<h3>Introduction</h3> Non-motor symptoms of Parkinson's disease (PD) are common and may lead to increased disability and functional impairment. Over half of people with PD experience anxiety and/or depression. Mindfulness-based interventions have been shown to alleviate physical and psychological symptoms of cancer, cardiovascular disease, chronic pain, anxiety, and depressive disorders. Mindfulness-based cognitive therapy (MBCT) is a manualized intervention conducted in 8-week group sessions, along with participant independent daily practice. MBCT combines mindfulness practice with cognitive therapy principles and has been shown to prevent the relapse of recurrent depression and improve anxiety. MBCT has been studied in patients with neurological diseases, including PD, albeit not extensively. In this pilot study, we aimed to investigate the effectiveness of MBCT in reducing anxiety and/or depression in people with PD. <h3>Methods</h3> A modified MBCT intervention was designed and offered to participants with PD and mild-moderate anxiety and/or depressive symptoms from the San Francisco Bay Area. IRB approval was obtained. Participants were recruited from local neurology clinics and through PD support groups. Two 8-week long MBCT groups were conducted, using a protocol adapted to the specific needs of people with PD. Participant demographic variables, prior experience with mindfulness, and pre- and post-intervention behavioral measures were collected (GAD-7, PHQ-9, and Five Facet Mindfulness Questionnaire-15 - FFMQ-15). A participant satisfaction survey was administered after the completion of the MBCT course. Descriptive analytics were used to analyze demographic and clinical variables and participant satisfaction survey responses. To make use of all available data, PHQ-9, GAD-7, and FFMQ scores pre- and post-intervention were compared using mixed-effects models implemented with PROC MIXED in SAS Version 9.4. This approach accounted for the correlated structure of the data due to repeated measures, allowed for missing data, and accommodated heterogeneous variances across assessment times. <h3>Results</h3> Of the 16 participants enrolled (8 per group), 15 completed the MBCT intervention (1 participant withdrew). Participants attended on average 7 of the 8 sessions. The statistical analysis revealed: • Significant reduction in PHQ-9 score post-intervention, compared to pre-intervention (<i>p</i> < 0.05) • Reduction in GAD-7 mean score post-intervention, compared to pre-intervention • Significant increase in FFMQ mean score post-intervention, compared to pre-intervention (<i>p</i> < 0.01). • 12 (80%) participants were very satisfied, 2 (13.3%) were satisfied, and 1 (6.7%) was dissatisfied with the overall MBCT course. • 14 (93.3%) participants planned to continue to practice mindfulness after completing the course, and 14 (93.3%) would recommend this intervention to family members or friends with PD. Tables 1-2 present the results. Table 1. Participant characteristics. Table 2. Behavioral measure scores, pre- and post-intervention. <h3>Conclusions</h3> At the completion of an 8-week modified MBCT course for people with PD, there was significant reduction in depressive symptoms. This pilot study shows that this is a feasible intervention for this population, met with high participant satisfaction. Discussion: COVID-19 pandemic started during the second MBCT group. Participants commented that this had increased their anxiety, which likely affected post-intervention GAD-7 scores in that group. The last 2 sessions were modified for online delivery, showing the versatility of this approach. Further research is needed to explore the effectiveness of MBCT in reducing anxiety and/or depressive symptoms in people with PD. <h3>Funding</h3> The Parkinson's Foundation