Yes, depression is basically curable. In the more common variant of the depressive illness episodes occur, which subside spontaneously and end in the overwhelming majority of those affected with a complete healing. In some people, the depression never returns.
Our 10 most important tips against depression
But you can not and should not rely on that. It is more likely that the inclination or susceptibility ("vulnerability") to the development of a renewed episode - even in a different appearance - will last a lifetime. Therefore, everything should be done to minimize the risk of relapse by taking appropriate measures. In addition to medicines (phase prophylactics), especially their own "psycho-hygiene" is of crucial importance. Cognitive-behavioral therapy or other forms of psychotherapeutic help can successfully support this process.
Chronic depression over years has less chance of complete recovery. But even those affected can be helped with effective treatment options today.