Personality disorders and treatment drop out in the homeless

The homeless drop out of treatment relatively frequently. Also, prevalence rates of personality disorders are much higher in the homeless group than in the general population. We hypothesize that when both variables coexist — homelessness and personality disorders — the possibility of treatment drop out grows. The aim of this study was to analyze the hypotheses, that is, to study how the existence of personality disorders affects the evolution of and permanence in treatment. One sample of homeless people in a therapeutic community (N = 89) was studied. The structured clinical interview for the diagnostic and statistical manual of mental disorders (DSM-IV-TR) was administered and participants were asked to complete the Millon Clinical Multiaxial Inventory-II (MCMI-II). Cluster B personality disorders (antisocial, borderline, and narcissistic) avoided permanence in the treatment process while cluster C disorders, as dependent, favored adhesion to the treatment and improved the prognosis. Knowledge of these personality characteristics should be used to advocate for better services to support homeless people and prevent their dropping out before completing treatment.