Contents lists available at ScienceDirect Addictive Behaviors journal homepage: www.elsevier.com/locate/addictbeh Mindfulness-based interventions modulate structural network strength in patients with opioid dependence Reham Fahmy a , Maha Wasfi a , Rania Mamdouh a , Kareem Moussa b , Ahmed Wahba c , Miriam Wittemann d , Dusan Hirjak e , Katharina M. Kubera g , Nadine D. Wolf g , Fabio Sambataro f , Robert Christian Wolf g, ⁎ a Department of Psychiatry, Kasralainy Faculty of Medicine, Cairo University, Egypt b Department of Radiology, Kasralainy Faculty of Medicine, Cairo University, Egypt c Psychiatric Hospital Rickling, Rickling, Germany d Department of Psychiatry and Psychotherapy, Saarland University, Homburg, Germany e Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Germany f Department of Medicine (DAME), Udine University, Italy g Center for Psychosocial Medicine, Department of General Psychiatry, Heidelberg University, Germany HIGHLIGHTS • We investigated effects of MBI on brain volume in patients with opioid dependence. • Patients receiving MBI showed distinct structural network changes after treatment. • An increase in striatal and prefrontal network strength was observed. • Prefrontal network strength was associated with impulsivity levels. ARTICLE INFO Keywords: MRI Opiates Source-based morphometry Frontal cortex Striatum Impulsivity ABSTRACT Mindfulness-based interventions (MBI) are increasingly used in the treatment of patients with mental disorders, in particular in individuals presenting with affective disorders or in patients exhibiting abnormal levels of im- pulsive behavior. MBI have been also offered to patients with substance use disorders, where such treatment options may yield considerable clinical effects. Neural effects associated with MBI have been increasingly ac- knowledged, but is unknown whether MBI exert specificeffects on brain structure in patients with substance use disorders. In this study, we investigated 19 inpatients with opioid dependence receiving treatment-as-usual (TAU, n = 9) or additional MBI (n = 10). Structural magnetic resonance imaging data were acquired before and after four weeks of treatment. Source-based morphometry was used to investigate modulation of structural networks after treatment. Both treatment modalities led to significant clinical improvement. Patients receiving MBI showed a significant change in distress tolerance levels. An increase in bilateral striatal/insular and pre- frontal/cingulate network strength was found in patients receiving MBI compared to individuals receiving TAU. Prefrontal/cingulate cortical network strength was associated with impulsivity levels. These findings suggest that MBI can have a recognizable role in treatment of substance use disorders and that neural effects of MBI may be captured in terms of frontostriatal structural network change. 1. Introduction In the past years, mindfulness-based interventions (MBI) have at- tracted substantial clinical and scientific interest (Kurdyak, Newman, & Segal, 2014). Defined as bringing one's complete attention to the ex- periences occurring in the present moment in a non-judgmental and accepting manner, mindfulness-based practices enhance discriminative awareness, while responding to uncomfortable or challenging situations with complete acceptance, thus discouraging the brain's automatic re- sponses and giving way to a novel form of thought and behavior (Witkiewitz, Lustyk, & Bowen, 2013). Distinct effects of mindfulness- based practices on brain activity, both during state mindfulness and as a https://doi.org/10.1016/j.addbeh.2018.02.013 Received 3 November 2017; Received in revised form 7 February 2018; Accepted 7 February 2018 ⁎ Corresponding author at: Center for Psychosocial Medicine, Department of General Psychiatry, Heidelberg University, Vossstrasse 4, 69115 Heidelberg, Germany. E-mail address: christian.wolf@med.uni-heidelberg.de (R.C. Wolf). Addictive Behaviors 82 (2018) 50–56 Available online 08 February 2018 0306-4603/ © 2018 Elsevier Ltd. All rights reserved. T