People often think about suicide for a long time, but attempts often follow an acute crisis
Consequently, suicide attempts are often impulsive and in response to the immediate crisis
Deisenhammer, E.A., Ing, C.M, Strauss, R. et al. (2009). The duration of the suicidal process: how much time is left for intervention between consideration and accomplishment of a suicide attempt? Journal of Clinical Psychiatry, 70(1), 19-24.