As someone who has overcome the debilitating effects of Depression of years standing, it was only via targeted nutrition that it was eradicated, despite other therapies currently in vogue.
Talk-therapy counts for little, and I know of many others who have had the same experience; they found that their Depression was alleviated by nutrition and nutrition alone.
Nutrition is the foundation on which to effect a cure, and only if this fails, which is highly unlikely, will talk-therapy be of any benefit whatsoever.