How is long-term sickness absence due to different mental disorders associated with future disability pension risk? A population-based prospective cohort study in Finland.

OBJECTIVES

The rise in mental disorders in Organisation for Economic Co-operation and Development (OECD) countries warrants close consideration, as mental disorders cause long-term sickness absences (LTSA) and increase the risk of disability pensioning (DP). This study compared how different mental disorders as a basis for LTSA pose risks for a subsequent DP.

DESIGN

Population-based prospective cohort study.

SETTING AND

PARTICIPANTS

18-59-year-old Finns starting a new psychiatric LTSA in 2020. LTSA was measured through sickness allowance accumulated over 12 months. A 48-month follow-up started from the onset of LTSA. Six mental disorder types were identified.

OUTCOME MEASURES: The outcome variable was the time in months to a first paid DP spell. Using Cox proportional hazards regression stratified by sex, the DP risks of different mental disorders were examined, adjusting for comorbidity, length of LTSA and sociodemographic variables. The risks are presented as absolute risk differences and both unadjusted and covariate-adjusted HRs.

RESULTS

Compared with depression-related LTSA, psychoses (HRs 2.93 (95% CI 2.55 to 3.36) for women/2.99 (95% CI 2.67 to 3.36) for men) and other mood disorders (HRs 1.64 (95% CI 1.40 to 1.92)/1.49 (95% CI 1.25 to 1.78)) were associated with higher covariate-adjusted HRs, while anxiety disorders (HRs 0.65 (95% CI 0.59 to 0.72)/0.76 (95% CI 0.67 to 0.87)) and psychiatric sleep disorders (HRs 0.47 (95% CI 0.38 to 0.59)/0.58 (95% CI 0.44 to 0.78)) showed lower HRs. Higher age, lower education and socioeconomic status, comorbid mental disorders, chronic diseases and longer LTSA increased the risk.

CONCLUSIONS

Different mental disorders as basis for LTSA pose differing risks for permanent work disability. Among mental disorders, depression poses a relatively average risk for DP. Although anxiety and sleep disorders commonly cause LTSA, they are not associated with high DP risks. Psychotic and bipolar disorders are especially detrimental to work ability in today's work life.