NBPTS School Counseling Practice Test

Understanding how personality disorders are grouped helps clinicians recognize patterns. In DSM-5, personality disorders are organized into three clusters based on similar traits. The trio Paranoid, Schizoid, and Schizotypal fall into Cluster A—the odd or eccentric cluster. Paranoid PD is marked by pervasive mistrust and suspicion of others; Schizoid PD features social detachment and a restricted range of emotional expression; Schizotypal PD shows odd or eccentric thinking, unusual beliefs, and discomfort with close relationships. Together these conditions share a tendency toward odd or eccentric presentation, which defines this cluster. The other clusters cover quite different patterns: Cluster B is dramatic, emotional, and erratic—such as antisocial, borderline, histrionic, narcissistic; Cluster C is anxious or fearful—such as avoidant, dependent, obsessive-compulsive. Therefore, the cluster that includes those three disorders is the one described as odd or eccentric.