Acute bipolar disorder depression is associated with immune activation

Recent studies indicate that immune activation may be an important component of the pathogenesis of bipolar disorder. The study sample consists of 40 patients admitted to the hospital with a diagnosis of acute bipolar depression. Blood samples were drawn at 3 time points: at time of hospital admission, during the acute hospital stay, and at a six month follow-up. Inflammatory markers were measured including C-reactive protein (CRP), Pentraxin 3 (PTX3), and antibodies to infectious agents. The markers in the bipolar depressed patients were studied over the 3 time points and also compared to those in other groups: 60 hospitalized for acute mania; 69 with recent onset psychosis; 246 with multi-episode schizophrenia; 98 with bipolar disorder not selected for mania or depression; and 222 non-psychiatric controls. The bipolar depressed patients had elevated levels of CRP at all 3 time points. The bipolar depressed patients also had elevated levels of PTX3 at hospital admission which were reduced during the hospital stay and at follow-up. The bipolar depressed group also had elevated levels of antibodies to the nucleocapsid protein of the SARS strain of coronavirus, while elevated levels of these antibodies were not found in the other groups. Our study indicates that bipolar disorder depression is associated with immune activation, particularly during acute exacerbations. These findings may lead to the development of new methods of prevention and treatment.