How Effective are Pharmaceuticals for Cogntitive Enhancement in Healthy Adults? - Roberts et al. - 2020 - Article

How Effective are Pharmaceuticals for Cogntitive Enhancement in Healthy Adults? A Series of Meta-Analyses of Cognitive Performance during Acute Administration of Modafinil, Methylphenidate and D-Amphetamine - Roberts et al. - 2020

What is this article about?

The topic of this article is cognitive enhancers and how they affect cognitive abilities. Psychoactive medications are used as part of cognitive improvement initiatives, primarily in the context of education and employment, to boost cognitive capacities in healthy individuals. Perhaps as a result of media reports suggesting widespread use among college students, the popularity and expectations for the efficacy of these medications have grown. Although prevalence studies vary, evidence indicates that the use of cognitive enhancers is likely to rise in demanding academic and employment environments. Modafinil, methylphenidate, and D-amphetamine are the three medications that are most frequently used to improve cognitive functions. 

National drug and medicine controls apply to these medications because they are used to treat medical problems like ADHD and narcolepsy. Although modafinil is thought to have less abuse potential than D-amphetamine and methylphenidate, it is currently unknown how exactly these three drugs work to enhance cognition. Although there is a wealth of experimental data evaluating the effects of cognitive enhancers on neurocognition, the results are highly heterogeneous, making it challenging to interpret their overall effectiveness. Whether these medications enhance or impair performance in particular cognitive domains has been the subject of various research with variable degrees of success. There have been meta-analyses to examine the effectiveness of modafinil and MPH on various cognitive domains, but none have examined the individual impacts of all three medicines.In course of this study, the nature and extent of modafinil, methylphenidate and D-amphetamine on executive functions, such as inhibitory control, long term memory, recall and selective attention.

How was the study conducted?

The study started with a literature search, searching through electronic databases. Afterwards, the studies found online were compared, scanned and checked for eligibility.Studies about inhibitory control, switching, access to semantic/long-term memory, updating, spatial working memory, recall selective attention and sustained attention.

What were the results of this study?

After conducting searches on multiple databases, the researchers identified 878 potential papers, which were narrowed down to 110 after reviewing titles and abstracts. Further exclusions were made based on titles and availability of necessary data, resulting in a final analysis of 47 articles. The study provides information about the sample sizes, dose, and participant characteristics of all studies included in their analyses. Cognitive testing was typically carried out 90-150 minutes after drug administration, with mean participant ages varying across different drug types. The gender distribution varied across studies, with some having all-male samples and others having a higher percentage of female participants.


A meta-analysis of studies on the effects of methylphenidate (MPH), the pharmaceutical ingredient in Ritalin, has found that the drug can enhance memory, though the effect is modest. The same study also concluded that MPH had an effect on inhibitory control in healthy adults. However, it remains unclear whether these findings would translate into increased productivity. The use of MPH by students during exam time has been controversial. In the US, in particular, concerns have been raised over students using ADHD as a pretext to gain a prescription for the drug.


A study has found that modafinil, a drug used to treat sleep disorders, has a positive effect on the updating component of executive function. This is likely due to increases in cortical activation in the prefrontal cortex caused by modafinil. Unlike typical psychostimulants, modafinil has a reduced potential for abuse and adverse cardiovascular effects, making it popular for cognitive enhancement in healthy individuals.

What is the conclusion of this study?

Overall, MPH has the strongest, of the three studies enhancers, effects on cognition. However, MPH also has the strongest abuse potential. Modafinil however has a lower abuse potential but with risk to neurological problems when overdoeses.

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