Dextro-Amphetamine Versus Caffeine in Treatment-resistant OCD

Inclusion Criteria: * outpatient age 18 through 55 inclusive * meets DSM-IV criteria for obsessive-compulsive disorder (OCD) with Yale-Brown Obsessive-Compulsive Scale (YBOCS) score greater than or equal to 20 * provides written informed consent * has taken for at least 12 weeks at least the dose shown of a selective serotonin reuptake inhibitor (SSRI) \[citalopram, escitalopram, or fluoxetine 20 mg/d; paroxetine 40 mg/d; sertraline 50 mg/d\]; or venlafaxine 225 mg/d; or duloxetine 60 mg/d. * if taking buspar, gabapentin, an atypical antipsychotic, or a benzodiazepine, dose has been stable for 4 weeks * has negative urine drug and pregnancy tests * is practicing reliable birth control method * has blood pressure readings at screening visit that are less than 140 mm Hg systolic and 90 mm Hg diastolic, * weight is greater than 100 lbs at screen Exclusion criteria: * requires psychotropic medications other than an Serotonin Reuptake Inhibitor (SRI), a benzodiazepine, buspirone, an atypical antipsychotic, and/or gabapentin * is taking clomipramine * is taking fluvoxamine * is taking medication that inhibits hepatic enzyme CYP1A2 * is taking a monoamine oxidase inhibitor * has co-morbid tics or Tourette's disorder * has hoarding as the primary or only OCD symptom * has a history of panic disorder * has a history of glaucoma * has a history of seizures * has a history of schizophrenia or psychotic disorder, or schizotypal personality disorder * has depression with current suicide risk * has mental retardation, pervasive developmental disorder, or cognitive disorder * has a factitious disorder * has current or past cyclothymic disorder or bipolar disorder * has a dissociative disorder * has personality disorder sufficient to interfere with study participation * has organic mental disorder or dementia * has current or past substance abuse / dependence (excluding nicotine) * has current or past anorexia or bulimia * has serious or unstable medical disorder, including hypertension or cardiac disease * has history of myocardial infarction or cardiac arrhythmia * has history of or has current diagnosis of hypertension * is pregnant or breast-feeding * is receiving psychotherapy for OCD * is intending to receive psychotherapy for OCD during the study * has had a previous trial of d-amphetamine of at least 30 days duration * is unable to speak, read, or understand English * is not likely to follow study procedures * is not suitable for study in the investigator's opinion