7. Participants must have been in treatment with an SSRI for at least 8 weeks, the last 4 of which were at a dosage of > 20 mg per day of fluoxetine or its equivalent, e.g. 20 mg per day of paroxetine, 20 mg citalopram, 10 mg escitalopram, or 100 mg sertraline. If the participant attempted, but could not tolerate, a dose comparable to 20 mg fluoxetine, they will be considered eligible. (This definition of "Adolescent SSRI Resistant Depression" is modified from the NIH-sponsored, $17 million TORDIA Randomized Controlled Trial [http://clinicaltrials.gov/ct2/show/NCT00018902].