The BP cases were interviewed using established diagnostic instruments and diagnosed with bipolar disorder according to the RDC (Research Diagnostic Criteria) (31), DSMIII-R (Diagnostic and Statistical Manual of Mental Disorders) DSM-IV or ICD-10. Diagnostic instruments used were the SCID (Structured Clinical Interview for DSM disorders) (32), the SADS-L (Schedule of Affective Disorders and Schizophrenia-Lifetime version) (33), the DIGS (Diagnostic Instrument for Genetic Studies) (34), the MINI (Miniinternational Neuropsychiatric Interview) (35), the ADE (Affective Disorders Evaluation) (36) and the SCAN (Schedules for Clinical Assessment in Neuropsychiatry) (37). Data from these interviews was combined with information from case notes and in some cases supplemented with data from the OPCRIT (operational criteria checklist for psychotic illness) (25). A full description of the instruments used in each of the collaborating centers is given in the supplementary data that accompanied the PGC bipolar disorder meta-analysis (38). We considered subjects experiencing hallucinations or delusions during a manic or depressive episode to have Bipolar Disorder with Psychotic Features.
