Background: Compared with normal-weight patients, obese patients with bipolar I disorder (BD) suffer more manic and depressive episodes and make more suicide attempts. In the general population, obesity is associated with reduced total brain volume (TBV) and gray matter volume (GMV), but the neurobiology of obesity in BD has not been investigated. Methods: We used magnetic resonance imaging to examine TBV, GMV, white matter volume (WMV), as well as frontal, parietal, occipital, and temporal lobe volumes, in 55 healthy subjects (17 overweight/obese and 38 normal weight) and 57 patients with BD following their first manic episode (20 overweight/obese and 37 normal weight). Results: Linear regression analyses demonstrated that when other predictors of brain volume were accounted for, increased body mass index (BMI) in healthy subjects was significantly associated with decreased TBV and GMV. In contrast, increased BMI in patients with BD was significantly associated with decreased WMV and temporal lobe volume, areas of known vulnerability in early BD. Conclusions: This is the first published report to show a relationship between elevated BMI and reduced brain volumes in BD, or any psychiatric illness. Our results suggest that obesity is associated with unique neurobiological changes in BD. They further imply a possible biological mechanism underlying the association between obesity and a more severe illness course in BD.
Bibliographical noteFunding Information:
This work was supported by an unrestricted grant from AstraZeneca , Canada. The sponsor had no involvement in designing the study, collecting, analyzing, or interpreting the data; writing the report; or the decision to publish the report. These data were presented in part at the 4th Biennial Meeting of the International Society for Bipolar Disorders, São Paulo, Brazil, March 17–20, 2010.
Dr. Bond is on speaker/advisory boards for, or has received research grants from: the Canadian Institutes of Health Research (CIHR) , the UBC Institute of Mental Health/Coast Capital Depression Research Fund , the Canadian Network for Mood and Anxiety Treatments (CANMAT) , the Canadian Psychiatric Association , AstraZeneca , and Janssen-Ortho .
Dr. Honer has received consulting fees or sat on paid advisory boards for the Alberta Heritage Medical Research Foundation, In Silico, Janssen, Novartis, and AstraZeneca; received lecture fees from Partners in Psychiatry, Hotel Dieu Hospital (Kingston), Rush University, the Capital Mental Health Association (Victoria), Université de Montréal, Janssen, and AstraZeneca; and received educational grant support from Janssen , Eli Lilly and AstraZeneca .
Dr. Lam is on speaker/advisory boards for or has received research grants from AstraZeneca , Biovail , Bristol-Myers Squibb , Common Drug Review , Canadian Institutes of Health Research , Canadian Psychiatric Research Foundation , Canadian Network for Mood and Anxiety Treatments , Eli Lilly , Litebook Company, Ltd. , Lundbeck , Lundbeck Institute , Pfizer , Servier , UBC Institute of Mental Health/Coast Capital Savings , and Takeda .
Dr. Yatham is on speaker/advisory boards for or has received research grants from AstraZeneca , Bristol-Myers Squibb , CIHR , CANMAT , Eli Lilly , GlaxoSmithKline , Janssen , Lundbeck , Merck , the Michael Smith Foundation for Health Research , Pfizer , Servier , Merc , and the Stanley Foundation .
- Bipolar disorder
- body mass index
- brain volume
- first-episode mania
- magnetic resonance imaging (MRI)