difficulty was assessed in terms of both relatively long latency to quit in a community sample and failed abstinence at end of treatment in a treatment trial. Analyses addressed three major questions: 1) Does the natural history of smoking cessation vary by genetic variants in the chromosome 15q25 region? 2) Do these same variants predict cessation in a treatment trial? 3) Does the relation between the genetic variants and cessation depend upon treatment status? The results are relevant to understanding the nature of risk posed by the targeted variants for cessation, and whether the variants have pharmacogenetic implications in treatment assignment or application.
