Long-Term Outcomes From a Randomized Controlled Trial of Acceptance and Commitment Therapy (ACT) Compared to Standard Medical Care for Improving Quality of Life in Muscle Disorders.

Introduction/aims: A previous randomized controlled trial showed that guided self-help acceptance and commitment therapy plus standard medical care (ACT+SMC) was superior to standard medical care alone (SMC) for improving quality of life (QoL) and mood at 9-weeks post randomization in a sample of people with muscle disorders (MD). This follow-up study evaluated whether these effects were maintained in the longer term alongside individual patterns of response.

Methods: The original study was a two-arm parallel group randomized controlled trial, which compared ACT+SMC to SMC. The primary outcome of QoL was assessed with the Individualized Neuromuscular Quality of Life Questionnaire. We recruited people with different MDs from UK National Health Service clinics and patient registries. In this follow-up study, we re-administered all outcome measures to participants at 6 months post randomization.

Results: Questionnaires were completed by 109 participants (70.3% of the original sample). At six months, the adjusted group difference in QoL continued to favor ACT+SMC, which was significant with moderate effect size. Improvements in secondary outcomes of mood and aspects of psychological flexibility also favored ACT+SMC. Reliable improvement was evident in 33.9% of the ACT+SMC group and 5.7% of the SMC group. Reliable deterioration was uncommon following ACT+SMC (1.8% of participants.) DISCUSSION: The beneficial impacts of guided self-help ACT for QoL and mood were maintained in the longer-term. A third of participants showed response to this brief intervention, and negative individual outcomes were very rare. As is common in psychological interventions, there was a considerable group of non-responders.