Which personality disorder involves significant mistrust of others?

Paranoid personality disorder is characterized by a pervasive and enduring pattern of distrust and suspicion toward others. Individuals with this disorder often believe that others are out to harm or deceive them, even when there is little or no evidence to support these beliefs. This significant mistrust can lead to difficulties in forming and maintaining relationships, as those affected may interpret benign remarks as hostile or threatening.

The focus on mistrust as a central feature of paranoid personality disorder sets it apart from the other disorders listed. For instance, schizoid personality disorder involves a lack of interest in social relationships and a preference for solitude, while avoidant personality disorder is characterized by feelings of inadequacy and hypersensitivity to negative evaluation but does not primarily center on mistrust. Narcissistic personality disorder involves a grandiose sense of self-importance and a need for admiration, often disregarding others' feelings without the prominent element of mistrust present in paranoia. Therefore, the defining feature of paranoia within paranoid personality disorder makes it the correct choice.