Analysis of Content Scales of the Minnesota Multiphasic Personality Inventory-2 in Complete and Partial Agenesis of the Corpus Callosum

Agenesis of the corpus callosum (ACC) is a congenital disorder involving complete or partial absence of the corpus callosum. Persons with ACC tend to have social and cognitive deficits that have yet to be sufficiently described. This research used the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) to investigate psychosocial disability in persons with complete and partial ACC. Existing research suggests that persons with ACC tend to manifest a general lack of emotional and interpersonal sophistication in their self-understanding. In this study, there was a significant elevation (relative to the test norms) in scores on the content scale Negative Treatment Indicators. As anticipated, anger was not significantly elevated. In addition to those scales hypothesized to be significantly elevated, elevations in scores on two other content scales---Bizarre Mentations and Cynicism---were found to be statistically significant. Ten content scales were not significantly elevated: Fears, Depression, Obsessiveness, Type A Personality, Low Self Esteem, Health Concerns, Antisocial Practices, Family Problems, Work Interference and Social Discomfort (which was predicted to be significantly elevated). These results highlight the difficulties individuals with ACC have in social interactions and their lack of ability to generate inferences into the mental, emotional and social functioning of others, as well as themselves. There were no significant differences between individuals with complete and partial ACC when controlling for age and IQ. It is possible that the small number of people in each group made significant differences difficult to detect.