Study Search Results Your query returned 3 results. Series results are grouped under the most relevant study. You can ungroup series results. Use the search box below to revise your search, or start a new search. Results per page: 25 50 100 Sort by: Study Relevance Title A-Z Released/Updated Time Period Most Cited in ICPSR Bib. Most Downloaded Variable Relevance (?) Study Title/Investigator 1. National Comorbidity Survey: Baseline (NCS-1), 1990-1992 (Restricted Version) (ICPSR 25381) Kessler, Ronald C. 2. National Comorbidity Survey: Reinterview (NCS-2), 2001-2002 [Restricted-Use] (ICPSR 30921) Kessler, Ronald 3. Helping Young Smokers Quit: Identifying Best Practices for Tobacco Cessation, Phase II National Program Evaluation, 2003-2006 (ICPSR 33161) Mermelstein, Robin J.; Curry, Susan J.