Is sleep disturbance linked to short- and long-term outcomes following treatments for recurrent depression?

Background: Pre-treatment sleep disturbance has been shown to predict antidepressant treatment outcomes. How changes in sleep disturbance during acute treatment affect longitudinal outcomes, or whether continuation-phase treatment further improves sleep disturbance, is unclear. Methods: We assessed sleep disturbance repeatedly in: a) 523 adults with recurrent MDD who consented to 12-14 weeks of acute-phase cognitive therapy (A-CT) and b) 241 A-CT responders at elevated risk for depression relapse/recurrence who were randomized to 8 months of continuation-phase treatment (C-CT vs. fluoxetine vs. matched pill placebo) and followed protocol-treatment-free for 24 months. Trajectories of change in sleep and depression during and after A-CT were evaluated with multilevel models; individual intercepts and slopes were retained and input into Cox regression models to predict remission, recovery, relapse, and recurrence of MDD. Results: Sleep disturbance improved over the course of A-CT, but most patients continued to report clinically significant sleep complaints. Response and remission were more likely in patients with less overall sleep disturbance and those with greater reduction in sleep disturbance during A-CT; these patients also achieved post-ACT remission and recovery sooner. Sleep improvements endured throughout follow-up but were not enhanced by continuation-phase treatment. Sleep disturbance did not predict relapse or recurrence consistently. Limitations: Objective sleep disturbance was not assessed. Analyses were not specifically powered to use sleep changes to predict outcomes. Conclusions: Improvements in sleep disturbance during A-CT are linked to shorter times to remission and recovery, supporting consideration of monitoring and targeting sleep disturbance in adults with depression.