Methylphenidate produces selective enhancement of declarative memory consolidation in healthy volunteers

Abstract

RationaleMethylphenidate inhibits the reuptake of dopamine and noradrenaline and is used to treat children with attention deficit hyperactivity disorder (ADHD). Besides reducing behavioral symptoms, it improves their cognitive function. There are also observations of methylphenidate-induced cognition enhancement in healthy adults, although studies in this area are relatively sparse. We assessed the possible memory-enhancing properties of methylphenidate.ObjectiveIn the current study, the possible enhancing effects of three doses of methylphenidate on declarative and working memory, attention, response inhibition and planning were investigated in healthy volunteers.MethodsIn a double blind placebo-controlled crossover study, 19 healthy young male volunteers were tested after a single dose of placebo or 10, 20 or 40 mg of methylphenidate. Cognitive performance testing included a word learning test as a measure of declarative memory, a spatial working memory test, a set-shifting test, a stop signal test and a computerized version of the Tower of London planning test.ResultsDeclarative memory consolidation was significantly improved relative to placebo after 20 and 40 mg of methylphenidate. Methylphenidate also improved set shifting and stopped signal task performance but did not affect spatial working memory or planning.ConclusionsTo the best of our knowledge, this is the first study reporting enhanced declarative memory consolidation after methylphenidate in a dose-related fashion over a dose range that is presumed to reflect a wide range of dopamine reuptake inhibition.

A Combination of Nootropic Ingredients (CAF+) Is Not Better than Caffeine in Improving Cognitive Functions

“…On the other hand, it may reasonably be expected that a cognition enhancer would also be able to improve cognition in such a population. This was demonstrated in two studies examining the effects of the cognitive enhancer methylphenidate in healthy young volunteers: methylphenidate was found to decrease response times and improve episodic memory in one study (Linssen et al 2014) and to improve declarative memory, attention, and response inhibition in another study (Linssen et al 2012). We did find some effects of caffeine, although it must be mentioned that absolute differences were relatively small.…”

Patterns of non-medical use of methylphenidate among 5th and 6th year students in a medical school in southern Brazil

“…12 Among those who used such substances, MPH was the drug of choice, accounting for 62% of the total. Evidence has suggested that MPH improves executive functions and memory in healthy individuals 13 ; some authors advocate its use, legalization and even the encouragement of such use. 12,14,15 However, the use of MPH for cognitive enhancement is controversial, because neither drug efficacy nor the benefit-risk balance provide sufficient evidence for this use.…”

Declarative Memory

“…Three were investigating single doses of d-amphetamine of which all three reported positive effects on delayed recall or recognition (Zeeuws et al 2010a, b;Zeeuws and Soetens 2007). Four were investigating single doses of methylphenidate of which two reported positive effects on delayed recall memory (Izquierdo et al 2008;Linssen et al 2012) and two found no difference (Hermens et al 2007;Kuypers and Ramaekers 2005). The studies that reported positive effects had in common that they were using considerably longer word lists (20, 30, 70 words) opposed to the studies not reporting positive effects (12 and 15 words) and were looking at late stage memory consolidation.…”