Figure 2.

Study waves and assessments. The chart illustrates the overall design of the study, and included six assessment waves over 30 years (columns) and three generations (rows). The original probands (Generation 1) were selected either from specialty clinics for the treatment of mood disorders (depressed probands) or from the community in the same geographical area (non-depressed probands). These probands were then followed longitudinally over time, along with their children (Generation 2) and, beginning with the third wave, grandchildren (Generation 3). Clinical assessment procedures, in blue, included a full diagnostic interview based on the age-appropriate version of the schedule for affective disorders and schizophrenia, as well as a battery of clinical, behavioural and family environmental assessments, as outlined in the text. Beginning with the fourth wave, biological measures (shown in green) were introduced into the study. Electroencephalographic recordings were included in the fourth, and structural and functional MRI assessments and DNA collection, in the fifth, waves. In the sixth wave of the study, which is ongoing, all three measures are being recollected.