Alternative model for personality disorders and drug use among the homeless individuals.

OBJECTIVES: This article aims to examine the contribution of the Alternative Model for Personality Disorders (AMPD) in relation to social exclusion and substance use. Indeed, numerous studies converge in highlighting a higher prevalence of personality disorders and substance use among homeless individuals. Since its publication in 2013 the DSM-5 has proposed an Alternative Model for Personality Disorders, allowing for an assessment of personality based on two criteria: the level of personality functioning (Criterion A) and pathological personality traits (Criterion B). The tools developed for this model - the Level of Personality Functioning Scale Brief Form and the Personality Inventory for DSM-5-Brief Form - have been validated in French, enabling their use in clinical research on French-speaking populations.

METHODS: The LPFS-BF and the PID-5-BF were administered to 30 voluntary residents of social reintegration centers. Additionally, a control group of 30 individuals from the general population was selected to ensure gender and age homogeneity between the groups. Fisher's exact test, binomial logistic regression analysis, and linear regression analysis were conducted to explore the relationships between personality factors, substance use, and precariousness.

RESULTS: The analysis of mean scores did not reveal significant personality differences between residents in social reintegration centers and the general population; only substance use was found to be significantly higher among homeless individuals (P>001). Fisher's exact test confirmed the relationship between social exclusion, substance use, and the risk of personality disorders (P>001). A high-risk score for personality disorders was associated with a more than ninefold increase in the likelihood of high-risk substance use (relative risk=9.63, 95% CI: 1.5-63.5) among homeless individuals. Binomial logistic regression analysis identified self-direction as a protective factor against precariousness, whereas disinhibition was identified as a risk factor. Specifically, the combination of low self-direction and high disinhibition appeared to increase the risk of homelessness. Finally, self-direction (P=0.012), negative affectivity (P=0.047), and detachment (P=0.034) were found to play a significant role in the risk of developing a substance use disorder (n=60). Self-direction emerged as a key factor in the relationship between substance use and precariousness.

CONCLUSIONS: These results highlight the relevance of the Alternative Model for Personality Disorders (AMPD) in understanding the interactions among psychosocial difficulties, substance use, and personality. In particular, they emphasize that among homeless individuals an increased risk of personality disorders is closely associated with risky substance use. Furthermore, self-direction emerges as a key factor in mitigating vulnerability to precariousness, whereas disinhibition constitutes a risk factor. These findings offer promising avenues for the development of targeted interventions aimed at enhancing personal resources and reducing risky behaviors among this highly vulnerable population. The issue of the homeostatic function of personality also arises and warrants investigation in future research.