There Is No Difference in IQ between Suicide and Non-Suicide Psychiatric Patients: A Retrospective Case-Control Study

Objective The goal of this study was to examine the association between IQ and suicide in psychiatric patients. Methods We conducted a nested case-control study using data obtained from psychiatric patients affiliated with a general hospital in Seoul, Korea. In a one-to-two ratio the psychiatric patients who died of suicide (Suicide Group; n=35) were matched to those who didn't (Non-suicide Group; n=70) by age, gender, psychiatric diagnosis and approximate time of first treatment. IQ was measured using the Korean version of the Wechsler Adult Intelligence Scale-Revised. Results There were no significant differences in any type of IQ between suicide patients and non-suicide patients. Logistic regression showed no evidence of an association between IQ and suicide. Conclusion These results do not support the existence of an association between IQ and suicide.