Probands with BD were recruited from our ongoing genetic studies.46 The control subjects were either healthy volunteers or married-in relatives of our probands. All study participants underwent diagnostic assessments that followed a strict procedure: after signing an informed consent they were interviewed by pairs of experienced clinician researchers blind to the subject status. The interviews were followed by consensus diagnosis (according to Research Diagnostic Criteria47 and DSM-IV) established by a second blind panel of expert clinical researchers. As the primary diagnostic tool, we used the Schedule for Affective Disorders and Schizophrenia— Lifetime version.48 All interviewers had undergone extensive training previously and established very good inter-rater reliability for both diagnostic49 and treatment response evaluations.50
