The Multiphasic Sex Inventory: Diagnosis and prediction of treatment response in child sexual abusers

Abstract

The purpose of this study was to determine the utility of the Multiphasic Sex Inventory (MSI) in predicting treatment progress and therapy outcome of child sexual abuse perpetrators and to examine the diagnostic potential of this instrument for differentiating perpetrator characteristics. The MSI was administered to 122 clients prior to their entry into therapy and again at three month intervals for nine months. No significant changes in MSI scales were found during the nine month period. Retest correlations on the initial test and the first three month retest period ranged from .42 to .84 with an average of .71. Using the initial MSI scores as predictors, the MSI was able to predict between 30% and 47% of treatment variance, depending on what measure was used as a criterion. It was able to differentiate between treatment outcome (success vs. failure) with 70.9% accuracy. The Sexual Assault, Aggravated Assault, Cognitive Distortion/Immaturity, Lie, and Sex Knowledge Scales were the most salient variables in predicting treatment progress and outcome. A factor analysis of the MSI Scales yielded four factors: Assault, Sexual Fantasy, Denial/Dysfunction, and Normal. The Assault Factor accounted for the largest proportion of variance. Results also indicated that the MSI could 1) differentiate among abusers who molest males, females, and both sexes and 2) among abusers who molest only intrafamilial victims, only extrafamilial victims, and those who molest both kinds of victims. The MSI is also an excellent instrument for differentiating between deniers and non-deniers of abuse. The implications of the MSI as an instrument measuring denial is discussed and an MSI profile of a successful therapy candidate is sketched.