Differentiation between schizoid and avoidant personalities: an empirical test.

A number of authors have questioned the rationale for subdividing the DSM-II schizoid diagnosis into three separate personality disorders in DSM-III, the schizoid, avoidant, and schizotypal. The present study was designed to explore differences between psychiatric patients with schizoid and avoidant personalities as compared to psychiatric controls with no personality disorder. Differences were examined on demographic data, self-report measures, and clinical information. A Multivariate Analysis of Variance (MANOVA) revealed a significant overall effect for groups across MMPI subscales. However, subsequent univariate Analyses of Variance (ANOVA's) revealed that almost all differences were between the two personality disorder groups as compared to the psychiatric controls. Contrary to expectations, schizoid and avoidant personalities were found to display equivalent levels of anxiety, depression, and psychotic tendencies as compared to psychiatric control patients. No meaningful distinctions were found between the avoidant and the schizoid personalities. Results are discussed in terms of problems with the assessment methods and the diagnostic criteria.