TY - JOUR
T1 - A longitudinal cohort study of intelligence and later hospitalisation with mental disorder
AU - Mikkelsen, Stine Schou
AU - Flensborg-Madsen, Trine
AU - Eliasen, Marie
AU - Mortensen, Erik Lykke
N1 - Copyright © 2014 Elsevier Inc. All rights reserved.
PY - 2014/5
Y1 - 2014/5
N2 - Objective Few studies on the associations between pre-morbid IQ and mental disorders are based on comprehensive assessment of intelligence in both women and men and include a wide range of confounding variables. Thus, the objective of the present study was to examine the association between pre-morbid IQ and hospitalisation with any mental disorder, including possible gender differences in the association. Methods The study population was born in 1959-61 and premorbid IQ was assessed with the WAIS between 1982 and 1994. Information on mental disorders was obtained from Danish hospital registers with a mean follow-up interval of 21.1 years. A total of 1106 participants were analysed. Results Those with a mental disorder had a significantly lower mean pre-morbid IQ score than those without. For women, the adjusted IQ difference was 8.5 points, and for men it was 5.1 points. A decrease of one standard deviation in pre-morbid IQ was associated with 83% greater risk of developing a mental disorder among women (HR = 1.83, 95% CI: 1.41-2.36), and 36% among men (HR = 1.36, 95% CI: 1.07-1.73) the interaction between gender and IQ was not statistically significant. Associations did not differ noteworthy between verbal and non-verbal IQ. Conclusions Pre-morbid IQ was found to be significantly associated with the development of mental disorder.
AB - Objective Few studies on the associations between pre-morbid IQ and mental disorders are based on comprehensive assessment of intelligence in both women and men and include a wide range of confounding variables. Thus, the objective of the present study was to examine the association between pre-morbid IQ and hospitalisation with any mental disorder, including possible gender differences in the association. Methods The study population was born in 1959-61 and premorbid IQ was assessed with the WAIS between 1982 and 1994. Information on mental disorders was obtained from Danish hospital registers with a mean follow-up interval of 21.1 years. A total of 1106 participants were analysed. Results Those with a mental disorder had a significantly lower mean pre-morbid IQ score than those without. For women, the adjusted IQ difference was 8.5 points, and for men it was 5.1 points. A decrease of one standard deviation in pre-morbid IQ was associated with 83% greater risk of developing a mental disorder among women (HR = 1.83, 95% CI: 1.41-2.36), and 36% among men (HR = 1.36, 95% CI: 1.07-1.73) the interaction between gender and IQ was not statistically significant. Associations did not differ noteworthy between verbal and non-verbal IQ. Conclusions Pre-morbid IQ was found to be significantly associated with the development of mental disorder.
U2 - 10.1016/j.comppsych.2014.01.004
DO - 10.1016/j.comppsych.2014.01.004
M3 - Journal article
C2 - 24559725
SN - 0010-440X
VL - 55
SP - 912
EP - 919
JO - Comprehensive Psychiatry
JF - Comprehensive Psychiatry
IS - 4
ER -
