The Blue Sky Project, a 5-year study funded by the Canadian Institutes of Health Research, seeks to examine how genetics and early life experiences work together to cause a person's very first onset of depression by increasing sensitivity to stress.

Many forms of stress can precipitate an episode of depression. However, not everyone who experiences these sorts of stressors becomes depressed. Individuals with an at-risk genetic profile are more likely to get depressed in the face of stress, and require less severe levels of stress to get depressed, than individuals without this genetic profile. This model can help explain why young people get depressed the very first time. Young people with a particular variant of the serotonin transporter gene might require less severe levels of stress in both childhood and adulthood to precipitate their first episode of depression than individuals who do not possess this at-risk genetic variant. The current study involves 3 arms:

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.

Participant at the Sunnybrook Health Sciences Centre site were enrolled in an assessment-only non-treatment arm. A research assistant met with participants to complete the same standard psychological tests as above. Participants received standard medical care from their attending psychiatrist. Participants may continue into the follow-up phase involving short appointments over an 18-month period to complete psychological assessments. This arm of the study has finished and is no longer recruiting participants.

Participant at the Queen's University site are enrolled in an assessment-only non-treatment arm. A research assistant will meet with participants to complete the same standard psychological tests as above. Participants will receive standard medical care from their attending psychiatrist or will be referred for treatment if they do not currently have a psychiatrist. Participants may continue into the follow-up phase involving short appointments over an 18-month period to complete psychological assessments.

Inclusion Criteria:

• Current diagnosis of non-psychotic unipolar major depression; first onset
• Between 16 and 29 years of age
• Free of antidepressant treatment for a minimum of two weeks prior to treatment OR on an inadequate antidepressant treatment
• Minimum 8th grade education and fluency in reading English
• Live in the Kingston Area; willing to travel to the Queen's University for appointments

Exclusion Criteria:

• Diagnosis of previous episode(s) of major depression
• Past or present diagnosis of Bipolar Disorder, Schizoaffective Disorder, Schizophrenia, Substance Dependence Disorder, Borderline Personality Disorder, Anti-social Personality Disorder, or Organic Brain Syndrome
• Electroconvulsive Therapy in the past 6 months
• Concurrent serious medical illness judged to be contributing to the depression or impacting on treatment
• Presence of significant suicidal ideation