Purpose: The Maudsley Bipolar Disorder Project set out to investigate the cognitive and brain structural and functional characteristics of Bipolar Disorder I (BDI).
Methods: Participating patients were recruited while in remission from a secondary care setting and were matched to healthy volunteers in terms of age, gender, race, and years of education. All participants underwent extensive clinical and cognitive assessment. Brain structural and functional data also were obtained by using magnetic resonance imaging (MRI).
Results: Compared with controls, patients showed subtle widespread decrements, with executive function being more markedly impaired. Patients also showed volume decrements in the ventral prefrontal cortex (VPFC) bilaterally and the dorsal PFC (DPFC) on the left, whereas the volume of the amygdala was bilaterally enlarged. Patients showed subtle abnormalities in functional MRI in their DPFC, with marked decrements in activity in both the DPFC and VPFC in tasks that rely on the functional interaction of these brain regions.
Conclusions: Our results suggest that BDI is associated with trait deficits in executive function and in the structure and function of the PFC.