Mental illness may raise cancer risk

Patients with mental disorders may be at increased risk for certain cancers, according to a report in the journal Psychosomatic Medicine.

Dr. Caroline P. Carney, of Indiana University School of Medicine in Indianapolis, and colleagues examined the relationship between insurance claims for mental disorders and the risk of cancer.

The study included 722,139 adults who had filed at least one medical claim from 1989 to 1993.

The team compared two groups. Patients in the mental disorder group included those with one psychiatric hospitalization, one outpatient psychiatrist visit, or two outpatient mental health claims occurring at least 6 months before a cancer claim; a comparison group included those without mental health visits who had filed claims for medical services.

The overall rate of cancer in each group was similar - about 1.2 percent. However, patients with mental disorders developed cancer at about 2 years earlier in life than comparison subjects.

Men in the mental disorder group had more than twice the risk of brain tumors and more than 50 percent higher risk of lung and other "respiratory" tumors. Similar increased risks were seen among women with existing mental disorders, the researchers report.

"The increased odds of respiratory tumors are likely (due) to increased rates of smoking among people with mental disorders and support use of smoking cessation interventions in this population," Carney's group concludes.

The increase in brain cancers could reflect the presence of mental symptoms or a "true association between the two conditions," they add. Additional research is warranted.

SOURCE: Psychosomatic Medicine, September/October issue 2004.