&gt;<i>What I&#x27;m disputing is the notion that there is a clear-cut distinction between &quot;exogenous&quot; and &quot;endogenous&quot; depression, and that one is &quot;totally unrelated&quot; to the other.</i><p>While I agree that neither exist in complete isolation, it still doesn&#x27;t preclude one from being the dominant cause.<p>Moreover, not many people would advance the same argument in regards to conditions such as schizophrenia or bipolar disorder—how clinical depression is somehow special and not deserving of the same [endogenous] understanding is beyond me.