Investigating the prevalence of personality disorders among psychiatric inpatients and their non-inpatient family members

Introduction: This study aimed to determine the prevalence of personality disorders among psychiatric inpatients and their non-inpatient family members. Materials and Methods: In this descriptive correlation study, 100 psychiatric patients hospitalized at the Ibn-e-Sina Psychiatric Hospital in Mashhad city-Iran, and 100 of their non-admitted family members were selected through random sampling. The research tool was the Millon Clinical Multiaxial Inventory-III (MCMI-III). The data were analyzed through descriptive statistics, T-test, and Mann-Whitney test.  Results: The findings showed that the prevalence of personality disorders among hospitalized patients was 69%, and among their non-hospitalized family members was 63%. The most common disorders among the patients were depressive personality disorder (18%) and obsessive-compulsive disorder (16%), and among the family members of patients, histrionic and obsessive-compulsive disorders (23%). There were significant differences between patients and family members in sadistic, schizotypal, borderline, depressed, dependent, antisocial, negativistic, self-defeating, and paranoid personality disorders (P 0.05). However, in obsessive-compulsive, histrionic, avoidant, schizoid, and narcissistic disorders, there were no significant differences (P 0.05). Conclusion: Based on the findings, the prevalence rates of personality disorders among hospitalized psychiatric patients are high. Also, it is considerable that personality disorders are prevalent among family members of hospitalized psychiatric patients.