The vast majority of these drugs seem to be pain killers (unless you count birth control). It seems to me, given that, the depression side effect is probably r

The vast majority of these drugs seem to be pain killers (unless you count birth control). It seems to me, given that, the depression side effect is probably related to the following sequence of events: 1) painkillers are given to patients in lieu of actual treatment (you can fix anything with painkillers. With a very low short-term cost and you may get lucky and get a low total cost too (ie. problem disappears by itself)) 2) body "adapts" to painkillers, and they, very slowly, become less effective over time And, boom, there comes your depression.