Attempted suicide is known to be an important risk factor of committed suicide. Past studies of the relationship of attempted suicide with mental disorders have shown that it is most closely related to depression. The objective of the present study was to clarify characteristics of depression and measures to prevent committed suicide by comparing depression with other mental disorders. The patients with depression were significantly more often aged, males, married, and used methods other than poisoning by solids or liquids compared with patients with other mental disorders. Particularly, the major risk factors of attempted suicide (i.e. a younger age and the female gender), did not apply to our depressed patients. These results suggest that approaches such as intensive psychiatric treatment may lead to the prevention of committed suicide in older male patients with depression who have attempted suicide.