This first randomized trial with CBT for misophonia showed both short- and long-term efficacy. Three months of CBT reduced misophonia symptoms compared to a waiting list. Clinical improvement was found in 56% of all completers (37% intention-to-treat) compared to 0% in the waiting list. General mental and physical dysfunction decreased and patients reported less disabilities in family and social functioning after CBT than after waiting list as well. Importantly, 12 months after the end of treatment, the considerable improvement in misophonia symptoms was sustained. On top of these measurements, group therapists rated 74% of all completers clinically improved (CGI < 3).
These results confirm the positive effect of CBT previously found in case reports and a previous open-label trial in our center (Bernstein et al., 2013; Dozier, 2015; McGuire et al., 2015; Schröder et al., 2017) and extends its findings. This RCT provides evidence for the efficacy of CBT for misophonia and can serve as a stepping stone to implement CBT in clinical practice. We have published our protocol, so more misophonia patients can benefit from this treatment.
In clinical practice and future trials, these results could be improved. Patients gradually improved in time. Since there was no plateau effect (see Figure S1), there is room for further improvement. By adding more sessions, we could possibly even reach a better outcome. This notion is supported by detailed feedback of patients, who endorsed a prolonged treatment. Future studies should investigate whether additional sessions lead to additional improvement.
As opposed to the strong symptom improvement after CBT, we did not find a meaningful effect on QoL in the primary analysis. There are several reasons; first of all, a ceiling effect is probable, given the high pretreatment score on both questionnaires. We doubt misophonia has no effect on QoL, so these two questionnaires are probably not suitable for this population. Possibly, a different questionnaire, the Manchester Short Assessment of Quality of Life (MANSA; Priebe et al., 1999), would have been more sensitive, since patients with misophonia score low on the MANSA (Jager et al., 2020). Misophonia has a clear impact on social and family functioning. The MANSA has more focus on the social domain (e.g., with several items concerning the quality of relationships with friends, family, and colleagues) than the EQ5-D or WHOQoL-BREF.
In this first RCT for misophonia, the highly controlled intervention (Van Loon et al., 2019) is a major strength. The interventions were highly comparable in all treatment groups, because the study was situated in one center. Furthermore, only a few experienced therapists were involved and monitored by regular intervision. Another strength are the assessments. Assessments were thorough with the use of blinded observer ratings, clinical interviews by both therapists and observer, diverse self-reports, multiple measures during treatment, and a measure at 1-year follow-up.
