Surveys.60,122 Third, the NIMH took advantage of the opportunity to collect nationally representative data on adolescent mental health by extending the lower age range of the National Comorbidity Survey Replication (NCS-R),123 a nationally representative survey of adult mental disorders that was fielded from 2001 to 2003. The decision was made to limit the sample to youth ages 13 to 17 because pilot studies showed that the interview schedule used in the NCS-R, the WHO Composite International Diagnostic Interview (CIDI) Version 3.0,123 had limited validity among youth younger than age 13. This NCS-R Adolescent Supplement (NCS- A) was consequently carried out in a nationally representative sample of 10 148 youth in the age range of 13 to 17.
