Mental Disorders Trigger Long-Term Sick Leave
By Rick Nauert PhDSenior News Editor
Reviewed by John M. Grohol, Psy.D. on August 1, 2012
Paradoxically, while everyone attempts to avoid the scenario, the precipitating factors that cause an individual to go on long-term leave have not been investigated in a thorough manner.
A new study by Norwegian, Australian and British researchers identifies anxiety as a more important risk factor than previously thought.
Experts say that common mental disorders such as anxiety and depression will affect 1 of 3 of us at some point in our lives.The core symptoms of mental disorders affect a person’s emotional, cognitive and social functioning, which can impact on working ability.
While prior studies have found a link between mental disorders and sick leave, researchers were uncertain as to whether mental disorder increases the risk of sick leave, or the other way around.
Specialists also know that prolonged absence from the workplace can contribute to avoidance behavior, especially in those with anxiety. This complication can make it even harder for these individuals to get fully back to work.
Because of this, researchers examined the long-term associations between common mental disorders and sick leave. The study was designed to help professional sdevelop more effective interventions aimed at preventing and reducing sick leave among individuals with common mental disorders.
Investigators examined anxiety and depression levels among 13,436 participants in the Norwegian Hordaland Health Study. They used the Hospital Anxiety and Depression Scale to assess common mental disorders at the start of the study.
Participants were then followed for up to 6 years, retrieving information on sick leave of 16 days or more from the official Norwegian registry. Information on other possible causal factors such as socioeconomic status and physical health was also obtained from the health study.
Results showed that common mental disorders increase the risk of very prolonged absence (over 90 days) and repeated episodes of sick leave.
Secondly, the risk of these outcomes is highest among those with both anxiety and depression simultaneously.
Thirdly, the results indicate that anxiety may be more important than depression.
“Surprisingly, we found that anxiety alone is a stronger risk factor for prolonged and frequent sick leave than depression alone. Further, anxiety seems to be a relatively stable risk factor for sick leave, as we found an increased risk of sickness absence up to six years after the anxiety level was assessed,” said Ann Kristin Knudsen, lead author of the study.
Researchers determined that a number of risk factors can simultaneously influence long-term sick leave. Not surprisingly, pain was found to have a considerable impact on the association between common mental disorders and sick leave: adjusting for pain (“removing” its effect in the statistical model) reduced the association.
“Adjusting for pain may have given us artificially low effect sizes, since pain, anxiety and depression are closely related and may reflect the same underlying health condition,” said Knudsen, a doctoral student at the University of Bergen.
In other words, the association between common mental disorders and sick leave may actually be stronger.
Researchers believe the study format which included a long-term follow-up period (6 years) helped to show that the effect of mental disorder on sick leave continues over time.
“Previous research has largely been based on patient data, organizational data or diagnoses of sick leave certificates, or in studies where the prevalence of mental disorder was measured during sick leave. The latter is problematic because we do not know what comes first, sick leave or mental health problems,” said Knudsen.
Since this was a prospective study, following individuals both with and without common mental disorders over time, it provides evidence that common mental disorders increases risk of sick leave and not the other way around.
On the other hand, people with common mental disorders also suffered several episodes of sick leave during the follow-up time, which may indicate that both sick leave and the mental health problems affect each other and thus result in a “vicious circle” with repeated sick leaves.
Researchers believe the study clearly shows the detrimental effects of anxiety, a factor that had largely been ignored in previous studies. As a result, earlier studies may have overestimated the effect of depression on sick leave.
Recognition of mental disorders can steer interventions to help prevent the prolongation of sick leave or further sick leave episodes.