The one question everyone has asked without exception, that they ache to have answered more than any other, is simply: why? Why did their friend, child, parent, spouse, or sibling take their own life? Even when a note explaining the reasons is found, lingering questions usually remain: yes, they felt enough despair to want to die, but why did they feel that? A person’s suicide often takes the people it leaves behind by surprise, only accentuating survivor’s guilt for failing to see it coming.

In general, people try to kill themselves for five reasons:

They’re depressed. This is without question the most common reason people commit suicide. Severe depression is always accompanied by a pervasive sense of suffering as well as the belief that escape from it is hopeless. The pain of existence often becomes too much for severely depressed people to bear. The state of depression warps their thinking, allowing ideas like, “Everyone would all be better off without me” to make rational sense. They shouldn’t be blamed for falling prey to such distorted thoughts any more than a heart patient should be blamed for experiencing chest pain: it’s simply the nature of their disease.

They’re psychotic. Malevolent inner voices often command self-destruction for unintelligible reasons. Psychosis is much harder to mask than depression, and is arguably even more tragic. The worldwide incidence of schizophrenia is 1% and often strikes otherwise healthy, high-performing individuals, whose lives, though manageable with medication, never fulfill their original promise.

They’re impulsive. Often related to drugs and alcohol, some people become maudlin and impulsively attempt to end their own lives. Once sobered and calmed, these people usually feel emphatically ashamed. The remorse is often genuine, but whether or not they’ll ever attempt suicide again is unpredictable. They may try it again the very next time they become drunk or high, or never again in their lifetime. Hospital admission is therefore not usually indicated. Substance abuse and the underlying reasons for it are generally a greater concern in these people and should be addressed as aggressively as possible.

They’re crying out for help, and don’t know how else to get it. These people don’t usually want to die but do want to alert those around them that something is seriously wrong. They often don’t believe they will die, frequently choosing methods they don’t think can kill them in order to strike out at someone who’s hurt them, but they are sometimes tragically misinformed. 

They have a philosophical desire to die. The decision to commit suicide for some is based on a reasoned decision, often motivated by the presence of a painful terminal illness from which little to no hope of reprieve exists. These people aren’t depressed, psychotic, maudlin, or crying out for help. They’re trying to take control of their destiny and alleviate their own suffering, which usually can only be done in death. They often look at their choice to commit suicide as a way to shorten a dying that will happen regardless. 

– Psychology today