Impulsivity and brain volume in patients with bipolar disorder type I and bipolar disorder type II

Abstract

IntroductionImpulsivity is a key feature of both bipolar disorder (BD) type I (BDI) and type II (BDII).ObjectiveStructural neuroimaging studies help clarifying brain mechanisms underpinning the regulation of impulsivity in BDI and BDII.AimsTo address the question whether grey matter (GM) alterations relate differently with impulsivity in BDI and BDII.MethodsWe assessed 54 euthymic outpatients, diagnosed with BDI (n = 28) or BDII (n = 26) according to DSM-IV-TR criteria. They underwent a 3 T magnetic resonance imaging (MRI) investigation. GM brain volumes were analyzed on a voxel-by-voxel basis using Statistical Parametric Mapping 8. The Barratt Impulsiveness Scale (BIS), version 11A, was used to assess trait impulsivity.ResultsBDI and BDII patients present an inverse relationship between impulsivity and GM volume in two cerebral areas: the right cerebellum (right crus I) and the interface between the left angular gyrus and the left inferior parietal cortex (Brodmann Area 39, 7, 40). More specifically, a negative relationship for BPI and a positive relationship for BPII were found in both areas.ConclusionsResults suggest that the different diagnosis between BDI and BDII could have a significant effect on GM changes according to impulsivity severity and point up the importance of considering the BP subtype distinction in neuroimaging studies on this topic.Disclosure of interestThe authors have not supplied their declaration of competing interest.