the Assessment of Social Cognition, MET: Multifaceted Empathy Test, MDMA: 3,4-Methylendioxy-N-methylamphetamin, MPH: methylphenidate, PAL: Paired Associates Learning, PCE: pharmacological cognitive enhancement, RAVLT: Rey Auditory Verbal Learning Test, RVP: Rapid Visual Information Processing, SCID I/II: Structural Clinical Interview for DSM-IV Axis I/II Disorders, SWM: Spatial Working Memory, TCI: Temperament and Character Inventory.</p

Personality traits and social cognition and interaction of stimulant-naïve healthy controls and individuals using methylphenidate for the purpose of pharmacological cognitive enhancement (PCE).

<p>Data are means and standard deviations. Significant p-values are shown in bold. BIS: Barratt Impulsiveness Scale, DD: Delay Discounting task, MACH-IV: Machiavellianism Scale, MASC: Movie for the Assessment of Social Cognition, MET: Multifaceted Empathy Test, PCE: pharmacological cognitive enhancement, SCID-II: Structural Clinical Interview for DSM-IV Axis-II Disorders, SNQ: Social network questionnaire, TCI: Temperament and Character Inventory, ToM: Theory-of-Mind.</p><p>Personality traits and social cognition and interaction of stimulant-naïve healthy controls and individuals using methylphenidate for the purpose of pharmacological cognitive enhancement (PCE).</p

Demographic characteristics and drug use of stimulant-naïve healthy controls and individuals using methylphenidate for the purpose of pharmacological cognitive enhancement (PCE).

<p>Data are means and standard deviations, or number and percent. Significant p-values are shown in bold.</p><p>^aFor cut-offs see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129805#pone.0129805.s003" target="_blank">S1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0129805#pone.0129805.s004" target="_blank">S2</a> Methods.</p><p>ADHD-SR: Attention Deficit Hyperactivity Disorder Self-Rating scale, BDI: Beck Depression Inventory, IQ: intelligence quotient, MWT-B: Mehrfachwahl-Wortschatz-Test (vocabulary test), PCE: pharmacological cognitive enhancement.</p><p>Demographic characteristics and drug use of stimulant-naïve healthy controls and individuals using methylphenidate for the purpose of pharmacological cognitive enhancement (PCE).</p

Means and standard error of means of points gained and of processing time (sec) in the Iowa Gambling Task (IGT).

<p>** <i>p</i>< 0.010, and ***<i>p</i> < 0.001.</p