Evidence-Based Reviews

Unipolar vs bipolar depression: A clinician’s perspective

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Rapidity of onset. Bipolar depressive episodes develop more rapidly than unipolar episodes. It is common for a patient with a bipolar spectrum disorder to transition from normal to very depressed virtually overnight, whereas in our clinical experience, unipolar episodes progress more slowly, often over several months.

Deliberate self-harm. Adolescents and young adults with a bipolar spectrum disorder frequently engage in self-injurious behavior, usually cutting with a knife, razor, or even sharp fingernails.25 Although these patients may also have thoughts of suicide and make suicide attempts, the individual usually perceives cutting as a means of gaining relief from tension and distress. These behaviors are often associated with a diagnosis of a personality disorder; in our opinion, however, they are hallmarks of a bipolar spectrum disorder.

ADHD. Bipolar disorder frequently co-occurs with attention-deficit/hyperactivity disorder (ADHD).26,27 Adults with bipolar disorder often have ADHD symptoms, which can complicate their treatment and cause functional impairment even after their mood disorder has been stabilized.28

Substance use disorders. Excessive use of alcohol and drugs is common among people with a wide range of psychiatric disorders, but patients with bipolar disorder have an unusually high rate of co-occurring substance use disorders—40% to 50%.29,30

Appetite and weight differences. Patients with unipolar depression usually experience loss of appetite and weight loss, whereas in our clinical experience, patients with bipolar depression often overeat, crave carbohydrates, and gain weight.

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