Trazodone remains an FDA-approved option for major depressive disorder, though it is prescribed for this purpose less often today than newer-generation antidepressants — largely because of its sedating side-effect profile at the doses needed for a full antidepressant effect.
Treatment typically starts at 150 mg/day in divided doses, increasing by 50 mg/day every 3 to 4 days as tolerated, up to 400 mg/day for most outpatients. Full antidepressant benefit usually takes several weeks to become apparent, similar to other antidepressants — this isn't unique to trazodone.
Because sedation is so common at these doses, many prescribers shift most of the daily dose to bedtime. Some people also use trazodone as an add-on to another antidepressant rather than as the sole treatment.