Also worth mentioning:

Quote Originally Posted by gwahir View Post
The periodicity of my depressive moods, and the fact that they are precipitated by and connected to actual events and feelings suggest it's not chemical or biological depression.
This is why I have gone untreated for so, so long. Until very recently, my perception was "it's only depression if it's chemical, and you don't go and get treated just because you are sad". Then my friend committed suicide.