Two recent reviews in the American Journal of Psychiatry and the British
Journal of Psychiatry reported on progress in understanding the genetics of
psychiatric disorder. Both reviews focused on this progress as a prelude to
psychiatric diagnostics and therapeutics based on molecular biology.
Neither review recognized that the latest data in behavioral genetics
support environmental causes for abnormal development and psychopathology
as much as they support genetic causes. Moreover, these genetic data point
clearly to a type of environmental cause with central importance: the
environment that is specific or unique to each sibling in a family.