Diagnostic Interview for Genetic Studies (DIGS): inter-rater and test-retest reliability and validity in a Spanish population.

OBJECTIVE To test the reliability and validity of the DIGS in Spanish population. METHODS Inter-rater and test-retest reliability of the Spanish version of DIGS was tested in 95 inpatients and outpatients. The resultant diagnoses were compared with diagnoses obtained by the LEAD (Longitudinal Expert All Data) procedure as "gold standard". The kappa statistic was used to measure concordance between blind inter-raters and between the diagnoses obtained by LEAD procedure and through the DIGS. RESULTS Overall kappa coefficient for inter-rater reliability was 0.956. The kappa value for individual diagnosis varied from major depression=0.877 to schizophrenia=1. Test-retest reliability was 0.926. Kappa for all individual target diagnoses ranged from 0.776 (major depression) to 1. Kappa between LEAD procedure and DIGS ranged from 0.704 (major depression) to 0.825 (bipolar I disorder). CONCLUSION Most of the DSM-IV major psychiatric disorders can be assessed with acceptable to excellent reliability with the Spanish version of the DIGS interview. The Spanish version of DIGS showed an acceptable to excellent concurrent validity. Giving the good reliability and validity of Spanish version of DIGS it should be considered to identify psychiatric phenotypes for genetics studies.