Testing Self-Help Interventions for Adults with Clinical Perfectionism: A Randomized Controlled Trial Comparing Online Skills Modules to a Book

Objective: The current randomized controlled trial (preregistered at https://osf.io/8k7xa) compared an online self-help intervention for perfectionism that allows users to select their own skills modules to a book control condition. Method: Participants with clinically significant perfectionism (N = 114; mean age = 33.9, 52.3% white, 58.7% women) were randomly assigned to an online training (app) or active control (self-help book) condition and assessed at baseline, weekly during a 4-week intervention period, at 1-month follow-up, and at 6-month follow-up. Results: We found a smaller decrease in perfectionistic evaluative concerns in the app condition compared to the book condition (FMPS-Evaluative; ps = .002 to .007), but no differences were observed for perfectionistic striving (FMPS-Striving), psychological distress (DASS), quality of life (QOLS), psychological flexibility (Psy-Flex), and self-compassion (SCS-SF) by 6-month follow-up (Cohen’s ds for perfectionism subscales = -0.79 to -0.42 for the app, -1.12 to -0.88 for the book). Participants in the app condition rated modules as being more helpful for meeting specific than general needs (t = -2.40, p = 0.021), suggesting they could “self-personalize” treatment by selecting modules that fit their needs at the time of use. We did not find significant moderation effects for any demographic or clinical variables. Conclusions: Both interventions showed similar effects over time and may serve as helpful low-intensity treatments for clinical perfectionism. Limitations include lack of a waitlist control condition, which precludes conclusions about efficacy of the study interventions beyond time effects.