A psychiatric disorder severe enough to keep people from work might also bring them greater risks of suicide, cardiovascular disease and some cancers, a new study suggests.
As many as one out of every two people in industrialized countries will suffer from a mental disorder at some point in their life.
“Our hypothesis is that people who take a sick leave for psychiatric reasons have the most severe mental health symptoms,” lead researcher Dr. Maria Melchior of Paul-Brousse Hospital in Villejuif, France, told Reuters Health in an e-mail.
From a database of 19,962 French workers, Melchior and her colleagues analyzed records of work absences for sickness—both psychiatric and nonpsychiatric—from 1990 to 1992. Then they linked these with mortality data between 1993 and 2008.
During the initial three-year window, 1,294 (seven percent) of the workers had at least one spell of sickness absence longer than seven days due to a mental health condition. A total of 1,144 workers died over the following 16 years, report the researchers in the September issue of the American Journal of Epidemiology.
After adjusting for known risk factors such as age and other sickness absences, those missing work with psychiatric disorders had significantly higher risks of death compared to workers who took no sick absences: six times more suicide, almost twice the cardiovascular disease and more than one and a half times as many smoking-related cancers.
“We did not expect such high associations,” noted Melchior.
The team points to several potential explanations, including the unhealthy behaviors that tend to come with mental illnesses, such as smoking and a poor diet. Social isolation and physical manifestations of stress could also contribute: Depression and other psychiatric disorders may affect the heart rate, for example, and heighten inflammatory immune responses.
Dr. Arnstein Mykletun of the Norwegian Institute of Public Health in Oslo, Norway, who was not involved in the study, pointed out, however, that mortality risks rose nearly the same amount for sickness absences due to non-psychiatric disorders as it did for psychiatric disorders.
The overall mortality rate was 1.7 times higher for sufferers of severe mental health conditions compared to those not taking sick leave, while nonpsychiatric reasons for taking extended time off from work still led to a 1.3-fold increased risk of death.
These results might indicate that it is sickness-absence in general that increases the risk of mortality, Mykletun told Reuters Health in an e-mail.
The data could signal, in other words, that serious mental illness is just as debilitating as physical illness, with similar long-term effects on overall survival.
The researchers acknowledge limitations to their study, including the likelihood that psychiatric disorders may have been underreported because of stigma and other health conditions frequently associated with such conditions.
But they also note the value that could come with identifying at-risk individuals and targeting them for interventions.
“It may be useful to offer special follow-up, aiming to reduce excessive tobacco and alcohol use as well as suicide risk among working individuals who have psychiatric disorders,” suggested Melchior.
SOURCE: American Journal of Epidemiology, online August 23, 2010.
