Subcortical structural volumes in recently remitted first episode mania

Abstract Background Magnetic resonance imaging (MRI) studies have yielded inconsistent findings with regard to subcortical volumetric abnormalities in patients with bipolar I disorder. Duration of illness and long term medication intake could have confounded the findings. Method Volumes of nine subcortical structures were compared between 63 patients who recently remitted from their first manic episode and 77 healthy volunteers. The volumetric segmentation was performed with the automated segmentation algorithm Freesurfer version 5.1. Results There were no significant volumetric differences between the two groups in any of the structures examined including caudate, putamen, globus pallidum, nucleus accumbens, amygdala, thalamus, cerebellum, hippocampus and lateral ventricles (q > 0.05-false discovery rate corrected). Limitations All patients were on psychotropic medications at the time of scanning, which might have confounded the results. Sample size may not be large enough to detect small volumetric changes. Conclusions Patients with bipolar I disorder do not appear to have any significant subcortical volumetric abnormalities during the early stage of the disease. Thus, early stage bipolar disorder may present an opportunity for intervention to arrest neuroprogression of the disease.