NCAM1-TTC12-ANKK1-DRD2 variants and smoking motives as intermediate phenotypes for nicotine dependence

• Published in: Psychopharmacology 2015-04, Vol.232 (7), p.1177-1186
• Main Authors: Bidwell, L. C., McGeary, J. E., Gray, J. C., Palmer, R. H. C., Knopik, V. S., MacKillop, J.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Biomedical and Life Sciences; Biomedicine; CD56 Antigen - genetics; Diagnosis; Dopamine; Female; Genetic aspects; Genetic Variation - genetics; Genotype & phenotype; Haplotypes; Health aspects; Humans; Male; Motivation - genetics; Neurosciences; Nicotine; Original Investigation; Pharmacology/Toxicology; Phenotype; Phenotypes; Polymorphism; Polymorphism, Single Nucleotide - genetics; Protein Serine-Threonine Kinases - genetics; Proteins - genetics; Psychiatry; Psychopharmacology; Receptors, Dopamine D2 - genetics; Smoking - epidemiology; Smoking - genetics; Tobacco habit; Tobacco Use Disorder - diagnosis; Tobacco Use Disorder - epidemiology; Tobacco Use Disorder - genetics; White People - genetics; Young Adult
• ISSN: 0033-3158; 1432-2072
• DOI: 10.1007/s00213-014-3748-2

Rationale Nicotine dependence (ND) is a heterogeneous phenotype with complex genetic influences. The use of intermediate ND phenotypes may clarify genetic influences and reveal specific etiological pathways. Prior work has found that the four Primary Dependence Motives (PDM) subscales (Automaticity, Craving, Loss of Control, and Tolerance) of the Wisconsin Inventory of Smoking Motives (WISDM) represent heavy, pervasive smoking, which is a core feature of nicotine dependence, making these motives strong candidates as intermediate phenotypes. Objective This study examines the WISDM PDM as a novel intermediate phenotype of nicotine dependence. Methods The study used data from 734 European Americans who smoked at least 5 cigs/day [ M  = 16.2 ( SD  = 9.5) cigs/day], completed a phenotypic assessment, and provided a sample of DNA. Based on prior evidence of the role of genetic variation in the NCAM1-TTC12-ANKK1-DRD2 region on chromosome 11q23 in smoking behavior, associations among 12 region loci with nicotine dependence and PDM phenotypes were examined using haplotype and individual loci approaches. In addition, mediational analysis tested the indirect pathway from genetic variation to smoking motives to nicotine dependence. Results NCAM1-TTC12-ANKK1-DRD2 region loci and haplotypes were significantly associated with the motive of Automaticity and, further, Automaticity significantly mediated associations among NCAM1-TTC12-ANKK1-DRD2 cluster variants and nicotine dependence. Conclusions These results suggest that motives related to automaticity are a viable intermediate phenotype for understanding genetic contributions to nicotine dependence. Further, NCAM1-TTC12-ANKK1-DRD2 variants may increase the likelihood that a person will become dependent via a highly automatic smoking ritual that can be elicited with little awareness.