There are 2 parts to this study: In Part 1, patients are placed into 1 of 2 groups based on type of OCD, determined by medical history and family member interviews. In Part 2, patients are treated with fluvoxamine (FVX) for 8 weeks. If patients do not respond to FVX alone, either haloperidol or an inactive placebo will be added to the FVX regimen; patients will take this drug combination for 4 weeks. Patients will be monitored throughout the trial.