The study design is a two arm randomized clinical trial comparing a one year treatment program of Dialectical Behavior Therapy (DBT) + suboxone for heroin addicted individuals meeting criteria for borderline personality disorder (BPD) to a one year program of standard drug counseling (I/GDC) + suboxone. Drug counseling will consist of manualized individual sessions + group therapy. Participants in both conditions will be prescribed psychotropic medications following a standardized medication protocol developed specifically for BPD individuals. Each site will enroll 86 clients with both treatment conditions being conducted at each site. Assessments measuring drug use, suicidal behaviors, retention and other treatment-related behaviors, general psychopathology and functioning, and increases in behavioral skills will be given at four month intervals for two years