The drug modafinil, which was developed to treat narcolepsy (excessive sleeping), appears to enhance some cognitive functions according to a new randomized double-blind study published in Neuropsychopharmacology.
“An essential function of executive processes is the cognitive control of interferences by distracting and conflicting information to facilitate goal-directed behavior in everyday life,” said study author Benjamin Becker, a professor at the University of Electronic Science and Technology of China and member of the neuSCAN Lab.
“Impairments in this cardinal cognitive domain have been demonstrated across major psychiatric disorders such as depression, and often persist after recovery thus leading to long-term impairments in everyday life. The conventional psychopharmacological treatments often allow to control the affective symptoms of psychiatric disorders, yet do not improve the cognitive deficits.”
“During recent years pharmacological means to enhance cognitive performance (via cognitive enhancers, a.k.a. neuroenhancers) have been increasingly advocated as novel strategy to improve cognitive functioning in psychiatric disorders. Accumulating evidence suggests that modafinil – an approved medication for narcolepsy – can improve cognitive control in healthy subjects and psychiatric patients,”
“However, cognitive control regulates not only other cognitive functions but also emotional functions. For instance, emotional conflict processing is vital for everyday life, such that threatening or social-emotional stimuli convey important information to redirect our attention and effects of cognitive enhancers on these emotional processes may interfere with everyday functioning,” Becker explained.
In the study, 72 healthy, male participants were randomly assigned to receive either 200 mg of modafinil or placebo before completed assessments of cognitive and emotional conflict processing. The researchers also used functional magnetic resonance imaging (fMRI) to monitor their brain activity during the tasks.
“We found that, compared to placebo, modafinil specifically enhanced cognitive conflict performance and concomitantly increased activation in the inferior frontal gyrus and its functional communication with the dorsomedial prefrontal cortex. Both prefrontal brain regions are key nodes in the cognitive control network and higher activation in these regions may underpin the improved control of cognitive conflict after modafinil administration,” Becker told PsyPost.
“In contrast, we did not observe effects of modafinil on emotional conflict processing, suggesting highly specific effects on cognitive conflict processing. We additionally assessed whether modafinil affected the subjective perception of performance via ratings and a metacognitive task and found that modafinil enhanced objective cognitive performance but did not affect subjective performance perception or affective state.”
Jialin Li, the first author of the study, added that “this is particular interesting because the lack of effects of modafinil on subjective experience suggests that it does not simply promote self-confidence or motivation but cognitive performance.”
“Overall, our findings suggest that modafinil has the potential to enhance cognitive control processes while leaving emotional processes unaffected. The pattern of cognitive enhancing effects in the absence of effects on affective process suggests a promising candidate to selectively improve cognitive control in healthy and clinical populations,” Becker said.
Future research should examine the drug’s effects in women and those with cognitive deficits, he added.
Modafinil has been used by students to boost their ability to study and improve their chances of exam success. But the drug’s overall effectiveness as a cognitive enhancer is still unclear.
“The overarching aim of our study was to determine whether modafinil might be a suitable adjunct treatment to enhance cognitive control in neuropsychiatric patients. However, putative cognitive enhancers including modafinil are increasingly used as ‘smart drugs’ by healthy individuals in lifestyle contexts or to enhance performance in academic or other competitive contexts,” Becker said.
“Whereas our findings suggest a promising potential of modafinil to selectively enhance cognitive performance while not affecting emotional processes, effects of longer-term use and potential detrimental effects in other domains remain unknown.”
The study, “Modafinil enhances cognitive, but not emotional conflict processing via enhanced inferior frontal gyrus activation and its communication with the dorsomedial prefrontal cortex“, was authored by Jialin Li, Xi Yang, Feng Zhou, Congcong Liu, Zhenyu Wei, Fei Xin, Bianca Daumann, Jörg Daumann, Keith M. Kendrick, and Benjamin Becker.
