In Reply Our study showed that, among individuals with severe mental illness, the rates of tobacco, alcohol, and other substance use are dramatically higher than in the general population.1 The criticisms made by Knapp and Hayat highlight long-standing statistical controversies: effect size vs P value and proper adjustment for confounding variables.
Article InformationCorresponding Author: Sarah M. Hartz, MD, PhD, Department of Psychiatry, Washington University in St Louis, 660 S Euclid Ave, Campus Box 8134, St Louis, MO 63110 (email@example.com).
Conflict of Interest Disclosures: Dr Bierut is listed as an inventor on issued US patent 8,080,371, “Markers for Addiction,” covering the use of certain single-nucleotide polymorphisms in determining the diagnosis, prognosis, and treatment of addiction. No other disclosures were reported.
Funding/Support: This project was funded by National Institutes of Health grants U10 AA008401, UL1 RR024992, P01 CA089392, R01 MH085548, R01 MH085542, K08 DA062380-1, KL2 RR024994, and K01 DA025733 and American Cancer Society grant ACS IRG-58-010-54.
Role of the Sponsor: The funders had no role in the preparation, review, or approval of the manuscript, and the decision to submit the manuscript for publication.
Additional Information: This letter represents the views of the coauthors on the original manuscript including Carlos N. Pato, MD, PhD, Patricia Cavazos-Rehg, PhD, and Janet L. Sobell, PhD.