Effects of methylphenidate on memory functions of adults with ADHD.

Neuropsychological research on adults with attention deficit hyperactivity disorder (ADHD) revealed considerable impairments in memory functions related to executive control. However, only limited evidence exists supporting the effects of pharmacological treatment using methylphenidate (MPH) on memory functions. The aim of the present study was, therefore, to explore the impact of MPH on various memory functions of adults with ADHD. Thirty-one adults with ADHD treated with MPH, 36 adults with ADHD not-treated with MPH, and 36 healthy individuals were assessed on several aspects of memory, including short-term memory, working memory, retrospective memory, prospective memory, and source memory. Multivariate statistical analyses were applied to compare memory functions between groups. Nonmedicated adults with ADHD showed considerable impairments in memory functions related to executive control. Adults with ADHD treated with MPH showed improved memory functions when compared to nonmedicated patients, but were still impaired when compared to healthy controls. The present study emphasized the severity of memory impairments of adults with ADHD. A pharmacological treatment with MPH appeared to improve memory, but does not normalize functioning. Additional treatment intervention (e.g., cognitive-behavioral therapy) is therefore necessary.