I think what is left out of most of today's psychotherapy paradigms regarding the causes and purposes of self-destructive or irrational thinking is an understanding of groupthink processes. Humans are the most social of all organisms and the attachment neuroscience is showing us how powerful primary attachment figures are in shaping, triggering, and reinforcing our social behavior.

Another important but ignored consideration is kin selection - the evolutionary tendency to sacrifice ourselves for the needs of our kin group in certain social contexts.