Clinical utility of assessing changes of personality functioning during substance misuse treatment

Dimensional models for classifying personality have received extensive empirical support in the treatment of substance misuse. However, we do not currently understand whether and which dimensions of personality functioning are amenable to change. The aim was to examine whether there are clinically significant changes between pre- and during-treatment and assess whether these differ between those completing or dropping out of treatment. From the 200 participants from the outpatient and 340 from the inpatient treatment, a purposeful selection was utilised of 75 cases that participated in both phases and had complete datasets of the assessment battery. A quantitative multi-site individual follow-up design allowed the examination of the potential effects of treatment in personality functioning as well as the degree of clinical significant change of personality functioning. We use Jacob and Truax’s formula of reliable and clinically significant change. Five independent mixed between-within subject analyses of variance were performed. All personality adaptations changed towards higher-functioning levels, except Social Concordance, which remained stable. Compared to those dropping out, completers had significantly more changes towards functional characteristic adaptations and higher clinical improvement. The persistence of maladaptive characteristic adaptations may be an important risk marker for poor treatment outcomes, requiring therapeutic attention.