It has been found in a new study that cancer is the most frequent form of death among patients with with schizophrenia.
Published in CANCER, a peer-reviewed journal of the American Cancer Society, the study shows that people with schizophrenia die from cancer four times as often as people in the general population.
The findings indicate that there is a need for extra efforts to improve cancer prevention and early detection in patients with schizophrenia.
While schizophrenia is associated with an increased incidence of premature death due to high rate of suicide among individuals with the disease, this alone does not account for the shortened life expectancy seen in the patients.
There are some previous studies that suggest that cancer may play a role, even though other data show that cancer rates are actually lower among individuals with schizophrenia compared with the general population.
Prof. Frederic Limosin of the University of Reims, Robert Debre Hospital, in Reims, France and colleagues set out to more precisely determine the prevalence of cancer in patients with schizophrenia.
For that purpose, the researchers prospectively studied 3,470 patients with schizophrenia, and tracked cancer incidence beginning in 1993. They also sought to identify characteristics that might help predict which schizophrenic patients are likely to develop cancer.
The research team observed that about 14 per cent of the patients died during the eleven years of the study, a death rate was nearly four-fold higher than in the general population.
According to them, 74 patients died of cancer, making it the second most frequent cause of death behind suicide.
In men with schizophrenia, the risk of death due to lung cancer was significantly higher than that in the general population, but the risk of overall cancer death was not significantly higher.
In women, the risk of overall mortality was significantly higher than among the general population.
In female schizophrenic patients, the risk of death due to breast cancer was significantly higher than in the general population.
The researchers say that possible causes of these findings may include a delay in diagnosis due to patients paying less attention to symptoms, the difficulty for schizophrenic patients to benefit from optimum treatment, and less compliance to treatment.
Prof. Limosin stresses the need for more studies to further examine cancer rates in individuals with schizophrenia, and to define the characteristics of tumours that arise in these patients.