This case study is to evaluate the effectiveness of Mode Deactivation Therapy (MDT) implementation in a child and adolescent residential treatment unit and provide preliminary effectiveness data on MDT versus treatment as usual (TAU). This case study compared the efficacy of two treatment methodologies for adolescent males in residential treatment with conduct disorders and/or personality dysfunctions with physically or sexually aggressive behaviors over one year. The twenty patients were admitted to the same residential treatment unit, ten were given the MDT protocol and the other relied on TAU. Assessments of depressive symptoms, suicidal ideation, along with monitoring of aggressive behaviors with the evaluations conducted after one year of treatment. The results showed MDT to be more effective then TAU in reducing both physical aggression and therapeutic restraints. The promising results of this study suggest that further evaluation of MDT for the treatment of adolescent's residential patients is warranted. (Contains 8 figures and 6 tables.)