Validation of schizoid personality scales using indices of schizotypal and borderline personality disorder in a criminal population.

The external validity of 10 schizoid personality scales was assessed against dimensional measures of DSM-III borderline (BPD) and schizotypal (SPD) personality disorders in a sample of 37 top-security prisoners. Significant relationships with SPD or BPD emerged for schizophrenism, withdrawn-disturbed relationships, hallucinatory predisposition, schizoidia, disordered thinking and perceptual aberration (r = 0.30-0.66). The first four of these scales were significantly related to SPD (r = 0.29-0.51) after partialling out the effects of BPD, indicating an intrinsic link between these scales and SPD which may constitute the genetic affinity of SPD with schizophrenia. It is suggested that scales which assess the construct of schizophrenism or 'interpersonal aversiveness' may be the most central to Meehl's (1962) 'integrative neural defect' or genetic predisposition to schizotypy.