Manic symptoms can occur in association with known organic disorders, but in such cases should be diagnosed as a mood disorder due to a general medical condition (ie, “secondary mania”) rather than as bipolar disorder. There appear to be no clinical characteristics that might distinguish the two diagnoses, and it is probable that future research will result in the shifting of many manic diagnoses from a primary to a secondary category. The list of known causal agents is long and includes drugs (eg, corticosteroids, levodopa, stimulants), metabolic disturbances (such as those associated with hemodialysis), infections, neoplastic diseases, and epilepsy (particularly partial complex seizures).
In manic patients presenting with prominent delusions and hallucinations, the differential diagnosis is likely to include schizophrenia, paranoid type. Both syndromes can present with identical clinical symptoms, which means that the diagnosis can be based only on the clinical course or on secondary features such as the presence of a family history of mood disorder, the level of premorbid adjustment, a history of manic symptoms, or a prior response to treatment. The diagnosis of schizoaffective disorder is available for cases in which the clinician is unable to choose between manic episode and schizophrenia. Unfortunately, there is at present no agreement on how this category should be defined or on its etiological or prognostic relationship to schizophrenia or mood disorder.