Conference Coverage

Comorbidities provide possible path to schizophrenia subtypes



NEW YORK – Psychiatric disorders comorbid with schizophrenia often pose a diagnostic challenge, but they can be the key for improving outcomes when they are addressed along with the core schizophrenia symptoms, according to a workshop on treatment-refractory disease at the American Psychiatric Association annual meeting.

Looking for comorbidities such as depression, panic disorder, and obsessive-compulsive disorder (OCD) is important, because treatment directed at those conditions “can have a significant effect on the psychosis as well,” reported Jeffrey P. Kahn, MD, clinical associate professor of psychiatry, Cornell University, New York.

Dr. Jeffrey P.  Kahn, clinical associate professor of psychiatry, Cornell University, New York Ted Bosworth/MDedge News

Dr. Jeffrey P. Kahn

In the workshop on managing the psychiatric diagnoses that co-occur with schizophrenia, Dr. Kahn focused on panic disorder, which, like many of the other common comorbidities, often precedes the onset of schizophrenia, sometimes by years. In a separate talk on managing comorbid OCD, many of the same themes emerged.

“Schizophrenia is a syndrome. It is a collection of symptoms, not a disease,” explained Michael Y. Hwang, MD, an attending physician at Veterans Affairs Hudson Valley Healthcare System, Montrose, N.Y. He believes that comorbid OCD, like comorbid panic disorder, might identify a subtype of schizophrenia that requires distinct therapeutic strategies.

The principle that schizophrenia represents a group of distinct illnesses with similar presentations is several decades old. Both Dr. Kahn and Dr. Hwang, who have published on this topic, acknowledged that efforts so far to identify those distinct diseases have failed. However, they suggested that the presence of comorbidities probably establishes clinically relevant subtypes.

Among psychiatric comorbidities, major depression is the most common, identified in more than half of patients with schizophrenia in some studies, according to Dr. Hwang. He reported that diagnostic criteria for OCD is met by about 12%, while Dr. Kahn estimated the prevalence of panic disorder in individuals with schizophrenia at about 20%.

In an individual with active positive symptoms of schizophrenia, isolating comorbid OCD or panic disorder often is a challenge. In older textbooks and guidelines on schizophrenia, comorbidities were not even discussed, Dr. Hwang said. Although the DSM-5 now acknowledges elevated rates of OCD and panic disorder in individuals with schizophrenia, Dr. Hwang and Dr. Kahn each indicated that the comorbidities still are not receiving adequate attention from clinicians.

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