Study title

United Kingdom

Individual

This was a two-armed parallel-group, randomised controlled feasibility trial comparing a digital app based on ACT (intervention group) to usual care (waitlist control group). Randomisation followed a 2:1 ratio stratified by, disease duration, and baseline levels of psychological distress, using fixed block sizes to maintain an equal allocation ratio throughout recruitment. A randomisation list was generated using Sealed Envelop the online service. This was administered by AB to maintain allocation concealment at the point of randomisation. Given the nature of the study it was not possible to blind participants or researchers to group allocation. All participants were asked to complete online questionnaires at baseline and at 4 weeks post-randomisation when those in the control group were expected to have completed the intervention. Participants were included if they were over 18 years of age, self-reported a diagnosis of Parkinson's, lived in the UK, had access to computer/tablet/smartphone and the internet, were able to read and communicate in English, were stable on anti-depressants or anxiolytics if taken- stable dose for a minimum of 1 month and had mild-to-moderate levels of distress determined by a score between 3-8 on the PHQ-4. Participants with severe cognitive impairment as determined by a score of 20 or above on the 6-item Cognitive Impairment Test (Katzman et al., 1983) or psychiatric conditions (e.g., psychosis, drug/ alcohol addiction) that can potentially risk failure in the treatment or limit participation in the course, were excluded.We recruited participants through the Parkinson’s UK research support network via newsletters, social media, and local groups. Interested PwP were then contacted a member of the research team who answered any questions and screened potential participants over the phone. Those who were not eligible were provided with additional information and resources where appropriate. Eligible participants were emailed the participant information sheet and links to complete the consent form and baseline questionnaire.