Modafinil is a wakefulness-promoting agent. It is typically used to treat narcolepsy, sleep apnea, or shift work sleep disorder.
Shift work sleep disorder occurs when people work in a non-traditional time compromising their natural sleep-wake cycle. This can lead to excessive sleepiness during working hours and causes difficulty sleeping during the hours they want to sleep. In such a matter, Modafinil helps them stay awake and active during their shifts. It also improves their productivity.
More information: Healthmatter.co.