In criminological practice, it has been needed to develop some sort of screening tests to differenciate personality disorders or psychopath. We, therefore, attempted to compare the results of two psychological tests in psychopathic delinquents group (PD) with those in non-personality-disorder delinquents group (ND), and to establish objective and practical standards for differenciating the psychopath in connection with the treatment.
The multiple correlation ratio method was applied to analizing 13 scale scores of the Ministry of Justice Personality Inventory (MJPI) and 11 categories relevant to psychopathic syndromes from the Ministry of Justice Sentence Completion Test: Form Youth-I (SCT). According to this method, structure coefficients and weight coefficients were calculated. The psychopathic scale scores for each of subjects were also calculated by using these weight coefficients.
126 subjects (PD:88, ND:38) for the MJPI, and 131 subjects (PD:49, ND:82) for the SCT were selected from among the sample of the previous study, “A Study on the Diagnosis of Psychopathic Juvenile Delinquents.” (1973)
Among structure coefficients of 13 scale scores of the MJPI, those of Paranoid (P), Depression (D), Deviation (De), Unstable (U), and Explosion (X) were found to be significant. Throughout some discussions on psychological meanings of these 5 scales, it was concluded that these were at least related to emotional unstability.
Weight coefficients of P and D were also found to be higher than those of another scales. Although weight coefficients were not always concerned directly with the psychopathic scale, it could be taken for granted that P and D, representative of paranoid trends, anxiety trends respectively, were fundamental factors in differenciating the psychopath.
The means and standard deviations of the psychopathic scale scores with the MJPI were 0.43, 0.82 for PD, and -0.99, 0.58 for ND, respectively. The multiple correlation ratio was so high (r=0.65) that the psychopathic scale might be put to practical use.
As for the SCT, the categories indicating high plus structure coefficients were “lack of emotionality and/or bad human relations”, “lack of durability”, “unstability or immaturity of emotion” and “ignorance of social norms and/or group norms”. On the other hand, the categories indicating minus structure coefficients were “persistency” and “erasing and/or omitting letters”. Moreover, the response frequencies in these categories were found to be almost same for both groups.
In most categories, weight coefficients ran parallel to structure coefficients. But, “lack of guilt feelings and/or inability to profit by or to use experience” showed minus score in weight coefficient, although it showed plus score in structure coefficient.
The means and standard deviations of the psychopathic scale scores with the SCT were 0.85, 0.83 for PD, and -0.51, 0,69 for ND, respectively. In addition, the multiple correlation ratio was fairly high (r=0.61). These results indicated that there was a significant difference between PD and ND, as it was showen for the MJPI.
