Vicious Circle of Comorbidity Links Medical, Mental Illness


NEW YORK – Schizophrenia and bipolar disorder pose a triple health threat: The conditions themselves are associated with a higher prevalence of serious medical illness, some drugs used to treat them increase disease risk, and affected individuals are likely to have inadequate medical care, Ilise D. Lombardo, M.D., said at a conference on schizophrenia sponsored by Columbia University.

The unhealthful influence is bidirectional: The psychiatric course tends to be worse in individuals with chronic medical conditions or medical risk factors like obesity. (For example, a survey of 1,379 bipolar patients found that 44% had comorbid medical conditions and linked the presence and severity of medical problems to the severity of the psychiatric disorder.)

“Psychiatrists should monitor risk factors, coordinate care with internists, and involve families in medical issues,” said Dr. Lombardo of the university.

Serious mental illness is life-threatening: The rate of mortality from natural causes among patients with bipolar disorder and schizophrenia is double that of the population as a whole; for unipolar depression, the mortality rate is 1.5 times that of the general population. Cardiovascular disease and, to a lesser extent, endocrine disorders are mainly responsible for the higher rates.

This increased mortality is not surprising in light of the high prevalence of cardiovascular risk factors in the psychiatric population, Dr. Lombardo said.

Among patients with schizophrenia, 18% have elevated total cholesterol levels, 20% have hypertension, 75% smoke cigarettes, about 50% are overweight or obese, and 72% are sedentary.

An estimated 30%–60% of schizophrenia patients have metabolic syndrome–a constellation of abdominal obesity, lipid abnormalities, and abnormal glucose metabolism that triples the risk of dying of a myocardial infarction, Dr. Lombardo said at the meeting, which was cosponsored by the New York State Psychiatric Institute.

But although the medical needs of people with severe and persistent mental illness would appear to be greater, they “have less access and less quality medical care,” said Dr. Lombardo, who is also medical director for Pfizer Inc.

A review of 175,653 patients in Veterans Affairs medical centers in Southern California and Nevada found a highly significant association between a diagnosis of schizophrenia and fewer physician visits. Two-thirds of schizophrenia patients did not have such prevalent conditions as diabetes, hypertension, or chronic obstructive pulmonary disease listed among their medical diagnoses.

“If a patient with schizophrenia is hospitalized with chest pain, he is less likely to have aggressive cardiac care and more likely to die of a myocardial infarction,” Dr. Lombardo said.

Obesity, a risk factor for both diabetes and cardiovascular disease, is highly prevalent among patients with both schizophrenia and diabetes. In one study of 114 new-onset patients with schizophrenia, the mean body mass index at the time of diagnosis was 24.5 kg/m2–the upper limit of normal. After 1 year, mean body mass index in these patients had climbed to 27.5, within the obesity range. “Most weight gain occurred in the first 6 months,” she said.

“Is it due to the illness itself, lifestyle changes related to the psychological burden of the illness, or treatment? There is good evidence that all three are involved,” Dr. Lombardo said.

The problem is at least as pronounced in bipolar disorder: A study of 644 patients found that 60% were overweight, 20% were obese, and 5% were “extremely obese.”

Not only is being overweight associated with an increased risk of hypertension, arthritis, and diabetes, it apparently has negative psychiatric consequences as well. In one group of bipolar patients, time to relapse was significantly shorter among the 46 who were obese than among the 79 who were not. In 20 weeks, 30% of the obese patients had relapsed, compared with a negligible number of the nonobese.

In a study of individuals with schizophrenia, 26% of normal-weight patients were noncompliant with treatment, compared with 39% of overweight and 47% of obese patients, Dr. Lombardo said.

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