Background: Although some depression trials have included quality of life (QoL) as an outcome measure, assessments were retrospective and relatively infrequent. Because QoL varies in relation to everyday experience, intensive time-sampling approaches may be useful.
Method: The experience sampling method (ESM) was used to assess effects of antidepressant treatment on the quality of life, as measured from moment to moment in daily life (mQoL), and related aspects of daily experience. Primary care patients with a DSM-III-R/DSM-IV diagnosis of major depressive disorder were randomly assigned to imipramine (N = 32) or placebo (N = 31) treatment for 6 weeks, with possible prolongation to 18 weeks. A healthy control group (N = 22) provided normative data.
Results: Treatment-related increases in frequency and severity of physical complaints, including those not reported to the general practitioner as side effects, were associated with lowered mQoL; this negative association was especially strong in treatment dropouts. Despite greater clinical improvement at week 6, imipramine patients did not report greater increases than placebo patients in mean mQoL ratings. However, imipramine treatment stabilized mQoL fluctuations and led to reductions in time spent "doing nothing." Patients' decisions to prolong treatment depended on clinical improvement, mQoL changes, and specific early side effects. At 18 weeks, remitted patients still showed deficits on ESM daily life measures relative to healthy controls, even though QoL had returned to normal on retrospective measures.
Conclusion: ESM provides new insights in the effects of antidepressant treatment on daily life experiences and should therefore be considered as a supplement to conventional instruments in clinical trials.