Which of the following is a defining trait of schizoid personality disorder?

A defining trait of schizoid personality disorder is social withdrawal. Individuals with this disorder often exhibit a pervasive pattern of detachment from social relationships and a limited range of emotional expression in interpersonal settings. They may prefer solitary activities and rarely seek out or enjoy close relationships, including those with family members. This withdrawal is not simply a preference for solitude, but a significant aspect of their personality that influences their interactions and overall functioning in social contexts.

The other options present characteristics that do not align with schizoid personality disorder. Overactive emotional expression is contrary to the emotional blunting typically seen in individuals with this disorder. Strong interpersonal connections are also not characteristic, as those with schizoid personality disorder often lack the desire for such connections. Finally, assumptions of superior intellect could suggest traits more commonly associated with narcissistic personality traits rather than the emotional detachment and lack of social engagement central to schizoid personality disorder.