Changes in resting functional connectivity during abstinence in stimulant use disorder: A preliminary comparison of relapsers and abstainers

Background: Previously identified resting functional connectivity (FC) differences in individuals with stimulant use disorder (SUD) suggest an imbalance in neural regions that mediate behavioral aspects relevant to addiction such as emotion regulation and reward processing. There is a need to further investigate these differences across time between those that relapse and those that do not. This is the first longitudinal study of recently abstinent SUD (SUD-RA) that identifies specific FC changes in subsequent relapsers (vs abstainers). We hypothesized that (1) subsequent relapsers (vs abstainers) will show lower FC of emotion regulation regions and higher FC of reward processing regions and (2) FC differences would be more evident across time. Methods: We examined resting FC in 18 SUD-RAs (8 females, age: M= 22.05. ± 2.64) and 15 non-substance abusing controls (NSAC; 5 females, age: M= 24.21. ± 5.76) at Time 1 (abstinent ~5 weeks). Fourteen NSAC and 12 SUD-RAs were re-examined at Time 2 (abstinent ~13 weeks). With seed-based FC measures, we examined FC differences between SUD-RAs that abstained or relapsed over the subsequent 6 months. Results: Relapsers (vs abstainers) had higher FC between (1) nucleus accumbens (NAcc) and left frontopolar cortex (FPC), (2) NAcc and posterior cingulate gyrus and (3) subgenual anterior cingulate and left FPC at Time 1. Relapsers (vs abstainers) showed larger reduction in FC strength within these regions across time. Conclusions: Resting FC reduction found in relapsers (vs. abstainers) from 5 to 13 weeks of abstinence may be a biological marker of relapse vulnerability. These preliminary findings require replication with larger sample sizes.