This study used health insurance claims data to examine the relationship between the length of sick leave and treatment administered to employees who received middle- to long-term accident and sickness benefits for ≥91 d due to mood disorders, anxiety, and dissociative, stress-related, somatoform and other nonpsychotic mental disorders. Employees who received psychotherapy had significantly shorter leaves of absence over one year compared to those that did not. Treatment with psychotropic drugs was significantly higher among those on leave for ≤365 d than those on leave for ≥366 d. Age, sex and hospital treatment were not significantly associated with length of sick leave. These results suggest that professional psychological treatment is associated with length of sick leave.