The effectiveness of metacognitive therapy on emotional distress tolerance and medication adherence in patients with generalized anxiety disorder: a pilot randomized controlled trial

BACKGROUND: Generalized Anxiety Disorder (GAD) is one of the most common mental disorders. Current treatments often emphasize symptom reduction while neglecting key factors such as emotional distress tolerance and medication adherence. Metacognitive Therapy (MCT) provides a distinct approach by targeting maladaptive metacognitive beliefs that sustain anxiety and worry. This study aimed to evaluate the effectiveness of MCT in improving emotional distress tolerance and medication adherence among patients with GAD, with the goal of facilitating its clinical use by psychologists and psychiatrists. METHOD: This study was conducted as a pilot randomized controlled trial with a pre-test/post-test design, comparing an intervention group to a waitlist control group. The sample included 32 outpatients aged 18-40 years diagnosed with GAD at Zareh Hospital's psychotherapy clinic. Participants were randomly assigned to an experimental group (n = 16) and a control group (n = 16). The experimental group received eight weekly sessions of Metacognitive Therapy (MCT), while the control group was placed on a waitlist and received no intervention during the study period. Data were collected using the Generalized Anxiety Disorder Scale, the Distress Tolerance Scale, and the Medication Adherence Measure. Data analysis was performed with SPSS version 26 using MANCOVA. RESULTS: Results showed that MCT significantly improved emotional distress tolerance. In the experimental group, the mean score increased from 30.94 ± 4.28 at pre-test to 52.75 ± 6.89 at post-test (95% CI for estimated marginal mean: 52.06-55.47), while in the control group the mean score changed from 32.63 ± 5.56 to 33.81 ± 6.73 (95% CI: 31.09-34.51). This difference was significant (F = 109.82, η²=0.80, P < 0.001). MCT also significantly improved medication adherence. In the experimental group, the mean score increased from 3.06 ± 1.88 to 7.81 ± 1.94 (95% CI: 7.38-8.64), whereas in the control group it changed from 3.50 ± 1.37 to 3.63 ± 1.54 (95% CI: 2.79-4.05). This difference was significant (F = 311.16, η²=0.92, P < 0.001). CONCLUSION: Conclusion Preliminary findings suggest that MCT may enhance both emotional and behavioral outcomes in GAD. If replicated in larger trials, its application in clinical practice could help mental health professionals address major challenges such as distress intolerance and poor medication adherence, potentially reducing patient distress and promoting long-term engagement in treatment. TRIAL REGISTRATION: Iranian Registry of Clinical Trials (IRCT), IRCT20231128060213N1, registered on 05 January 2024 (retrospectively registered).