Which personality disorder is characterized by extreme suspiciousness or mistrust of others?

Paranoid personality disorder is characterized by a pervasive and unjustified mistrust and suspicion of others. Individuals with this disorder often interpret the actions of others as malevolent, even when there is no evidence to support such beliefs. This extreme level of distrust can lead to significant difficulties in relationships and social situations, as individuals may become isolated due to their fears and suspicions of betrayal or harm.

In the context of other personality disorders listed, borderline personality disorder involves emotional instability and intense interpersonal relationships rather than a predominant theme of suspicion. Antisocial personality disorder is characterized by a disregard for the rights of others and lack of empathy, often resulting in manipulative or harmful behaviors. Avoidant personality disorder, on the other hand, features a pattern of social inhibition and feelings of inadequacy, with a strong desire for social acceptance, rather than suspicion.

The distinctiveness of paranoid personality disorder lies in its focus on suspicion and mistrust, making it the accurate choice for the given question.