modafinil and cognitive function


  • Drugs
  • Updated February 27, 2019

Modafinil is a wakefulness-promoting drug used to treat excessive sleepiness due to narcolepsy, obstructive sleep apnea, or shift work sleep disorder. Sometimes it is used off-label as a cognitive enhancer. Modafinil's exact mechanism is unclear, though it affects many neurotransmitter systems in the brain. Some studies suggest it may enhance performance on complex tasks in healthy individuals; however, no long-term studies have tested whether modafinil prevents cognitive decline or dementia. Modafinil is generally considered safe for most people with minor side effects such as headache, nausea, dizziness, insomnia, and anxiety.


Modafinil may improve cognitive performance on complex tasks in healthy individuals, though no studies have examined it for long-term brain health. Our search identified:

  • 1 systematic review of 24 studies in healthy individuals
  • 1 randomized cross-over trial in chess players
  • 1 randomized controlled trial for apathy in Alzheimer's disease

Potential Benefit

No studies have examined whether modafinil can prevent cognitive decline or dementia.

One systematic review examined 24 studies in healthy individuals to determine whether modafinil improved cognitive performance on simple and complex tasks [1]. Most studies suggest that modafinil does not improve simple cognitive functions such as attention, verbal working memory, and cognitive flexibility, possibly because participants already had high baseline scores on these simple cognitive functions. Modafinil's effects on learning and memory are mixed, with some studies suggesting benefits and others suggesting no change. Most studies suggest that modafinil does not affect creativity, although others suggest modafinil may impair it. Modafinil may improve some aspects of executive function such as planning, decision-making, and fluid intelligence.

In contrast to the mixed results with simple tasks, modafinil was shown to improve performance on complex tasks based on five clinical studies included in the systematic review. It was reported to be beneficial in a learning task that also relied on attention and executive function, a task that relied on short-term memory and cognitive flexibility, and a task using multiple memory domains and attention [1]. In a different study, chess players took more time per move on modafinil compared to placebo, and therefore improved performance, but lost a number of games due to taking too much time [2].

For Dementia Patients

No studies have examined whether modafinil improves cognition in Alzheimer's patients. One study reported that modafinil did not reduce apathy in Alzheimer's patients [3].


Modafinil is generally considered safe for most people, with minor side effects such as headache, nausea, insomnia, anxiety, and dizziness. However, it may be associated with rare life-threatening skin conditions or rare psychiatric conditions [4][5]. Modafinil is preferred to other wakefulness-promoting drugs due to its lower risk of addiction, though it is still a schedule IV-controlled substance due to rare case reports of abuse. The long-term safety of modafinil is not known.

Modafinil affects an enzyme that may alter the blood concentration of some drugs such as opioids and some anti-viral medications. Check with your doctor for other drug interactions before taking modafinil.

NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.

How to Use

Modafinil is available as a prescription medicine used to improve wakefulness in individuals with narcolepsy, shift work sleep disorder, and obstructive sleep apnea. It is taken at doses of 100-200mg in the morning.

Modafinil is sold under the brand name Provigil®, though it is also available as a generic drug.

Learn More

For more information on drug interactions with modafinil, visit

Learn more from the Scientific American Mind article, "A Safe Drug to Boost Brainpower."