visagrunt wrote:
I have never been clinically depressed (to my knowledge), and I have a shopping list of signs to watch for. That leads me to speculate: what comes first, the depression, or the personal circumstances that appear to be linked to it.
I am lonely --> I am sad about that --> I am depressed, therefore I am depressed because I am lonely. This suffers from the fallacy post hoc ergo propter hoc.
What if, on the other hand, depression is a latent biochemical circumstance, which is lying dormant waiting for a trigger? The loneliness doesn't cause the depression, but rather 'flips the switch' in the brain. So if it wasn't one thing, it would just as likely be another.
Such a pathology might account for some comorbidity, and would also support the expectation that if you have been depressed before you are at greater risk for being depressed again.
Is the "post hoc ergo propter hoc" similar to "correlation does not imply causation"? I like logic, but it takes some thinking on my part.
Your theory regarding the "latent biochemical circumstance" is interesting and similar to a theory that I heard in college. It's referred to as the "Stress diathesis model". You might of already heard of it, but it basically states that there are biological predispositions that when exposed to critical stress, provide the right combination to produce depression...or another mental illness. This was also proposed for Schizophrenia.