Many consider olanzapine to be more effective than other antipsychotics and just below clozapine in overall efficacy. Its strong effectiveness, once-daily dosing, and low QT-prolongation risk are appealing.

Methadone is a long-acting opioid and a mainstay of opioid use disorder (OUD) treatment.

Buprenorphine (Subutex, available now only as generic) is the active ingredient in Suboxone (buprenorphine/naloxone) and is responsible for the effectiveness of the combination medication in opioid use disorder. 

Light therapy is an effective treatment for seasonal affective disorder and possibly for nonseasonal depression as well. 

Tasimelteon is a melatonin receptor agonist approved for non-24-hour sleep-wake disorder (N24SWD), which occurs primarily in blind people.

Pitolisant is the only noncontrolled substance approved for narcolepsy, but limited experience and higher cost make it a second-line option after modafinil and armodafinil.

Solriamfetol is a wakefulness promoter with a different mechanism of action (dopamine and norepinephrine reuptake inhibition) from modafinil and armodafinil.

Melatonin is a hormone secreted by the pineal gland that helps regulate the sleep-wake cycle.

While modafinil can be helpful for many causes of excessive sleepiness, realize that many people end up using it off-label for lifestyle enhancement, such as working, studying, and partying.