Participants at the Centre for Addiction and Mental Health site were enrolled in a 16-week trial of escitalopram (Lexapro/Cipralex), an established SSRI antidepressant that has been shown to be more effective and tolerable than other SSRIs. A psychiatrist and a trained research assistant will meet with participants every 2-3 weeks for the duration of the 16-week trial and participants will be asked to complete a number of standard psychological tests. After completion of the treatment phase, participants may continue into the follow-up phase involving monthly telephone contact and short appointments over an 18-month period. This arm of the study has finished and is no longer recruiting participants.