This document provides an overview of personality disorders, including their definition, classification, causes, and treatment. It discusses the main personality disorder clusters (A, B, and C), describing the key features of disorders within each cluster such as paranoid, schizoid, borderline, narcissistic, and obsessive-compulsive personality disorders. The document also covers the genetic and environmental factors involved in the development of these conditions, their prevalence rates, and challenges with treatment, which typically involves supportive psychotherapy rather than a focus on past issues. Pharmacological interventions may help specific symptoms but are generally not effective as a standalone treatment.