Modalert 200 mg (modafinil) is used to wake up people with narcolepsy, shift work sleep disorder, and OSA. Its effectiveness in treating Delayed Sleep Phase Syndrome (DSPS) is unclear. DSPS is a circadian rhythm condition that delays sleep by two or more hours, making it hard to get up. Modafinil may improve alertness during waking hours, but it doesn't fix DSPS's circadian misalignment. Modafinil may be used off-label to assist DSPS sufferers stay awake throughout the day. This method doesn't fix the delayed sleep phase. Modafinil may not help DSPS, according to anecdotes and research.