Which of the following is NOT one of the three personality disorders in cluster A?

The correct answer is that narcissistic personality disorder is not one of the three disorders categorized under cluster A. Cluster A personality disorders are characterized by odd or eccentric behaviors and include paranoid personality disorder, schizoid personality disorder, and schizotypal personality disorder.

Paranoid personality disorder involves a pattern of distrust and suspicion of others. Schizoid personality disorder is characterized by a lack of interest in social relationships, a tendency towards a solitary lifestyle, and emotional coldness or detachment. Schizotypal personality disorder includes odd thinking, eccentric behaviors, and discomfort in close relationships, often incorporating elements of social anxiety.

In contrast, narcissistic personality disorder, which falls under cluster B, is marked by a pervasive pattern of grandiosity, a need for admiration, and a lack of empathy. It features distinctive traits such as an inflated sense of self-importance and preoccupation with fantasies of success. This difference in characteristics and behaviors clearly separates narcissistic personality disorder from the disorders included in cluster A.