The key to a successful treatment of a bipolar disorder is the right diagnosis. Diagnosis may not be so easy because its symptoms are episodic. Thus, a comprehensive history is needed. Though it is a psychological illness, an exhaustive medical history and physical exam are also needed to rule out any physical cause of the symptoms of the mood disorder.

A detailed history taking and mental status examination is essential to the diagnosis of bipolar disorder. A complete history of both the present and past symptoms must be taken. Generally, depressed patients experience psychomotor retardation and have decreased activity. They have a decreased rate and volume of speech. Some may have delusions and hallucinations. They have a pessimistic view of themselves and of the world. Majority of them have attempted suicide or contemplated about it. In contrast, manic patients are very euphoric, excited and hyperactive. They are amusing to interview and they may sometimes even appear psychotic. They can have a low frustration tolerance and become very irritable.

Their speech becomes louder, faster and difficult to interpret as they can be filled with jokes, rhymes, word salad, neologisms and irrelevancies. They have difficulty concentrating on one topic and exhibit flight of ideas. Majority of manic persons have delusions of grandeur. They often boast of extraordinary abilities, affluence or power. Manic persons can be assaultive. Their judgment is impaired.

A thorough medical history and physical exam should be taken to exclude any possible physical causes of mood swings such as injury (e.g. head injury), multi-organ diseases (e.g. lupus, AIDS, etc), metabolic abnormalities (e.g. hypothyroidism, vitamin B12 deficiency, salt imbalances, diabetes, etc.), adrenal disorders (e.g. Addisons disease, Cushings syndrome, etc.) and neurological disorders (e.g. epilepsy, brain tumors, encephalitis, multiple sclerosis, etc.). Medications taken by the patient should also be accounted for because corticosteroids and drugs used to treat Parkinsons, depression and anxiety can cause the same mood symptoms. Blood and urine tests for drugs and alcohol are also advised to rule out physiological effects of these substances.

A detailed family history should also be asked because recent studies show that bipolar disorder has a strong genetic link.