Which personality disorder involves detachment from social relationships and restricted affect?

The personality disorder characterized by detachment from social relationships and restricted affect is Schizoid Personality Disorder. Individuals with this disorder typically exhibit a pervasive pattern of social detachment and a limited range of emotional expression in interpersonal situations. They may appear indifferent to social relationships and often prefer solitary activities. This disconnection from others, paired with a lack of desire for intimacy or emotional engagement, reveals the core features of Schizoid Personality Disorder.

While other personality disorders, such as Schizotypal, Paranoid, and Borderline, may have features involving social relationships or emotional expression, none of them encapsulate the specific combination of social detachment and restricted affect exhibited by those with Schizoid Personality Disorder. Schizotypal Personality Disorder reflects eccentric behavior and cognitive distortions, Paranoid Personality Disorder involves pervasive distrust and suspicion of others, and Borderline Personality Disorder is primarily characterized by instability in relationships, self-image, and emotions rather than the clear detachment and restricted affect seen in Schizoid Personality Disorder. Thus, the defining traits of Schizoid Personality Disorder make it the correct answer.