Q: What is catatonia? Can it be treated?

A: Catatonia is a disorder of motor functioning. It was first described in 1874. By the turn of the 20th century, an influential psychiatrist named Emil Kraepelin had linked it to schizophrenia.

As a result, it's been hard for clinicians to recognize catatonia as an illness in its own class. It probably has more in common with movement disorders, such as Parkinson's disease, than mental disorders like schizophrenia.

People with catatonia can't control movement. Some freeze or become rigid. Others cannot stop repetitive movements. Some can't speak.

People with catatonia appear to be purposely refusing to move. And they may not eat or drink. Or they may stare. They may not even respond to pain.

Catatonia has many causes. It often appears in mental disorders, but not just schizophrenia. It can also show up in depression or bipolar disorder.

General medical conditions can also cause catatonia. Examples are infections and autoimmune disorders (for example, lupus).

The 2013 psychiatric diagnostic manual reflects this updated understanding. Catatonia is listed as a syndrome that can happen with schizophrenia, a mood disorder, or a general medical disorder. If a patient has catatonia, doctors should search for an underlying medical cause.

There are two effective treatments. Patients whose movements are rigid or restricted may respond well to lorazepam (Ativan). Doctors sometimes give this in high doses.

Electroconvulsive therapy (ECT) is a second option. This is for a person who is agitated or delirious. Or for someone who doesn't respond to lorazepam.

Together, these two treatments benefit at least 80 percent of patients. Some studies suggest the success rate may be even higher.

(Michael Craig Miller, M.D., is an Assistant Professor of Psychiatry at Harvard Medical School and an associate physician at Beth Israel Deaconess Medical Center, Boston, Mass. He is a Senior Medical Editor at Harvard Health Publications.)

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