Suicidal behavior might be a distinct condition one day. The article elaborates, though I don’t know to what extent to trust the synopsis. The idea is that unipolar or bipolar depression might not explain all people who have persistent thoughts or attempts of suicide.
I’ve wondered as well who but someone in the throes of depression would commit suicide. Certainly, there’s “logical suicide”: someone taking his life before capture and punishment (Hitler committed suicide rather than face imprisonment by the Allies; some people choose euthanasia due to painful chronic illness). In the heat of rage, some people choose “suicide by cop,” though this falls into the “punishment avoidance” scenario; such people might have a clinical disorder, but not necessarily anything related to depression.
So who commits suicide outside of “logical suicide”? My suspicion is that this boils down to semantics. Research that suggests that some people commit suicide without previous diagnosis of depression could be explained away easily: they hid their depression well and committed suicide before ever being diagnosed, and there was insufficient evidence to conclusively give such a diagnosis.
My thought on this is that people commit suicide to avoid actual or perceived future pain. Even in the agony of depression, most people would hold off on suicide if they still had hope for the future. If there’s a chance that the future will hold something better than the present, then there’s no need to permanently end one’s life, as the pain is temporary. But if the pain will go on and on, then perhaps suicide isn’t so “illogical” after all.
One thing I’ve wondered is if a viable means of committing suicide might make someone feel better. In other words, if I knew for sure that taking a certain concoction of pills would end my life, might I feel better, and then be less likely to kill myself? This is controversial, as anything that seems to promote self-harm will always spark controversy. But a sense of control is very likely to cause an improvement in one’s mood. Hence, the perceived capacity to successfully carry out a suicide might actually improve one’s mood and decrease the desire to commit the act at all.
One reason why being involuntarily committed (to a psychiatric institution) might tragically backfire is that the feeling of control is lost in the person committed. The feeling of imprisonment and loss of controlling even one’s basic freedoms is traumatic for anyone, even more so for someone with clinical depression.
This isn’t to say that forced entries to mental hospitals is a bad idea or that availability of suicide pills is a good idea. The point is that loss of control can exacerbate an existing psychiatric condition and a perceived increase in control can greatly decrease the desire to end one’s life.