Depends on a source of depression - some people may have genetic issues with serotonin path (just like ADHD people have with dopamine, or diabetics with insulin

Depends on a source of depression - some people may have genetic issues with serotonin path (just like ADHD people have with dopamine, or diabetics with insulin). Fortunately anti-depressants help out with this. There is a nice book, "Listening to prozac", written by a psychiatrist who originally believed everything can be cured by therapy, but finally admitted that some people need to stay on anti-depressants for the whole life, since the source of their depression is neurologic.