Mischa Barton Says She Couldn't Escape Abusive Sex Tape Partner

Mischa Barton is ripping the ex-bf behind the sex tape that's being shopped around, and says he's more interested in destroying her emotionally than financially.

Mischa went on 'Dr. Phil' and revealed the exact moment she found out about the tape. As she's said ... the guy responsible is someone she used to love, but she told Phil she desperately tried to distance herself from him after finding out about the secret recording. It didn't work.

The episode airs Monday, and Mischa will also talk about that bizarre incident in her backyard, where she claimed she was slipped "a cocktail of drugs."