Dissociable neural substrates of opioid and cocaine use identified via connectome-based modelling

Opioid use disorder is a major public health crisis. While effective treatments are available, outcomes vary widely across individuals and relapse rates remain high. Understanding neural mechanisms of treatment response may facilitate the development of personalized and/or novel treatment approaches. Methadone-maintained, polysubstance-using individuals (n=53) participated in fMRI scanning before and after substance-use treatment. Connectome-based predictive modeling (CPM)—a recently developed, whole-brain approach—was used to identify pre-treatment connections associated with abstinence during the 3-month treatment. Follow-up analyses were conducted to determine the specificity of the identified opioid abstinence network across different brain states (cognitive vs. reward task vs. resting-state) and different substance use outcomes (opioid vs. cocaine abstinence). Post-treatment fMRI data were used to assess network changes over time and within-subject replication. To determine further clinical relevance, opioid abstinence network strength was compared to healthy subjects (n=38). CPM identified an opioid abstinence network (p=.018), characterized by stronger within-network motor/sensory connectivity, and reduced connectivity between the motor/sensory network and medial frontal, default mode and frontoparietal networks. This opioid abstinence network was anatomically distinct from a previously identified cocaine abstinence network. Relationships between abstinence and opioid and cocaine abstinence networks replicated across multiple brain states but did not generalize across substances. Network connectivity measured at post-treatment related to abstinence at 6-month follow-up (p<.009). Healthy comparison subjects displayed intermediate network strengths relative to treatment responders and non-responders. These data indicate dissociable anatomical substrates of opioid versus cocaine abstinence. Results may inform the development of novel opioid-specific treatment approaches to combat the opioid epidemic.