Knowledge is lacking regarding who is most likely to benefit from mindfulness-based interventions (MBIs) and who may be at risk of harm. Several studies suggest that patients with recurrent depression in remission are more likely to benefit from Mindfulness-Based Cognitive Therapy (MBCT) if they have histories of childhood trauma.

However, one study on MBCT for active depression found that patients with histories of childhood trauma had poorer treatment outcomes. Additionally, preliminary data suggest that meditators with histories of childhood trauma may be more vulnerable to meditation-related adverse experiences.

Canby et al. [PLOS ONE] conducted two studies to examine whether histories of childhood trauma and PTSD symptoms predict variability in MBCT outcomes in patients with active depression. The first study explored childhood trauma as a predictor of depressive symptom improvement and therapy attrition, while the second, larger replication study also assessed meditation-related adverse experiences and side effects.

In the first study, the researchers randomly assigned 52 patients (average age = 47 years; 79% female) with histories of recurrent depression in partial remission to either an 8-week MBCT program or a waitlist control. At baseline, patients were assessed using the Beck Depression Inventory (BDI), a structured clinical interview, and a self-report measure of childhood trauma (including life-threatening illness or injury, the death of a loved one, physical/sexual abuse, rape, and assault). Post-treatment outcomes were assessed using the BDI.

Results showed that the MBCT group significantly lowered their average BDI scores more than controls. Childhood trauma history and histories of physical and sexual abuse scores were associated with significantly poorer BDI improvement in the MBCT group. In the control group, childhood trauma and sexual abuse scores were associated with significantly poorer improvement over time. Trauma histories did not predict study dropout rates in either condition.

In study 2, part of a larger dismantling study, the researchers randomly assigned 104 patients with mild-to-severe depression or high negative affect (average age = 40 years; 74% female) to MBCT, MBCT with only focused-attention meditation, or MBCT with only open-monitoring meditation. While patients who met the full diagnostic criteria for PTSD were excluded, those with past or sub-clinical PTSD were included.

Participants completed a trauma questionnaire, a self-report measure of depressive symptoms, and a structured clinical interview at baseline. These assessments were repeated at 4 weeks, 8 weeks, and 3-months. At the 3-month assessment, participants also completed a questionnaire assessing meditation-related adverse experiences (MBAEs), meditation-related side effects (MRSEs), and long-lasting adverse effects. 

Results showed that 58% of participants reported unpleasant MRAEs, 37% reported MRAEs that negatively impacted daily functioning,14% reported adverse effects lasting more than a day, 9% reported adverse effects lasting more than a week, and 6% reported adverse effects lasting over a month. Long-lasting adverse effects included executive dysfunction, insomnia, emotional blunting, identity disturbance, anxiety, time-space distortions, traumatic re-experiencing, derealization, and social impairment.

Average depressive symptoms improved significantly in all groups at all time points. Participants with greater total trauma, sexual abuse, or emotional neglect scores improved significantly less on self-reported depression scores. All trauma types predicted a greater likelihood of MSREs, while all trauma variables except physical abuse predicted a greater likelihood of unpleasant MRAEs. MRAEs that interfered with daily functioning were predicted by total trauma, emotional abuse, sexual abuse, and current and past PTSD symptoms.

Persistent adverse effects were predicted by total trauma history, emotional abuse, and current and past PTSD symptoms. Patients with past histories of sexual abuse were more likely to drop out of the study.

Together, the studies show that actively depressed patients with childhood abuse histories and PTSD symptoms are significantly less likely to benefit from MBCT and more likely to experience adverse meditation-related effects. The second study lacked non-meditation and no-treatment controls so one cannot infer whether a different treatment or the simple passage of time might have led to similar, lower, or higher rates of adverse experiences. 

Reference:

Canby NK, Cosby EA, Palitsky R, Kaplan DM, Lee J, Mahdavi G, et al. Childhood trauma and subclinical PTSD symptoms predict adverse effects and worse outcomes across two mindfulness-based programs for active depression. PLOS ONE.

Link to study