Stimulating Mindfulness-To-Meaning: Noninvasive Brain Stimulation Targeting the Upward Spiral of Mindful Positive Emotion Regulation
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Authors
McDonald, Mollie A.
Issue Date
2024
Type
Dissertation
Language
Keywords
Generalized Anxiety , Mind-wandering , Mindfulness , Noninvasive Neurostimulation , TDCS , Worry
Alternative Title
Abstract
Objectives: Worry is highly prevalent and associated with internalizing disorders, such as generalized anxiety disorder. Foremost treatments for worry include mindfulness-based interventions. Paradoxically, engagement in mindfulness practices may be especially difficult for individuals with negative repetitive thinking habits, like worry. Mindfulness training may be improved for chronic worriers by stimulating neural areas associated with a mindful state, such as the left dorsolateral prefrontal cortex (L-DLPFC). Beyond its association with mindful states, L-DLPFC activation is associated with the underlying cognitive processes of a leading theory explaining how mindfulness produces psychological benefits: mindfulness-to-meaning theory. Cognitive processes improved by mindfulness and associated with L-DLPFC activation include inhibition of automatic responses (inhibitory control) and reinterpretation of stressors in a positive light (positive reappraisal). Inhibitory control and positive reappraisal are particular areas of difficulty for chronic worriers. Improvements in these areas may facilitate chronic worriers' ability to disengage from worry and instead derive meaning from stressors, which can contribute to improved psychological functioning. Therefore, transcranial direct current stimulation (tDCS) targeting the L-DLPFC was hypothesized improve engagement in mindfulness practices, mindfulness-to-meaning processes (e.g., decentering), and psychological functioning (e.g., decreased generalized anxiety) in chronic worriers. Methods: Adult novice meditators ( N = 64) with clinically elevated worry were randomized to one of four groups using a 2 (mindfulness vs mind-wandering) x 2 (active vs sham tDCS) design. At an initial lab visit, participants listened to instructional recordings during stimulation, then completed three remote follow-ups over the course of one week. Follow-ups included additional shorter mindfulness and mind-wandering practices without stimulation. Results: No changes in decentering, inhibitory control, or positive reappraisal were observed. However, among participants who received mindfulness, active stimulation enhanced engagement, reductions in generalized anxiety, and increases in trait mindfulness. Additionally, although no potentiating effect was observed, mindfulness and active tDCS separately contributed to reducing catastrophizing tendencies. Contrary to hypotheses, however, mind-wandering also produced beneficial outcomes, including increases in trait mindfulness. Conclusions: Importantly, the current findings suggest that supplementing the first mindfulness session with L-DLPFC stimulation (vs sham) improved engagement and reduced generalized anxiety symptoms during a brief mindfulness intervention. Unexpectedly, mind wandering increased trait mindfulness. Therefore, rather than functioning as an inactive control condition as intended, deliberate mind wandering may instead imitate aspects of mindfulness interventions, particularly among chronic worriers. No improvements were observed in decentering, inhibitory control, and positive reappraisal, which are central mindfulness-to-meaning processes. However, reductions in generalized anxiety and catastrophizing are promising outcomes for chronic worriers. Future studies should explore whether increased dosage and/or extended follow-ups beyond the first week of practice may demonstrate improvements in the cognitive processes which are central to mindfulness-to-meaning theory.