Subcortical morphometry and psychomotor function in euthymic bipolar disorder with a history of psychosis

Psychomotor disturbances are prominent in bipolar disorder patients with a history of psychosis, but their neural correlates remain largely unexplored. We hypothesized that these psychomotor disturbances are associated with morphometric changes in functionally specific regions of the basal ganglia and thalamus. To test if psychomotor performance is associated with changes in volume and shape in these brain regions, we investigated 20 euthymic bipolar disorder patients with a history of psychosis and 20 healthy controls with structural magnetic resonance imaging and vertex-based morphometry. Within the patient group, the local shape of the basal ganglia was significantly associated with longer duration of illness, increased number of manic episodes, and treatment with antipsychotics. There were neither any statistically significant associations between psychomotor performance and morphometric measures in the patient group, nor any significant morphometric differences between patients and controls. We conclude that euthymic subjects with bipolar disorder and a previous history of psychosis show shape changes in regions of the basal ganglia associated to clinical variables that may predict psychomotor disturbances in bipolar disorder.