Associations between antidepressant therapy, work ability, and sick leave for patients with common mental disorders within a two-year perspective – A longitudinal observational cohort study in Swedish primary care

BACKGROUND: An increasing number of patients are on sick leave because of common mental disorders (CMD), with or without antidepressant therapy. There is a lack of long-term follow-up studies in the primary care context, where most of the patients are treated. The importance of identifying potential factors associated with work ability for CMD patients is increasingly in focus. OBJECTIVE: To investigate the associations between using antidepressants, sick leave duration, reported work ability and psychological symptoms among patients with CMD during a two-year observation period in the primary care context. METHODS: Longitudinal observational cohort study at 28 Primary Care Centers in Region Västra Götaland, Sweden, including 182 patients with an employment and on sick leave for CMD. The following outcomes were assessed: work ability measured with WAI, depressive symptoms with MADRS-S, anxiety symptoms with BAI, fatigue symptoms with KEDS, quality of life with EQ-5D, and days of sick leave. The data were compared between the groups that used and did not use antidepressants, during the 24-months observation period. RESULTS: Work ability and health-related quality of life increased over time in both groups. A steeper decrease of depressive symptoms, anxiety symptoms as well as an increased health-related quality of life at 3, 6 and 12 months was found in the group without antidepressants, although both groups levelled off at 24 months. In both groups, a higher work ability at baseline was associated with less two-year sick leave. CONCLUSION: Our study indicates that a high work ability at baseline has a strong association with a lower total net and gross sick leave duration during the entire two-year follow-up period for patients with CMD in primary health care, irrespective of use of antidepressants. Using WAI in primary health care could therefore be helpful in predicting return to work. Use of antidepressants during the CMD episode could indicate initially a more pronounced overall symptom pattern, motivating introduction of antidepressants, rather than prolonging the sick leave period.