The results of a study by Harvard researchers indicate that the expression of genes encoding mitochondrial proteins and proteins responsible for regulating oxidative phosphorylation and ATP-dependent proteasome degradation are reduced in the brain of patients with bipolar affective disorder (BPAD). These findings suggest that the symptoms of BPAD may result from reduced energy expenditure and, consequently, from an inadequate cellular response to stress.

A post-mortem study of brain tissue of the hippocampal region from 27 individuals who died as a result of cardiovascular disease, organ failure, infection or cancer. One person committed suicide. Nine people had BPAD, eight had schizophrenia and 10 were controls.