Feasibility of acceptance and commitment therapy for repetitive negative thinking versus internet-based CBT: a pilot randomised controlled trial in Swedish primary care among patients with anxiety, depression and stress

Abstract Background Repetitive negative thinking (RNT) is a transdiagnostic process relevant to common mental health problems in primary care. RNT-ACT is a brief acceptance and commitment therapy-based protocol targeting RNT in two sessions. This pilot study assessed the feasibility of RNT-ACT compared with therapist-supported internet-based cognitive behavioural therapy (iCBT) in Swedish primary care. Methods Thirteen participants were randomised: 7 to RNT-ACT and 6 to iCBT. The primary feasibility outcomes were recruitment rate, intervention non-completion, and patient satisfaction measured with the Client Satisfaction Questionnaire (CSQ-8). Symptom and process measures were secondary outcomes. Secondary outcomes were assessed at baseline and at 1- and 3-month follow-ups. Analyses were descriptive and exploratory, based on available observations without imputation of missing data. Results Thirteen of 20 eligible individuals were enrolled (65%), corresponding to 35% of all 37 individuals screened. All participants in the RNT-ACT group completed the intervention, whereas 4 of 6 participants in the iCBT group did not complete the intervention. Mean CSQ-8 scores were 27.8 (SD 3.7; n = 5) in the RNT-ACT group and 23.0 (SD 0.0; n = 2) in the iCBT group. Conclusions The small sample size and high iCBT non-completion limit between-group comparisons. Further investigation of recruitment, treatment engagement, and patient and therapist experiences is needed before determining whether and how to proceed to a full-scale RCT. Trial registration ClinicalTrials.gov NCT05946382 registered July 14, 2023.