Abstract
Perfectionism may be a clinically relevant problem on its own or as part of the etiology and maintenance of psychiatric disorders, e.g., anxiety disorders, depression, and eating disorders. Cognitive behavior therapy has been shown to be a promising treatment for managing perfectionism and its associated problems, including when being administered via the Internet, i.e., Internet-based cognitive behavioral therapy (ICBT). In the current study, seventy-eight self-referred participants underwent ICBT after an initial eight-week wait-list period, i.e., second wave of treatment. These were randomized to receive regular support from a therapist (ICBT-support) or ICBT with support on request (ICBT-request), in an eight-week treatment of perfectionism. Assessments of perfectionism were made at pre-, mid-, and post-treatment, as well as six-month follow-up, using the Frost Multidimensional Perfectionism Scale, subscale Concern over Mistakes. Mixed effects models revealed large symptom reductions for both conditions; Concern over Mistakes, Cohen's d = 1.40, 95% Confidence Interval (CI) [0.85, 1.95] for ICBT-support, and d = 1.00, 95% CI [0.51, 1.47] for ICBT-request. The effects were maintained at six-month follow-up and there were no differences between the conditions in terms of the results, opened modules, or completed exercises. A total of 28 out of 70 participants (42.4%; ICBT-support, 37.8%; ICBT-request) were classified as improved at post-treatment. Both types of ICBT may thus be beneficial in treating perfectionism, suggesting that just having the opportunity to ask for support from a therapist, when regular support is not provided, could be sufficient for many participants undergoing ICBT. However, the study was underpowered to detect differences between the conditions. The lack of a cutoff also makes it difficult to differentiate a dysfunctional from a functional population in terms of perfectionism. In addition, the study design could have affected the participants' motivational level from start, given their initial eight-week wait-list period. Recommendations for future studies include recruiting a larger sample size, a clearer cutoff for perfectionism, and the use of a non-inferiority test with a predetermined margin of change.