Association of IQ scores and school achievement with suicide in a 40-year follow-up of a Swedish cohort.
OBJECTIVE
Few studies have investigated the association of childhood IQ and school achievement with suicide. The aim of this study was to investigate the association of childhood IQ with suicide in a cohort of Swedish women and men.


METHODS
21 809 subjects born in 1948 and 1953 who completed IQ and school tests at age 13 years have been followed until 2003. Information on paternal education and in-patient care for psychosis was linked using the Swedish personal identification number.


RESULTS
There were 180 suicides amongst subjects with measured IQ. High IQ was associated with reduced suicide risk among men (OR per unit increase in age-adjusted model 0.90, 95% CI 0.83-0.99), while there was no statistical evidence of an association in women (OR 1.04, 95% CI 0.90-1.20). Among men with a history of psychosis, high IQ was associated with an increased risk of suicide.


CONCLUSIONS
Low childhood IQ at age 13 years is associated with an increased risk of suicide in men but not in women; however, amongst those with psychosis, low IQ appears to be protective.
Andersson
L
L
Department of Public Health and Community Medicine, Social Medicine, Sahlgrenska Academy at Göteborg University, Göteborg, Sweden. lena.andersson@socmed.gu.se
Allebeck
P
P
Gustafsson
J-E
JE
Gunnell
D
D
D000293:Adolescent; D003071:Cognition / Q000502:physiology; D015331:Cohort Studies; D004522:Educational Status; D005220:Fathers / Q000523:psychology / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D007361:Intelligence Tests / Q000706:statistics & numerical data*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011618:Psychotic Disorders / Q000453:epidemiology / Q000523:psychology; D017678:Sex Distribution; D012959:Socioeconomic Factors; D013405:Suicide / Q000523:psychology* / Q000706:statistics & numerical data*; D013548:Sweden / Q000453:epidemiology