Department of Psychiatry, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Neuropsychopharmacology. 2013 Sep;38(10):2011-8. doi: 10.1038/npp.2013.100. Epub 2013 Apr 23.
Increased use of stimulant medication, such as methylphenidate, by healthy college students has raised questions about its cognitive-enhancing effects. Methylphenidate acts by increasing extracellular catecholamine levels and is generally accepted to remediate cognitive and reward deficits in patients with attention deficit hyperactivity disorder. However, the cognitive-enhancing effects of such 'smart drugs' in the healthy population are still unclear. Here, we investigated effects of methylphenidate (Ritalin, 20 mg) on reward and punishment learning in healthy students (N=19) in a within-subject, double-blind, placebo-controlled cross-over design. Results revealed that methylphenidate effects varied both as a function of task demands and as a function of baseline working memory capacity. Specifically, methylphenidate improved reward vs punishment learning in high-working memory subjects, whereas it impaired reward vs punishment learning in low-working memory subjects. These results contribute to our understanding of individual differences in the cognitive-enhancing effects of methylphenidate in the healthy population. Moreover, they highlight the importance of taking into account both inter- and intra-individual differences in dopaminergic drug research.
越来越多的健康大学生使用兴奋剂药物，如哌醋甲酯，引起了人们对其认知增强作用的质疑。哌醋甲酯通过增加细胞外儿茶酚胺水平起作用，通常被认为可以改善注意力缺陷多动障碍患者的认知和奖励缺陷。然而，这种“聪明药”在健康人群中的认知增强作用仍不清楚。在这里，我们在一项基于个体的、双盲、安慰剂对照的交叉设计中，研究了哌醋甲酯（利他林，20mg）对健康学生（N=19）的奖励和惩罚学习的影响。结果表明，哌醋甲酯的作用既取决于任务要求，也取决于基线工作记忆能力。具体来说，哌醋甲酯提高了高工作记忆能力受试者的奖励与惩罚学习，而降低了低工作记忆能力受试者的奖励与惩罚学习。这些结果有助于我们理解哌醋甲酯在健康人群中的认知增强作用的个体差异。此外，它们强调了在多巴胺能药物研究中考虑个体间和个体内差异的重要性。
