Cluster A personality disorders are characterized by odd or eccentric behaviors. The primary disorders in this cluster include:

Paranoid Personality Disorder
This disorder is defined by a pervasive pattern of distrust and suspiciousness of others, beginning in early adulthood and present in a variety of contexts. Individuals with this disorder tend to interpret the motives of others as malevolent. Salient features include:
* Unjustified belief that others are exploiting, harming, or deceiving them.
* Reluctance to confide in others due to fear that information will be used maliciously against them.
* Reading hidden demeaning or threatening meanings into benign remarks or events.
* A persistent tendency to bear grudges.
* Recurrent, unjustified suspicions regarding the fidelity of a spouse or sexual partner.

Schizoid Personality Disorder
This disorder is characterized by a pervasive pattern of detachment from social relationships and a restricted range of emotional expression in interpersonal settings. Individuals with this disorder typically:
* Almost always choose solitary activities.
* Lack close friends or confidants other than first-degree relatives.
* Appear emotionally cold, detached, and exhibit a flattened affectivity.

Schizotypal Personality Disorder
This disorder is a pervasive pattern of social and interpersonal deficits marked by acute discomfort with, and reduced capacity for, close relationships, as well as cognitive or perceptual distortions and eccentricities of behavior. Its prominent features include:
* Odd or eccentric patterns of thinking and speech (e.g., vague, circumstantial, overly elaborate, or stereotyped).
* Inappropriate or constricted affect (emotional responses).