Studies have shown that the Modafinil improves reaction time in sleep-deprived people. It also enables people to perform better on tests of neurological behavior, including grammatical reasoning and visual search. Many of these tests were done in simulated military combat situations, and the test patients report feeling less sleepy when they have taken the drug.

One aspect of studies like these is that there is both an objective and a subjective component to cognitive performance, and both are measured in sleep studies. Modafinil appears to improve wakefulness in both components.

Modafinil is sold around the world under the following brand names: Alertec®; APO-Modafinil, Activigil; Alertex, Modasomil, Modavigil, Modiodal, Provigil, Vigia, Vigicer, and Vigil.

Compared to amphetamines, Modafinil results in less of a disturbance in sleep during the “rebound” period after the drug wears off and the person resumes natural sleep. The duration of required recovery sleep is also less. Negative effects of the drug include decreased efficiency of communication, and possibly subjective estimates of cognitive ability (by the person on the drug.)

Modafinil’s full name is 2-[(diphenylmethyl)sulfinyl] acetamide. Molecular formula is C15H15NO2S.

Modafinil’s mechanism of action is undetermined, although it is known to be different from that of central nervous system stimulants. It does not act as a direct or indirect dopamine receptor agonist. It does not bind to receptors for dopamine, serotonin, GABA, or norepinephrine uptake.

Modafinil usually produces fewer adverse side effects than stimulants like amphetamines. These negative consequences of amphetamines include bodily agitation and trouble sleeping when the patient is allowed to sleep.

For a long time, scientists believed modafinil differed from Ritalin and the amphetamines partly in that modafinil did not act as a dopamine receptor agonist. Althouth modafinil works even only on people with intact alpha-adregergic systems, the drug is not an andregenic agonist. Like these other drugs, modafinil increases c-fos expression levels, but in only the subcortical regions such as the anterior hypothalamus and amygdala nucleus.

Modafinil activates oxerin-containing neurons. Neurons in the lateral hypothalamus produce orexin-A and orexin-B. These are neuropeptides of 33 amino acids and 28 amino acids respectively.

The Food and Drug Administration has mandated a warning be added for modafinil about the potential for rashes and psychiatic symptoms. Doctors were cautioned about giving the drug to people with psychiatric conditions.