Increases in striatal response to reward anticipation relate to reductions in impulsivity in women with substance use disorders

Background and Aims: Impulsivity and neural reward reactivity are considered important factors in the development and maintenance of substance use disorders (SUDs) and may be predictive of treatment response. However, relationships between treatment response, impulsivity, and reward reactivity are understudied in women with SUDs, where there may be unique clinical concerns such as higher incidences of trauma than men. Our study aimed to characterize relationships between neural responses to reward anticipation and changes in behavioral and clinical outcomes following treatment.Design: Multimodal longitudinal, within-subjects study. Follow-up measurement took place one year after the start of a criminal diversion SUD treatment program.Setting: The study was conducted in Tulsa, Oklahoma. Participants: Eighty-three adult women who completed a criminal diversion program that included comprehensive treatment for SUDs.Measurement: The primary variable of interest was nucleus accumbens (NAc) reactivity to reward and loss anticipation during a monetary incentive delay (MID) task examined via functional magnetic resonance imaging (fMRI) early in treatment (baseline) and one year later (follow-up). Outcomes included measures of substance use severity, positive and negative urgency, and posttraumatic stress disorder (PTSD) symptoms. Findings: At baseline, more severe substance use symptoms were associated with elevated NAc reward anticipation while greater PTSD symptoms were associated with lower NAc loss anticipation. Symptoms of PTSD, substance use, and urgency significantly decreased by one-year follow-up (η_p^2>0.22). Increases in NAc reward anticipation over time were associated with lower urgency at follow-up, regardless of PTSD symptom levels (η_p^2>0.03). Whole-brain analyses also showed that increased striatal reward anticipation over time was associated with lower positive urgency at follow-up. PTSD symptom severity moderated the relationship between changes in NAc loss anticipation and negative urgency.Conclusions: Following a one-year SUDs treatment program , a sample of women showed lower impulsivity associated with increased striatal responses to reward anticipation. This suggests that NAc reactivity to anticipation of non-drug outcomes may offer a potential neural target for enhancing SUDs treatment outcomes for women, while loss-related reactivity may be particularly relevant in the presence of co-occurring PTSD.