The psychopathology and particularly the personality disorders of sex offenders were compared to general inmates of the Colorado Department of Corrections. Using the MCMI-III (Millon, 1994, 1997), sex offenders in general were found to have more varied types of personalities than general population inmates. Specifically, they were more schizoid, avoidant, depressive, dependent, self-defeating, and schizotypal. General population inmates had the more classically criminal personality characteristics of antisocial, narcissistic, and sadistic. Multivariate analysis showed the Dependent, Narcissistic, Antisocial, and Schizotypal scales to be the most differentiating. Sex offenders were also found to have more affective psychopathology such as anxiety, dysthymia, PTSD, and major depression. A similar trend was found when comparing child molesters to rapists. The child molesters were more neurotic, affective, and socially impaired than the rapists. Multivariate analysis showed the Dependent scale to be the most important in differentiating these two types of sex offenders.

The Millon Clinical Multiaxial Inventory-III (MCMI-III) is well suited for use in corrections settings. The MCMI-III's scales correlate with the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV) personality disorders (frequently found in correctional settings), and the publisher offers a corrections-specific interpretive package. To further elucidate the usefulness of the MCMI-III with offenders and assess its efficacy, the authors administered the test to more than 10,000 inmates of the Colorado Department of Corrections. Scale scores were compared to intake judgment and outcome variables across mental health, substance abuse, and violence variables. A number of scales were found to predict several mental health variables such as subsequent diagnosis, medication prescription, and therapy time. Substance abuse scale elevations corresponded to subsequent intake recommendations. Although more modest, the aggressive personality disorder scales and several of the neurotic scales correlated with future institutional violence. The authors discuss the relevance of these findings to screening, triage, and correctional assessment.