Narcolepsy is an underdiagnosed disorder of impaired wakefulness and rapid-eye-movement sleep. Symptoms include excessive daytime sleepiness, cataplexy, sleep paralysis and hypnagogic hallucinations. Disturbances of nocturnal sleep may also occur. Cataplexy is pathognomonic of narcolepsy, but does not occur in all patients; therefore, sleep tests are generally used to confirm the diagnosis. Nonpharmacological measures have a beneficial effect on symptom severity and may be sufficient in those with mild symptoms. Pharmacotherapy may include the use of CNS stimulants such as dexamfetamine or modafinil to promote wakefulness, and antidepressants to treat cataplexy.