The drug Modafinil helps people stay awake. It is used to treat narcolepsy, too much sleep, sleep apnea, and shift work sleep disorder. Off-label, people often use modafinil to help them think better. The effects of modafinil last longer than the effects of other drugs. The half-life of modafinil is between 12 and 15 hours, but how the drug is broken down depends on things like genes and how...