An evaluation of the Minnesota Multiphasic Personality Inventory as a discriminator of primary organic and primary psychogenic impotence in diabetic males.

The ability of the MMPI to discriminate between primary psychogenic impotence and primary organic impotence in males with diabetes mellitus was assessed. In order to provide the MMPI with the optimal situation to discriminate between the two groups, we attempted to form a homogeneous sample in terms of physical conditions. Thirty impotent diabetic males were classified as primary organic or primary psychogenic based on nocturnal penile tumescence data. Beutler et al.'s MMPI decision rules yielded a 63% misclassification of the two groups. Possible explanations for the lack of discriminative power of the MMPI with this sample of diabetic males were discussed in relation to previous findings. The power of nocturnal penile tumescence to classify men as having primary organic or primary psychogenic impotence was examined with reference to other vascular and endocrine variables.