This paper compares results of two separate published studies regarding adolescent males with conduct disorders and/or personality disorders/traits. Both studies were published in Behavior Analyst Today, Vol. 3, No. 4, Vol 5, No. 1, respectively. The concept is to evaluate two treatment research studies that represent the best practices for each intervention. The first paper in this comparison represented a group of 10 adolescents, treated with a manual-based cognitive behavior therapy (CBT) called Thought Change. The results of study were promising at time of publication. The second paper was a group of 10 adolescent males at same residential treatment center. There was one therapist who was involved in treatment in both studies, first author of this paper. The second paper used mode deactivation therapy (MDT) (Apsche, Ward, & Evile 2001; Apsche & Ward 2002). Although both papers produced promising results, potential usefulness of comparison in current paper is to examine what intervention might hold more promise for this typology of adolescents. Keywords: Mode Deactivation Therapy; Cognitive Behavior Therapy; Thought change; Best practices; Adolescents with conduct and/or personality disorders. ********** Examining comparative data between two published studies, one CBT and other MDT as a CBT was interesting for many reasons. Both studies were conducted at same facility, a residential sex offender program for adolescent males and had first author of this paper as one of therapists. The CBT study was completed first. Thought Change, CBT methodology, was an effort to establish an effective manual-based treatment to address complexities of adolescent male sexual offender's. MDT was developed to address more reactive adolescents who were not successful in regular CBT. The MDT individuals did not or could not complete Thought Change (CBT) program and needed methodology to be adjusted for their extreme dichotomous, emotional dysregulation and reactive aggression. Cognitive Behavioral Therapy (CBT) Thought Change (TC) as a CBT methodology was designed to treat a conglomerate of personality disorders. The treatment of higher risk, aggressive sex offender focuses on specific deviant sexual arousal and antisocial sub-structure. For same-sex offender of young children who continues to show deviant interest in young victims, Thought Change addresses specific indices of this sub-group. Thought Change explores deficits in self-esteem, social competency, and frequent depression. Many of these youths display severe personality disorders with psychosexual disturbances and high levels of aggression and violence; therefore, Thought Change also focuses on specific individual indices of these issues by identifying and modifying complex system of beliefs. The Thought Change curriculum consists of a structured treatment program, which addresses dysfunctional beliefs that drive sex offending behaviors. Topics in Thought Change curriculum include following: Daily Record of Negative Thoughts, Cognitive Distortions, Changing Your Thoughts, Sexual Offense System, System of Aggression and Violence for Sex Offenders, Moods (how to change them), Beliefs (how it all fits together), Responsibility, Health Behavior Continuum, Beliefs and Substance Abuse, Beliefs and Empathy, The Beliefs of Victim/Offender, The Victim/Victimizer, and Mental Health Medication System. The sections of Thought Change Workbook are designed to progress sequentially through therapy. It is a record of dysfunctional beliefs prior to, during, and following sexual offense. Mode Deactivation Therapy (MDT) as a Cognitive Behavioral Therapy (CBT) The focus of MDT is based on work of Aaron Beck, M.D., particularly his recent theoretical work, system of modes (Beck, 1996, Alford & Beck, 1997). …