The effects of Mindfulness-Based Cognitive Therapy on affective memory recall dynamics in depression: a mechanistic model of rumination

Mindfulness-based cognitive therapy (MBCT) helps protect against depression-related deterioration in memory retrieval patterns. In a randomized controlled trial, 29 people with recurrent depression who completed MBCT maintained stable initial affective bias (probability of first recalling a positive or negative word) after a stressor, while 23 wait-list controls showed increased negative bias and decreased positive bias. MBCT also reduced participants' tendency to sustain trains of negative words during free recall, indicating less persistence of negative mind states. These model-based measures of recall dynamics provide detailed insight into how mindfulness may reduce rumination beyond what self-report questionnaires capture.

Study at a glance

Abstract

Objectives: Converging research suggests that mindfulness training exerts its therapeutic effectson depression by reducing rumination. Theoretically, rumination is a multifaceted construct thataggregates multiple neurocognitive aspects of depression, including poor executive control,negative and overgeneral memory bias, and persistence or stickiness of negative mind states.Current measures of rumination, most often self-reports, do not capture these different aspects ofruminative tendencies, and therefore are limited in providing detailed information about themechanisms of mindfulness.Methods: We developed new insights into the potential mechanisms of rumination, based onthree model-based metrics of free recall dynamics. These three measures reflect the patterns ofmemory retrieval of valenced information: The probability of first recall (Pstart) whichrepresents initial affective bias, the probability of staying with the same valence category ratherthan switching, which indicates strength of positive or negative association networks (Pstay);and probability of stopping (Pstop) or ending recall within a given valence, which indicatesdrift persistence or stickiness of a mind state. We then investigated the effects of MBCT(N=29) vs wait-list control (N=23) on these recall dynamics in a Randomized Controlled Trial(RCT) in individuals with recurrent depression. Participants completed a standard laboratorystressor, the Trier Social Stress Test (TSST), to induce negative mood and activate ruminativetendencies. Then, participants completed a free recall task consisting of three word lists. Thisassessment was conducted both before and after treatment or wait-list.Results: While MBCT participant’s Pstart remained relatively stable, controls showed multipleindications of depression-related deterioration towards more negative and less positive bias.Following the intervention, MBCT participants decreased in their tendency to sustain trains ofnegative words