Effects of modafinil on non-verbal cognition, task enjoyment and creative thinking in healthy volunteers

Abstract

Background: Modafinil, a putative cognitive enhancing drug, has previously been shown to improve performance of healthy volunteers as well as patients with attention deficit disorder and schizophrenia, mainly in tests of executive functions. The aim of this study was to investigate the effects of modafinil on non-verbal cognitive functions in healthy volunteers, with a particular focus on variations of cognitive load, measures of motivational factors and the effects on creative problem-solving.

Methods: A double-blind placebo-controlled parallel design study evaluated the effect of 200 mg of modafinil (N = 32) or placebo (N = 32) in non-sleep deprived healthy volunteers. Non-verbal tests of divergent and convergent thinking were used to measure creativity. A new measure of task motivation was used, together with more levels of difficulty on neuropsychological tests from the CANTAB battery.

Results: Improvements under modafinil were seen on spatial working memory, planning and decision making at the most difficult levels, as well as visual pattern recognition memory following delay. Subjective ratings of enjoyment of task performance were significantly greater under modafinil compared with placebo, but mood ratings overall were not affected. The effects of modafinil on creativity were inconsistent and did not reach statistical significance.

Conclusions: Modafinil reliably enhanced task enjoyment and performance on several cognitive tests of planning and working memory, but did not improve paired associates learning. The findings confirm that modafinil can enhance aspects of highly demanding cognitive performance in non-sleep deprived individuals. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

Fig. 1

One-touch Stockings of Cambridge (SOC) spatial planning task mean choice to correct. Subjects on modafinil made significantly fewer choices (p = 0.002) to achieve the correct answer than those on placebo, particularly at the harder (6 moves). Error bars represent the SEM.

Fig. 2

Effect of drug on spatial working memory. Subjects on placebo made significantly more between search errors on the difficult 10-box problems (p < 0.05). Error bars represent the SEM.