A retrospective study from the United Kingdom has found a strong correlation between severe mental illness and an increased risk for death from cardiovascular disease and stroke, but not from the most common forms of cancer. The study also attempted to assess the impact that antipsychotic medication, smoking, and poverty may play in the increased risks, but these results were conflicting.

The health histories of 46,136 people who had been diagnosed with a severe mental illness after age 18 and 300,426 people without severe mental illness were evaluated. Patients from 728 general practices were included, representing a broad range of mental illnesses: schizophrenia, schizo­­­affective disorder, bipolar disorder, delusional disorder, brief psychosis, and unipolar depressive psychosis. The most common diagnoses were schizophrenia (40.2%), bipolar affective disorder (23.3%), and delusional disorder (19.2%).

The youngest age-group (18- to 49-year-olds) with severe mental illness had an almost threefold increase in risk of death from cardiovascular disease, while the middle group (ages 50 to 75) with severe mental illness had a twofold increase in death from stroke. The hazard ratios for cardiovascular mortality in people with severe mental illness were 3.22 for people ages 18 to 49, 1.86 for those ages 50 to 75, and 1.05 for people older than 75. Hazard ratios for stroke death were 2.53 for those younger than 50, 1.89 for those ages 50 to 75, and 1.34 for those older than 75.

Lead author David P. J. Osborn, PhD, of the Royal Free and University College Medical School in London, described the national data source used in the study—General Practice Research Database—as “a valuable resource for examining specific associations between carefully defined exposures (such as a specific drug) and outcomes (such as coronary heart disease, specific cancers, or a specific adverse effect).”

The data set allowed a subanalysis on the impact of antipsychotic medication. Researchers found that the risk of dying from heart disease for patients with severe mental illness increased, particularly among the 50-to-75 age-group, when higher doses of antipsychotic medication were taken. Patients with severe mental illness who did not receive any antipsychotics as part of their treatment still had a higher risk of death from cardiovascular disease and stroke when compared with controls.

The only significant result for cancer deaths was an unadjusted hazard ratio for respiratory tumors of 1.32 for 50- to 75-year-olds, but the results were not statistically significant, explained Dr. Osborn, because they could be partly explained by smoking history and deprivation of health care.

While the sample included almost all people with severe mental illness in the UK, including those in long-term care, it is a limitation that homeless people were likely not well represented because they may not seek or have access to adequate health care. The authors suggested that risk of cardiovascular disease among homeless people with severe mental illness may be even higher.

Smoking data were not captured for all patients in the study but were extrapolated from studies of similar populations that included information on smoking history and prevalence. Another limitation was that causes of death were available for only 75.4% of both the severe mental illness and the comparison cases.

The study authors suggested that because patients with severe mental illness are at a greater risk of death from heart disease than is the general population, their treatment, including antipsychotic prescriptions, diet, and exercise, ought to be more closely monitored.

—Kathlyn Stone

Suggested Reading
Osborn DPJ, Levy G, Nazareth I, et al. Relative risk of cardiovascular and cancer mortality in people with severe mental illness from the United Kingdom’s General Practice Research Database. Arch Gen Psychiatry. 2007;64:242-249.

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