Abstract: Suicide is a puzzling social phenomenon. In this paper, the adaptation theory of suicide by de Catanzaro (1991) based on evolutionary psychology is reviewed comprehensively. The adaptation theory of suicide proposes that, suicide is most likely to occur when the ability to achieve inclusive fitness for an individual reduces sharply. Three hypotheses are induced based on this theory. First, people with high IQs are more likely to commit suicide. Second, suicidal behavior, to some extent, is heritable. Third, evolutionary and proximate cues suggesting reduced ability to promote inclusive fitness may be related to suicide ideation and behavior. Large number of empirical studies give support for these hypotheses, thus provide preliminary support for the adaptation theory of suicide. Researchers may explore further following the potential directions in this field. Researchers in computer sciences can test the adaption theory of suicide directly using simulation processes, while field workers can provide special data to test the theory. Psychologists should also address the potential link between cues connoting inclusive fitness changes and psychology of suicide. Sex differences should be included in these examinations. It should be taken into account that which type of suicide can be interpreted by the adaptation theory of suicide.

Key words: suicide, suicidal ideation, adaptation, intelligence threshold hypothesis, behavioral genetics, evolutionary psychology