Change in Personality Functioning During Residential Substance Use Disorder Treatment: An Observational Study.

BACKGROUND: Successful treatment of Substance Use Disorder (SUD) requires not only a reduction in substance use but also improvements in personality functioning. This study aimed to identify which aspects of personality functioning improve during residential SUD treatment. METHODS: The study was conducted at a Norwegian residential SUD treatment facility offering 3-6-month programs for young adults. The sample consisted of 80 patients diagnosed with SUD (mean age = 24 years; 62.5% male, 37.5% female). Personality functioning was assessed using the Severity Indices of Personality Problems (SIPP-118) at the start of treatment and after an average of 150 days (median = 103 days) in residential care. RESULTS: According to the paired-sample t-tests, there were statistically significant improvements in 11 out of 16 SIPP-118 facets (subscales). Effortful control (p < 0.001, d = 0.50) and Emotion regulation (p = 0.002, d = 0.36) were among the facets with the greatest improvements. In contrast, no significant changes were observed in Intimacy or Enduring relationships. CONCLUSIONS: The findings suggest that personality functioning related to self-control improves during residential SUD treatment, whereas relational capacity showed minimal change over time.