I doubt that it will profit you much to pursue this line of reasoning. The problem is not that different "conditions" may resemble depression but that the treatments, such as antidepressants (ADs), are themselves so non-specific in what they can be used for. ADs are used to treat anxiety for one thing, OCD for another. They sometimes help with ADD and I've even seen them used for Tinnitis! This profound lack of specificity at the treatment end does not bode well for any attempts to correlate specific drugs with specific types of "depression" since neither group is in any way adequitely understood.