Daily activity level improvement with antidepressant medications predicts long-term clinical outcomes in outpatients with major depressive disorder

Background: Major depressive disorder (MDD) significantly impacts performance of both work- and nonwork-related routine daily activities. We have shown that work productivity is significantly impaired in employed MDD patients, but the extent of impairments in nonwork-related routine activities and its association with antidepressant treatment outcomes has not been established. Materials and methods: Activity impairment was measured using the sixth item of Work Productivity and Activity Impairment Scale in the Combining Medications to Enhance Depression Outcomes (CO-MED) trial (n=665). Published norms were used to define activity impairment levels. The relationship between activity impairment and baseline sociodemographic and clinical characteristics was evaluated along with changes in activity impairment and its relationship with other clinical outcomes such as symptom severity, function, and side effect burden. Remission status at 3 and 7 months was predicted based on week 6 activity impairment level. Results: Higher psychosocial and cognitive impairments and greater number of comorbid medical conditions were associated with greater activity impairment at baseline. Proportion of participants with severe activity impairment declined from 47.6% at baseline to 18.7% at 3 months, while mean activity impairment decreased from 57.1 at baseline to 32.8 at 3 months. During course of treatment, levels of activity impairment correlated most strongly with psychosocial function among measures of symptom severity, function, quality of life, and side effect burden. No or minimal activity impairment at week 6 was associated with two to three times higher rates of remission at 3 and 7 months as compared to moderate or severe activity impairment levels even after controlling for remission status at week 6 and select baseline variables. Conclusion: Depressed patients have high levels of nonwork-related activity impairment at baseline that improves significantly with treatment and independently predicts long-term clinical outcomes. Brief systematic assessment of activity impairment during the course of antidepressant treatment can help inform clinical decision-making.