TY - JOUR
T1 - IQ and mental disorder in young men
AU - Mortensen, Erik Lykke
AU - Sørensen, Holger Jelling
AU - Jensen, Hans Henrik
AU - Reinisch, June Machover
AU - Mednick, Sarnoff A
N1 - Keywords: Adult; Age Factors; Analysis of Variance; Comorbidity; Denmark; Hospitalization; Humans; Intelligence; Intelligence Tests; Male; Mental Disorders; Prospective Studies; Schizophrenic Psychology; Social Class; Substance-Related Disorders
PY - 2005
Y1 - 2005
N2 - BACKGROUND: Most research investigating the relationship between IQ and risk of mental disorder has focused on schizophrenia. AIMS: To illuminate the relationship between IQ test scores in early adulthood and various mental disorders. METHOD: For 3289 men from the Copenhagen Perinatal Cohort, military IQ test scores and information on psychiatric hospitalisation were available. We identified 350 men in the Danish Psychiatric Central Register, and compared the mean IQ test scores of nine diagnostic categories with the mean scores of 2939 unregistered cohort controls. RESULTS: Schizophrenia and related disorders, other psychotic disorders, adjustment, personality, alcohol and substance-use-related disorders were significantly associated with low IQ scores, but this association remained significant for the four non-psychotic disorders only when adjusting for comorbid diagnoses. For most diagnostic categories, test scores were positively associated with the length of the interval between testing and first admission. ICD mood disorders as well as neuroses and related disorders were not significantly associated with low IQ scores. CONCLUSIONS: Low IQ may be a consequence of mental disease or a causal factor in psychotic and non-psychotic disorders.
AB - BACKGROUND: Most research investigating the relationship between IQ and risk of mental disorder has focused on schizophrenia. AIMS: To illuminate the relationship between IQ test scores in early adulthood and various mental disorders. METHOD: For 3289 men from the Copenhagen Perinatal Cohort, military IQ test scores and information on psychiatric hospitalisation were available. We identified 350 men in the Danish Psychiatric Central Register, and compared the mean IQ test scores of nine diagnostic categories with the mean scores of 2939 unregistered cohort controls. RESULTS: Schizophrenia and related disorders, other psychotic disorders, adjustment, personality, alcohol and substance-use-related disorders were significantly associated with low IQ scores, but this association remained significant for the four non-psychotic disorders only when adjusting for comorbid diagnoses. For most diagnostic categories, test scores were positively associated with the length of the interval between testing and first admission. ICD mood disorders as well as neuroses and related disorders were not significantly associated with low IQ scores. CONCLUSIONS: Low IQ may be a consequence of mental disease or a causal factor in psychotic and non-psychotic disorders.
U2 - 10.1192/bjp.187.5.407
DO - 10.1192/bjp.187.5.407
M3 - Journal article
C2 - 16260814
SN - 0007-1250
VL - 187
SP - 407
EP - 415
JO - British Journal of Psychiatry
JF - British Journal of Psychiatry
ER -