For example, bipolar disorder has long been thought to be the result of an over prevalence of neurotransmitters, such as epinephrine or dopamine. However, this theory does not explain why a patient can display wildly different behaviors in the depressive and manic stages; otherwise, symptoms would be more consistent. Instead, Dr. Manji has suggested that this disorder is ultimately caused by problems with protein networks inside the cells, which prevent normal functioning. This has led to new research toward greater care for bipolar patients.