title: Examining the heritability of a laboratory-based smoking endophenotype: initial results from an experimental twin study.
abstract: The objective of this study was to examine the heritability of an endophenotype relevant to nicotine dependence, namely tension reduction after smoking. This study also examined whether common genetic, shared environmental, and nonshared environmental factors influence this endophenotype measured repeatedly during an experimental paradigm. Twin and sibling pairs, all of whom were regular smokers, completed a laboratory paradigm in which they reported on levels of tension at baseline and after smoking each of 3 cigarettes. Univariate twin analyses suggested a sizeable role of additive genetic effects on tension reduction, with heritability estimates ranging between 47 and 68%. Result of multivariate Cholesky analyses indicated that there were additive genetic influences common to tension reduction assessed after cigarettes 1, 2, and 3. Multivariate models including genetic and nonshared environmental effects provided the best fit to the data. To the best of our knowledge, this is the first study to examine the genetic basis of a laboratory smoking endophenotype, in this case tension reduction after smoking. Implications for genetic association studies are discussed.
authors: Department of Psychology and Institute for Behavioral Genetics, University of Colorado, Boulder, Colorado, United States of America. lara_ray@brown.edu
authors: Lara A
authors: LA
authors: Ray
authors: Soo Hyun
authors: SH
authors: Rhee
authors: Michael C
authors: MC
authors: Stallings
authors: Valerie
authors: V
authors: Knopik
authors: Kent E
authors: KE
authors: Hutchison
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D035781:Siblings; D012907:Smoking / Q000235:genetics* / Q000523:psychology*; D013315:Stress, Psychological / Q000235:genetics* / Q000523:psychology; D014029:Tobacco Use Disorder / Q000235:genetics* / Q000523:psychology*; D014429:Twins, Dizygotic / Q000235:genetics / Q000523:psychology; D014430:Twins, Monozygotic / Q000235:genetics / Q000523:psychology