Cognitive behavioral therapy, mindfulness, and cortisol habituation: A randomized controlled trial.

BACKGROUND: Hypothalamic-pituitary-adrenocortical (HPA) axis dysregulation is associated with disease and may be indexed by poor cortisol habituation (i.e., a failure to show decreased responding with repeated stressor exposure). Thus, stress management training that can enhance HPA axis habituation may benefit health. To date, the effects of Mindfulness Based Stress Reduction (MBSR) and Cognitive Behavioral Therapy (CBT) interventions on HPA axis habituation remain untested. To test the effects of MBSR and CBT on HPA axis habituation, the present study used a parallel arm randomized controlled trial. METHODS: Healthy adults reporting moderate-to-high stress (n = 138) were randomly assigned to a 6-week MBSR intervention, a 6-week CBT intervention, or Waitlist control group. Post-intervention, participants completed a social-evaluative performance stressor during each of two laboratory visits scheduled 48-h apart. Salivary cortisol was collected pre-stressor, and 25, 35, and 60 min post-stressor onset during each visit. Final analyses included 86 participants who completed procedures up to the first laboratory visit. RESULTS: Relative to the control condition, both MBSR and CBT groups showed greater cortisol habituation. The MBSR group exhibited marginally greater habituation than the Waitlist group in cortisol samples corresponding to the recovery time points (35 and 60 min post-stressor onset). In contrast, the CBT group showed greater habituation than the Waitlist across all sampling timepoints collected (pre-stressor, 25, 35, and 60 min post-stressor onset). Yet, the CBT group also demonstrated elevated pre-stressor cortisol during the first visit. CONCLUSIONS: Results suggest that MBSR and CBT interventions promote greater HPA axis habituation relative to no training, but do not reduce overall cortisol output (i.e., across both visits). Observed differences between CBT and MBSR training in relation to cortisol habituation are discussed.

Trait mindfulness predicts the presence but not the magnitude of cortisol responses to acute stress.

BACKGROUND: Mindfulness, or the practice of observing present moment experiences with acceptance, is thought to improve health at least partially by limiting hypothalamic-pituitary-adrenal (HPA) axis over-responsiveness during episodes of acute stress. However, models of allostatic load suggest that HPA axis under-responsiveness can also be detrimental to health, and the relationship between mindfulness and cortisol under-responsiveness has yet to be examined. The present study therefore aimed to address this knowledge gap, and to revisit the relationship between mindfulness and acute cortisol response magnitude while excluding (or statistically controlling for) individuals displaying HPA axis under-responsiveness. METHODS: Participants (124 healthy undergraduate students) were subjected to a stressful speech task, and completed a trait mindfulness questionnaire. Salivary cortisol was collected 0, +15, +25, +40, and +55 min post-stressor onset. RESULTS: Greater trait mindfulness was associated with greater odds of displaying a cortisol response relative to none, but was unrelated to the magnitude of cortisol responses among those who displayed an acute response. CONCLUSIONS: In the present sample, trait mindfulness was associated with cortisol responses, but this was driven by the fact that subjects low in mindfulness were more likely to be non-responders. Contrasting the effects of mindfulness on the presence (i.e., present vs. absent) and the degree (i.e., magnitude) of acute stress responses may therefore be warranted in future research.

Trait rumination moderates the effect of mentation type on heart rate responses to stressor recall.

Ruminative thought about stressors has been linked to extended post-stressor cardiovascular activation, which in turn predicts negative long-term health outcomes. Past work indicates that the nature of thought (mental imagery or verbal thought) may shape cardiovascular responses. Some evidence suggests that individuals with rumination tendencies may be especially vulnerable to stress-related cardiovascular activation, although it is unclear to what extent type of thought (imagery or verbal thought) influences this relationship. This study included a laboratory stressor followed by a stressor recall task in which mentation type was manipulated. Healthy undergraduate students (N = 138; 47% female) underwent a speech stressor and then were randomly assigned to complete a stressor recall task using either mental imagery or verbal-linguistic mentation. Heart rate (HR) and blood pressure (BP) were measured throughout. Self-report trait rumination was measured at baseline. Results indicated that trait rumination and mentation type interacted to predict HR. Individuals with high trait rumination scores had significantly greater increases in HR during the verbal-linguistic conditions compared to the mental imagery conditions. There were no mentation type differences in the low trait ruminators, no differences in BP and no main effects of trait rumination. Results suggest that mentation type may be a key in understanding the relationship between rumination and cardiovascular activation, especially for trait ruminators.

Cardiovascular and affective consequences of ruminating on a performance stressor depend on mode of thought.

Psychological detachment from work is important for facilitating recovery. This can be threatened by rumination, or thinking about the day's stressors. Rumination may lead to distress, fatigue and extended activation of stress-related systems, but findings are not unequivocal. Level of construal (abstract or concrete) and type of mentation (imagery or verbal thought) used during stressor-focused rumination may shape physiological and affective responses and impact recovery. This study tested whether blood pressure (BP) and anxiety responses to stressor-focused rumination differ by mentation type and construal level. Healthy undergraduates (n = 136) performed a speech stressor and then completed a rumination task in one of four randomly assigned conditions: concrete imagery, abstract imagery, concrete verbal thought or abstract verbal thought. Anxiety and continuous BP were assessed. Concrete rumination led to greater BP, whereas rumination with abstract construals led to lower BP. Furthermore, participants in the abstract conditions had greater increases in anxiety following stressor-focused rumination than in the concrete conditions. Results suggest that the immediate physiological and psychological consequences of stressor-focused rumination depend upon mode of thought.