The interaction of parental history of suicidal behavior and exposure to adoptive parents' psychiatric disorders on adoptee suicide attempt hospitalizations.

OBJECTIVE: The authors examined the risk of suicide attempt or other psychiatric hospitalization among adoptees whose biological parents died from or were hospitalized for suicidal behavior (BPSB) relative to adoptees whose biological parents had a psychiatric hospitalization but never for suicide attempt (BPPH). The authors examined whether risk was moderated by having an adoptive parent who had a psychiatric hospitalization during the adoptee's childhood or adolescence.

METHOD: This retrospective cohort study used national longitudinal population-based Swedish registry data from 1973 to 2003 to identify 2,516 adoptees with BPSB and 5,875 adoptees with BPPH. Cox regression models compared the risk for suicide attempt and other psychiatric hospitalization in the two groups.

RESULTS: The interaction of BPSB with adoptive mothers' psychiatric hospitalization while the adoptee was younger than 18 years old increased the risk for an adoptee's suicide attempt. Neither BPSB nor psychiatric hospitalization among adoptive mothers alone placed adoptees at greater risk for suicide attempt hospitalizations. The interaction results were specific to adoptee suicide attempt.

CONCLUSIONS: Exposure to the hospitalization of an adoptive mother because of a psychiatric disorder amplified an adoptee's risk for suicide attempt hospitalization among those adoptees at high genetic risk of suicide or suicide attempt. These results imply that suicide attempts among those at biological risk might be prevented with the early recognition and care of parental psychiatric illness.