Depression is a symptom, not a disease. If the underlying cause is long-lasting, then you're stuck on the meds forever e.g. bipolar disorder is a chronic diseas

Depression is a symptom, not a disease. If the underlying cause is long-lasting, then you're stuck on the meds forever e.g. bipolar disorder is a chronic disease and requires mood stabilizers (and, in type II, antidepressants) to be taken indefinitely. But in the case of treatable or temporary conditions like PTSD, anti-depressants can just be used to reduce symptoms while other treatments are under way. Major Depressive Disorder is a specific disease that's commonly called "depression", and I have no idea what the long-term treatments look like there.