I don't believe that anti-depressants target serotonine, research doesnt support the idea that serotonine causes depression. What the anti-depressants are likely to target is the adrenals. The adrenals affect our blood pressure, and even how the thyroid hormones work, so they also affect our mood. They also affect when we are able to sleep, too low/high cortisol means no sleep. I wonder whether people going off anti-depressants suffer from screwed adrenal activity, e.g. too high cortisol.