Depression and personality disorder: differential diagnosis with the MMPI.

This study assessed the effectiveness of the MMPI in differentiating four clinically relevant types of depression. MMPI profiles of 53 subjects with major depression and personality disorder, 44 subjects with other depression and personality disorder, 27 subjects with major depression without personality disorder, and 20 subjects with other depression without personality disorder were compared via MANOVA, high-point pair analysis, and discriminant analysis. The instrument was found somewhat effective in differentiating the groups at a statistically significant level, but the differences were too subtle to be considered clinically useful. Thus, while the MMPI has some usefulness in the differential diagnosis of depression, it is best used in conjunction with other test data and relevant historical data.