Managing rumination and worry: A pilot study of an internet intervention targeting repetitive negative thinking in Australian adults

Background: Rumination and worry, both forms of repetitive negative thinking (RNT), have been implicated in the onset, maintenance, severity, and relapse risk of depression and anxiety disorders. Despite promising initial findings for internet-delivered interventions targeting both rumination and worry simultaneously, no studies have investigated treatment effects in an adult population or when delivered in a brief, unguided format. We developed a 3-lesson unguided online treatment program targeting both rumination and worry and evaluated the adherence and effectiveness in Australian adults using an open pilot trial. Methods: Adult participants (N=26) experiencing elevated levels of RNT completed the online program over 6 weeks. Outcomes were assessed at baseline, post-treatment, and 1-month follow-up. Intention-to-treat linear mixed models were used to examine effects on RNT, anxiety, depression, and general psychological distress. Results: Of the 26 participants who started the program, 18 completed all three lessons (69.2% completion rate). Large within-subject effect sizes were found between pre-and post-treatment for RNT (Hedges' g= 2.26) and symptoms of depression (g =1.04), generalised anxiety (g = 1.82) and distress (g = 0.93). Treatment effects were maintained at 1-month follow-up. Limitations: No long-term follow-up, exclusion of severely depressed individuals. Conclusions: This is the first study to evaluate a brief, unguided internet intervention targeting both rumination and worry in adults. The results provide promising preliminary evidence for the feasibility and acceptability of the online program. Randomised controlled trials are needed to evaluate treatment efficacy compared to a control group and to investigate long-term outcomes.