2. We propose to use a transdiagnostic approach where participants will be stratified according to their symptom severity to have a full representation of different depressive severities and components of the depressive phenotype in the cohort. To ensure recruitment of participants from each level of this phenotype, we will employ a stratified sampling approach to recruit 12 participants who are asymptomatic (i.e., Montgomery-Asberg Depression Rating Scale (MADRS) score=0-6); 12 who are mildly symptomatic (i.e., MADRS score=7-19; 12 who are moderately symptomatic (i.e., MADRS sore=20-34); and 12 who are severely symptomatic (i.e., MADRS score>34).