I don't know that there is any drug or intervention that prevents depression in otherwise healthy people, besides eating a balanced diet, maintaining a healthy

I don't know that there is any drug or intervention that prevents depression in otherwise healthy people, besides eating a balanced diet, maintaining a healthy weight, and getting sufficient exercise. Preventing relapse in people whose depression is in remission may be a different story (and, one which I'm not terribly familiar with). Part of the problem is that the placebo effect in trials for depression is very strong. See, for instance https://pubmed.ncbi.nlm.nih.gov/24172161/ https://pubmed.ncbi.nlm.nih.gov/24172161/ BTW, I am also a lifelong sufferer of depression. SSRIs have never really done anything for me, but bupropion has been a lifesafer.