While a lot of depression in PWP's is situational, there is a chemical relationship as well. In one of the threads a year or two ago, someone reported (Keith -- was it you?) that dopamine is one of the precursors to seretonin, which is implicated in depression.

My situation sounds a lot like RLSmi's - I've been on antidepresssant & anti-anxiety meds steady since 1992, and periodically before that. I would love to get off of them, but I've tried in the past and the results have been as close to disastrous as I want to get.

My cyclic depressions started when I was 17, and ever since then have been getting deeper, longer and harder to climb out of - the last one lasting 12 years - and I'm stable now only with the aid of pills. 50 years ago, I would be sitting in some cold, mildewy asylum or other at this point. I am convinced that the cyclic clinical depression happened on its own, but by 1992 the fall in dopamine production was already underway, though I was not symptomatic at that time. the PD deficits were starting to affect things, and by 97 showing symptoms (whch I ignored until 2004).

However, all of this is academic, because whatever sets it off, the range of treatments and their degree and length are pretty much the same for both situational and clinical depression. If it is situational, a patient needs to keep track of when things look bright again; it may be possible to cut out some of the meds when you reach that blessed state. Cognitive behavioral therapy works well with situational fdepression, and not as much with clinical depression.

Good luck, hope this is helpful.