The Netherlands Study of Depression and Anxiety (NESDA, www.nesda.nl) is an ongoing study to: 1) describe the long-term course and consequences of depressive and anxiety disorders, and 2) to examine the demographic, psychosocial, somatic, biological and genetic determinants of this course. This presentation describes NESDA's rationale, sampling frame and methods.

The design is an 8-year longitudinal cohort study following 2,850 participants aged 18 through 65 years. The sample consists of 1600 persons with a current (6 month recency) diagnosis of depression or anxiety disorder, 850 persons at risk (because of high symptomatology, family or life-time history), and 400 healthy controls. Recruitment takes place in the community, through 65 general practitioners (using a three-stage screening procedure), and through 17 mental health care institutions in order to include patients reflecting various settings and stages of psychopathology. The 4-hour baseline assessment includes questionnaires, interviews, a medical exam, a computer task and blood (including DNA and RNA) and saliva collections. Follow-up assessments are repeated after 1, 2, 4 and 8 years.

Over 2500 respondents with more than 2100 current diagnoses of depression or anxiety disorders, were recruited in November 2006 (mean age = 41 years, 67% female). Expected end date of recruitment is in February 2007.

NESDA is expected to provide more insight into (predictors of) the course of affective disorders. NESDA is open for collaboration (including data utilization) with other European research groups, which we hope to stimulate by a presentation of its design and methods.