The idea that depression has multiple causal factors has been the consensus for a long time; drug companies briefly pushed the serotonin hypothesis to sell SSR

The idea that depression has multiple causal factors has been the consensus for a long time; drug companies briefly pushed the serotonin hypothesis to sell SSRIs and some poorly-informed clinicians believed their marketing materials, but the overwhelming scientific opinion is that depression is the product of a mixture of genetic, neurological, cognitive and social factors. In the research community (but not necessarily in clinical practice), it is readily acknowledged that depression can be caused (or at least triggered) by a variety of biological factors such as comorbid diseases, malnutrition, brain injuries and drug side-effects. Sapolsky's perspective is somewhat fringe, mostly because he's a neuroendocrinologist rather than a psychiatrist. His perspective reflects his research interests rather than a broader clinical perspective. I can't say that I'm hugely familiar with his work, but I'm not sure how much of it is actually clinically relevant.