Early developmental stages of psychopathology study (EDSP): objectives and design.

The primary and secondary objectives of the Early Developmental Stages of Substance Abuse Study (EDSP) are described along with a detailed description of the overall design, special design features and instruments used. The EDSP is a 5-year prospective study with three waves of assessments. Special design features are the linkages with family genetic investigations as well as neuroendocrinological stress tests in high-risk subjects. Overall, 3,021 adolescents and young adults aged 14-24 years are included. The response rate for the baseline investigation was 71%. Diagnostic assessments were made by using a modified lifetime (baseline) and 12-month change version of the WHO-CIDI, adjusted for DSM-IV. Modifications refer to a more detailed quantitative assessment of symptoms and substance use variables as well as the inclusion of questions to assess course of disorders and subthreshold diagnostic conditions.