Neurophysiological Signatures of Mindfulness-Based Stress Reduction in Adults with Autism: Putative Mechanism of Anxiety Alleviation

Objectives Mindfulness-based therapies can reduce depression and anxiety in adults with autism spectrum disorder (ASD). However, the underlying neurophysiological mechanisms have yet to be fully characterized. While mindfulness-related improvements are theorized to be derived from alterations to resting-state networks—especially within the default mode network (DMN)—in other clinical populations, it is unclear if changes in DMN neurophysiology relate to symptom reduction in autistic adults. Method In this randomized controlled trial, 96 adults with ASD were assigned to either a Mindfulness-Based Stress Reduction (MBSR) or a social support and relaxation education (SE) active control group. Resting-state electroencephalography recordings and self-report questionnaires assessing depression (BDI-2) and trait anxiety (STAI-2) were collected before and after the 8-week intervention to examine neurophysiological correlates of DMN activity—namely, gamma and high beta (beta-2) power across midline electrodes. Results Spectral power analysis of neurophysiological signatures of DMN activity from 62 participants (MBSR n =29; SE n =33) identified distinct MBSR-induced reductions in frontal and parietal gamma power and frontal beta-2 power relative to the SE group. Both MBSR and SE groups showed reductions in central beta-2 and gamma-band power, suggestive of an overlapping mechanism. MBSR-specific decreases in parietal gamma power were associated with alleviation of anxiety symptoms. Conclusions Findings suggest distinct neurophysiological correlates of mindfulness training implicating the DMN and point to a potential anxiolytic mechanism in adults with ASD. Preregistration NCT04017793