The study was conducted at the Center for Affective
Disorders at the Department of Psychiatry at
St Go¨ ran’s Hospital in Stockholm, the capital of
Sweden. The Center is a specialized out-patient
department for patients with bipolar and unipolar
disorders. It has an inner city catchment area,
where the social class and education levels are
somewhat above average. In the area, general
practitioners and psychiatrists have been instructed
to refer all patients with (or with a history of)
mania or hypomania to the Center duringa period
of at least 20 years.