The effect of premorbid intelligence on neurocognitive and psychosocial functioning in bipolar disorder

Abstract

Background: The aim of this study was to assess if premorbid IQ moderates the association between measuresof clinical severity and neurocognitive or psychosocial functioning in euthymic patients with bipolar disorder.Methods: One hundred and nineteen outpatients and forty healthy controls were included. The length ofillness, number of previous hypo/manic and depressive episodes, episode density, and history of psychosisassessed clinical severity. Performances in verbal memory, attention, and executive functions, as well as level ofpsychosocial functioning were used as outcomes.Results: The negative relationship between number of hypo/manic episodes and performance in executivefunctions decreased as a function of higher values of premorbid IQ. No other influences of premorbid IQ werefound in the association between clinical severity measures and neurocognitive and psychosocial functioning.Conclusions: Premorbid IQ might moderate the relationship between the number of hypo/manic episodes andexecutive functioning in bipolar disorder. Possible interpretations of this finding are discussed.