Repetitive Negative Thinking and Sleep Quality in Depression and Anxiety Before and After Psychotherapy

Major depressive disorder (MDD) and social anxiety disorder (SAD) are among the most prevalent disorders that significantly impair the lives of affected individuals. Cognitive behavioral therapy (CBT) is the first-line psychotherapy for MDD and SAD; however, treatment response is varied, and few studies have evaluated CBT against a psychological placebo in MDD and SAD. Moreover, accumulating data indicate repetitive negative thinking (RNT) and problematic sleep play an important role in depression and anxiety, yet the impact CBT has on RNT and problematic sleep is unclear. In the current study, patients with MDD (n=58) or SAD (n=60) were randomly assigned to CBT or supportive therapy (ST). Results revealed comparable effectiveness between CBT and ST in improving depression symptom severity in MDD patients. CBT also did not significantly improve social anxiety symptom severity more than ST in SAD patients. Across MDD and SAD patients, CBT did not improve RNT to a greater extent than ST. For sleep quality, CBT was more effective than ST for MDD patients but less effective for SAD patients. Exploratory analyses also showed that higher baseline depression symptom severity significantly predicted more change in depression symptoms after CBT but not ST. Higher baseline rumination marginally predicted more improvement in depression symptoms regardless of treatment arm. Study findings aid in advancing the understanding of treatment mechanisms towards improving treatment outcome.