Increased rates of white matter hyperintensities in late-onset bipolar disorder

• Published in: Bipolar disorders Vol. 10; no. 7; pp. 765 - 775
• Main Authors: Tamashiro, Jaqueline Hatsuko, Zung, Stevin, Zanetti, Marcus Vinicius, De Castro, Cláudio Campi, Vallada, Homero, Busatto, Geraldo F, De Toledo Ferraz Alves, Tânia Correa
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.11.2008
• Subjects: Age of Onset; Aged; Analysis of Variance; bipolar disorder; Bipolar Disorder - classification; Bipolar Disorder - pathology; Brain - pathology; Disease Progression; Female; Humans; late-onset mood disorders; magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Medicin och hälsovetenskap; Nerve Fibers, Myelinated - pathology; vascular risk factors; white matter hyperintensities
• ISSN: 1398-5647; 1399-5618; 1399-5618
• DOI: 10.1111/j.1399-5618.2008.00621.x

Objectives:  Magnetic resonance imaging (MRI) studies have reported an increased frequency of white matter hyperintensities (WMH) in association with late‐onset (LO) depression, and this has supported the notion that vascular‐related mechanisms may be implicated in the pathophysiology of LO mood disorders. Recent clinical studies have also suggested a link between LO bipolar disorder (LO‐BD) and cerebrovascular risk factors, but this has been little investigated with neuroimaging techniques. In order to ascertain whether there could be a specific association between WMH and LO‐BD, we directly compared WMH rates between LO‐BD subjects (illness onset ≥ 60 years), early‐onset BD subjects (EO‐BD, illness onset <60 years), and elderly healthy volunteers. Methods:  T2‐weighted MRI data were acquired in LO‐BD subjects (n = 10, age = 73.60 ± 4.09), EO‐BD patients (n = 49, age = 67.78 ± 4.44), and healthy subjects (n = 24, age = 69.00 ± 7.22). WMH rates were assessed using the Scheltens scale. Results:  There was a greater prevalence of WMH in LO‐BD patients relative to the two other groups in the deep parietal region (p = 0.018) and basal ganglia (p < 0.045). When between‐group comparisons of mean WMH scores were conducted taking account of age differences (ANCOVA), there were more severe scores in LO‐BD patients relative to the two other groups in deep frontal and parietal regions, as well as in the putamen (p < 0.05). Conclusions:  Our results provide empirical support to the proposed link between vascular risk factors and LO‐BD. If extended in future studies with larger samples, these findings may help to clarify the pathophysiological distinctions between bipolar disorder emerging at early and late stages of life.