Posted 03.14.2018 | by AMRA

The United States is in the midst of an opioid epidemic, with over 42,000 opioid overdose related deaths in 2016. There is a clear need for innovative approaches to help deal with the problems of substance dependency and misuse. Mindfulness-based interventions are sometimes used as adjunctive treatments for substance use disorders, but little is known about how these interventions affect the brains of substance users.

Fahmy et al. [Addictive Behaviors] used structural magnetic resonance imaging (MRI) to investigate brain changes in opiate dependent patients undergoing either treatment-as-usual (TAU), or treatment-as-usual plus Mindfulness-Based Stress Reduction (MBSR).

MRI data were analyzed to identify structural changes in the cellular networks connecting brain regions. The researchers limited their investigation to regions previously shown to be of interest in addiction and mindfulness research. They also looked at whether structural brain network changes were accompanied by meaningful changes in personality traits relevant to recovery and relapse.

The study followed 28 opiate dependent patients (average age = 30 years; 89% male) in a four-week inpatient substance treatment program in Cairo, Egypt. Half the participants were assigned to treatment as usual (TAU) and half to MBSR. Assignment was based on order of enrollment in the study and was not strictly random.

Nineteen participants completed their treatments and post-treatment evaluations. There was no difference in treatment dropout rates. TAU included medication and group cognitive behavioral therapy. The MBSR program was a culturally adopted Arabic-language version of MBSR. Participants completed the Freiburg Mindfulness Inventory (FMI), self-reported measures of distress tolerance, sensation seeking, impulsivity, and addiction severity, and underwent MRI scanning before and after treatment.

MBSR participants showed significant strengthening in the brain networks connecting the prefrontal cortex with the anterior cingulate cortex (prefrontal-cingulate network) and the bilateral insular region with the bilateral striatal region (striatal-insular network). These structural changes did not occur in the TAU group.

Additionally, the greater the degree of prefrontal-cingulate network strengthening, the greater the decrease in the use of impulsive behavior as a strategy to decrease unpleasant emotional states (r=.74; a large effect).

Self-reported mindfulness scores on the FRI improved significantly over time for both groups (average TAU increase = 5 points; average MBSR increase = 8 points), as did measures of distress tolerance. MBSR participants’ tendency to resort to impulsive behavior to distract from unpleasant emotions declined significantly over time, whereas a similar trend within the TAU group did not reach significance. The difference in impulsivity change rates between groups was not significant.

The study demonstrates that four weeks of MBSR can strengthen brain networks associated with executive control and interoceptive awareness in patients with opiate dependence. There was a strong association between strengthening the prefrontal-cingulate network and decreasing impulsivity. This makes intuitive sense given that the prefrontal cortex and cingulate cortex are associated with controlling attention, reducing distraction and inhibiting impulsive responding. These are all important functions in resisting temptation and preventing relapse.

The finding that MBSR also strengthens the striatal-insular network is important because decreased striatal and insular volumes have been previously noted in patients with alcohol dependence. The study is limited by its lack of randomization, small sample size, and lack of statistical correction for multiple comparisons.

Reference:

Fahmy, R., Wasfi, M., Mamdouh, R., Moussa, K., Wahba, A., Wittemann, M., . . . Sambataro, F. (2018). Mindfulness-based interventions modulate structural network strength in patients with opioid dependence. Addictive Behaviors.

[Link to abstract]