I was convinced antidepressants wouldn't work when i tried them. If the pills were no better then placebo capsules, the power of my disbelief most likely would have rendered them useless. But they kicked in at 4 weeks(doctor said it would take 6 weeks) lifting away much of the internal blackness. Pills worked for about 18 months, tolerance built up. Suffered major negative symptom around then as well, so refused to switch to different drug. this was about 8 years ago. Drug was Zoloft. I would not advise long term use. But in extreme cases in which prolonged mind producing pain causes the wish for death, one or two antidepressants should be tried with the express goal of gaining a 4 to 6 month window of alleviated mood, and using that time with maximum effort in trying to improve the situation that causes the depression--that is, if it is a situation that is possible to change.
I'm not trying to say they are useless. I have seen plenty of people greatly helped by SSRIs (I work as a psychotherapist). Depressed folks respond to placebo at a higher rates that other populations with mental health problems. However, that does not minimize the medications value to the 30%+ who are genuinely helped by SSRIs. My point was to question whether these results had any value towards divining the underlying cause of depression.