Gradual improvement in functioning and mental distress during long-term outpatient SUD treatment – A prospective pre-post study

Abstract

Background Globally, outpatient programs for substance use disorder (SUD) treatment have gained prominence. To assess the broader clinical implications of this trend we investigated shifts in functioning experienced by outpatients undergoing treatment. Methods We describe the clinical characteristics of a cohort of 93 SUD patients in a Norwegian outpatient treatment clinic. Using paired-samples t-tests, we examined changes in perceived functioning, mental distress, and other clinically relevant outcome variables in a 5-month time interval during the treatment course. Results We obtained follow-up data for 67 (72%) of the included patients, with no significant difference in patient-related factors between those who completed the treatment course and those who were not assessed at follow-up. Perceived functioning increased significantly from study inclusion (Time 0) (mean 19.8, standard deviation ± 8.8) to its conclusion (Time 1) (24.3, ±9.3; t (66) = 4.5, (95% CI: 2.5–6.5, p < 0.001). We also identified significant improvement in most other measured variables, including mental distress, self-reported sleep quality, restlessness, and obsessive thinking. Substance use–related variables showed a modest, non-significant improvement at T1. Conclusion During a 5-month course of outpatient treatment, patients’ subjective experience of functioning improved significantly. Those with the lowest functioning levels at T0 improved the most. Structured monitoring may be a valuable clinical tool for personalizing intervention, enhancing treatment outcomes, and supporting the clinical decision-making process.