Getting an accurate bipolar diagnosis can be difficult because the symptoms of bipolar disorder are similar to other psychiatric conditions.

Bipolar disorder is more prevalent than was previously thought, but this illness, particularly bipolar disorder II, is still poorly recognized in the family-practice setting. It is estimated that only one-third of affected people are diagnosed. Of those, less than a third receive appropriate therapies. This makes bipolar disorder the most undertreated of psychiatric conditions.

Conditions Similar to Bipolar Disorder

When making a diagnosis of bipolar disorder, it is important that the physician rule out other conditions that may be causing symptoms of bipolar disorder symptoms.

Distinguishing Mania from Normal Euphoria or Joy

A major difficulty with a diagnosis of bipolar disorder is the tendency for a patient to be unable to recognize his or her own condition, particularly the manic form. The patient often denies these symptoms, which they may perceive as positive feelings. The physician should take a careful and complete history of any and all episodes of depression, mania, or both. Hypomania, the less severe variant of mania, may be particularly difficult to distinguish from normal joy or euphoria. It can often be differentiated by the following characteristics

• Hypomania persists for at least four days.
• Most patients with hypomania are easily distracted and overly talkative.
• Patients with hypomania tend to not function very well.

Distinguishing Unipolar from Bipolar Depression

People with bipolar disorder are more likely to first seek help because of a depressive episode. Indeed about 16% of people with bipolar disorder do not have a manic episode until they have experienced three or more depressive episodes. In such cases, the condition is often diagnosed as depression. An accurate diagnosis is important because bipolar disorder patients who are inappropriately medicated with antidepressants (antidepressants can initiative mania in bipolar patients) have a higher incidence of rehospitalization than other bipolar disorder patients do.

A family history of manic-depressive illness may make a physician suspicious, but a diagnosis of bipolar disorder cannot be established until a manic or hypomanic episode has occurred.

Bipolar disorder should be suspected in patients who have previously been treated for depression and who had an initial fast and good response, which was followed by failure. And, furthermore, they were then resistant to other antidepressants. Bipolar patients are also more likely to have atypical depression symptoms and to be emotionally volatile.

Attention Deficit Hyperactive Disorder (ADHD). Children or adolescents with manic-depressive illness may be inappropriately diagnosed with attention deficit hyperactivity disorder. ADHD and bipolar disorder often cause inattention and distractibility, and the two disorders may be difficult to distinguish, particularly in children. In some cases, ADHD in children or adolescents can even be a marker for an emerging bipolar disorder. The primary way to differentiate bipolar disorder from ADHD is by the presence of a manic or hypomanic episode, which occurs in patients with bipolar disorder but not with ADHD. Most children with bipolar will also respond to the drug valproate (Depakote), which doesn't typically work for ADHD in children.

Schizophrenia. Severe manic episodes that include delusions and hallucinations may be easily confused with schizophrenia. (African-American men, for instance, are more likely to be diagnosed with schizophrenia than with bipolar disorder.) The key factors that distinguish bipolar disorder from schizophrenia are the following:

• The presence of one or more manic or hypomanic episodes can often help distinguish bipolar disorder from schizophrenia.
• In schizophrenia, the emotional expression is flat, with no variability in the voice, while people with bipolar disorder are typically very expressive.

Substance Abuse. Up to 60% of bipolar disorder patients abuse alcohol and drugs at some point in the course of their illness. Both diagnosis and treatment are difficult in such cases, since substance abuse is often a method of self-treatment, and withdrawal can produce symptoms of mania or severe depression. The effects of cocaine in a heavy user can also produce abnormal mood swings that closely resemble those of bipolar disorder.

Other Causes of Mood Swings

Other conditions that can cause mood swings include the following:

• Thyroid disorders. Hypothyroidism may be common in bipolar patients, particularly women. (This condition can be identified with a blood test).
• Adrenal disorders (e.g., Addison's disease, Cushing's syndrome).
• Vitamin B12 deficiency.
• Certain neurologic disorders (e.g., Huntington's disease, epilepsy, brain tumors, encephalitis, multiple sclerosis).
• A number of medications, including corticosteroids and certain drugs used to treat anxiety, Parkinson's disease, and depression can cause mood swings.