Substance Use Disorders and Treatment Expectations: Towards a New Understanding of Cocaine Use Disorder

How treatment outcomes can be predicted in patients with cocaine use disorder based on their treatment expectations at baseline

This study aimed to explore the role of pre-treatment expectations in predicting treatment outcomes for cocaine use disorder (CUD) patients undergoing high-frequency repetitive transcranial magnetic stimulation (rTMS). We validated the Stanford Expectations of Treatment Scale (SETS) within our population (Italian patients with CUD), employing a two-dimensional positive and negative expectations model. The confirmatory factor analysis (CFA) demonstrated a strong model fit for the SETS, and internal consistency was satisfactory. Moreover, a significant correlation was found between positive pre-treatment expectations and quality of life as measured by the Quality of Life Enjoyment and Satisfaction Questionnaire—Short Form (Q-LES-Q-SF), supporting a suboptimal concurrent validity. However, the relationship between negative pre-treatment expectation and Q-LES-Q-SF only approached statistical significance. Overall, the trends of the correlation were consistent with previous research on the impact of positive and negative expectancies (Younger et al., 2012). The logistic regression analysis revealed that positive pre-treatment expectations significantly diminished the likelihood of a positive urine test by the end of the first week of treatment, whereas negative expectations increased the risk. Cocaine craving at baseline was also a significant predictor of continued use, as it increased the risk of positive urine tests at the end of the week. A linear mixed model analysis over 90 days showed a significant reduction in craving with time, particularly in patients with higher positive expectations and higher incidence of rTMS sessions. Although our findings are consistent with existing literature on the benefits of positive expectations in clinical outcomes, the study presents limitations, such as the absence of a control sham group. Future studies should investigate dynamic changes in expectations throughout treatment and validate the SETS in more diverse populations to enhance its applicability and generalizability. Overall, these results emphasize the importance of addressing patient pre-treatment expectations in clinical interventions for addiction recovery, suggesting that fostering positive beliefs may bolster treatment compliance and outcomes.