Diagnosis cannot be confirmed with a brain scan or a blood test; however, there are several recommended tests that are useful in diagnosing this condition. These include:

• A detailed physical examination
• A detailed inspection of the history and onset of the patient's symptoms, and the duration of depressive and manic episodes. The inability to sleep is a complication common to both the manic and depressive phases. During manic phases, the person may feel too "wired-up" or excited to sleep, while during depressive phases they may feel too low and sad to sleep.
• A brain scan and routine blood tests are also recommended. These tests may help detect brain conditions such as a brain tumor or stroke that may also cause symptoms of altered mental health. Blood is also tested to check levels of hormones such as thyroid hormone.
• Once other medical conditions are ruled out, a detailed mental health evaluation is performed, usually by a trained mental health professional or a psychiatrist. The patient's family history of bipolar disorder or other mental illnesses such as schizophrenia or depression is evaluated as well as the patient's symptoms including their duration, triggers of onset and severity. History may be obtained from the individual concerned as well as from their family, close relatives or spouse.

Presentation of bipolar disorder

In most cases, people with bipolar disorder visit the doctor while suffering from a depressive phase and having suicidal thoughts. However, some patients may present during a manic phase, particularly if they are also experiencing psychosis. Psychosis mayinvolve delusional thinking and hallucinations. People with unipolar disorder or depression do not suffer from mania and it is the presence of mania that specifically indicates bipolar disorder.