Personality disorders (PDs) have a prevalence of approximately 9% in the United States. Patients with these disorders frequently are encountered in the family medicine setting. It is thought that a combination of unknown genetic factors and life experiences, particularly adverse childhood experiences, contribute to PD development. The diagnosis of patients with PD is complex and should be performed by a psychiatry or psychology subspecialist. The (Fifth Edition) () divides the 10 PDs into three clusters based on descriptive commonalities. Individuals with cluster A PDs often are described as odd or eccentric. Individuals with cluster B PDs often appear dramatic and emotional and exhibit erratic behavior. Individuals with cluster C PDs often appear anxious and fearful. Family physicians should be able to recognize patients with characteristics suggestive of PDs who should be considered for screening. Management consists mainly of psychotherapy. Use of pharmacotherapy is recommended in some specific situations. Patients with PDs can have significant disabilities, medical comorbidities, and high rates of health care use. They have a higher incidence of sleep disorders, chronic pain, chronic health conditions, and obesity than patients in the general population.