title: A population-based twin study of the genetic and environmental relationship of major depression, regular tobacco use and nicotine dependence.
abstract: BACKGROUND
  Numerous epidemiological studies have reported a positive association between major depression (MD) and regular tobacco use (RU) or nicotine dependence (ND). However, few have used a genetically informative design to assess whether these traits share a common genetic and/or environmental liability.
  
  
  METHODS
  We assessed MD, RU and ND in same-sex twins from the population-based Swedish Twin Registry. In males, we examined both cigarette use and snus (smokeless tobacco) use. We used structural equation modeling to examine the relationship between MD, RU, and ND given RU.
  
  
  RESULTS
  The results suggest modest correlations between MD and RU, and between MD and ND. In males, the liability shared between MD and RU is solely genetic for both cigarettes and snus, while MD and ND share both genetic and unique environmental influences. The continuation to ND given RU differed considerably between cigarette and snus users. In females, both MD-RU and MD-ND relationships are partially attributable to genetic and unique environmental correlations.
  
  
  CONCLUSIONS
  The relationship among MD, RU and ND is at least partially attributable to shared genetic and environmental risk factors. The genetic and environmental correlations between traits are modest. The nature of the shared liability differs by sex, and in males, by the type of tobacco product used. Differences between previous reports and results presented in the current study are suggestive of population differences in how MD and tobacco use inter-relate.
authors.affiliation: Department of Psychiatry, Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, VA 23298-0126, USA. aedwards5@vcu.edu
authors.forename: A C
authors.initials: AC
authors.lastname: Edwards
authors.forename: H H
authors.initials: HH
authors.lastname: Maes
authors.forename: N L
authors.initials: NL
authors.lastname: Pedersen
authors.forename: K S
authors.initials: KS
authors.lastname: Kendler
mesh_terms: D000328:Adult; D003865:Major Depressive Disorder / Q000453:epidemiology* / Q000235:genetics*; D004777:Environment; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D015995:Prevalence; D012307:Risk Factors; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology* / Q000235:genetics*; D013548:Sweden / Q000453:epidemiology; D014029:Tobacco Use Disorder / Q000453:epidemiology* / Q000235:genetics*
references.citation: Addiction. 2008 Dec;103(12):2045-53
references.pmid: 18855807
references.citation: Twin Res. 2002 Oct;5(5):427-32
references.pmid: 12537870
references.citation: Twin Res Hum Genet. 2005 Feb;8(1):60-2
references.pmid: 15836812
references.citation: J Nerv Ment Dis. 2007 May;195(5):369-77
references.pmid: 17502801
references.citation: Pharmacol Biochem Behav. 2000 May;66(1):79-85
references.pmid: 10837846
references.citation: Nicotine Tob Res. 2003 Feb;5(1):77-83
references.pmid: 12745509
references.citation: Am J Epidemiol. 2006 Mar 1;163(5):421-32
references.pmid: 16394201
references.citation: Drug Alcohol Depend. 2009 Sep 1;104(1-2):126-32
references.pmid: 19505773
references.citation: Arch Gen Psychiatry. 2000 Sep;57(9):886-92
references.pmid: 10986552
references.citation: Psychol Med. 1999 Mar;29(2):299-308
references.pmid: 10218922
references.citation: Nicotine Tob Res. 2005 Jun;7(3):343-50
references.pmid: 16085502
references.citation: Am J Psychiatry. 2006 Jan;163(1):109-14
references.pmid: 16390897
references.citation: Am J Psychiatry. 1983 Nov;140(11):1413-25
references.pmid: 6353948
references.citation: Nicotine Tob Res. 2008 Jan;10(1):97-108
references.pmid: 18188750
references.citation: Psychol Med. 2007 May;37(5):705-15
references.pmid: 17181913
references.citation: Arch Gen Psychiatry. 1991 Dec;48(12):1069-74
references.pmid: 1845224
references.citation: Arch Gen Psychiatry. 2002 Dec;59(12):1125-32
references.pmid: 12470129
references.citation: Am J Public Health. 2000 Jul;90(7):1122-7
references.pmid: 10897192
references.citation: Am J Psychiatry. 2003 Apr;160(4):773-9
references.pmid: 12668368
references.citation: J Intern Med. 2002 Sep;252(3):184-205
references.pmid: 12270000
references.citation: Br J Addict. 1991 Sep;86(9):1119-27
references.pmid: 1932883
references.citation: J Pediatr Psychol. 2005 Jun;30(4):319-32
references.pmid: 15863429
references.citation: Eur J Epidemiol. 2003;18(8):745-50
references.pmid: 12974548
references.citation: Health Psychol. 2008 May;27(3S):S207-15
references.pmid: 18979973
references.citation: Arch Gen Psychiatry. 1993 Jan;50(1):36-43
references.pmid: 8422220
references.citation: Addict Behav. 2004 Nov;29(8):1527-39
references.pmid: 15451122
references.citation: Psychol Med. 2004 Oct;34(7):1251-61
references.pmid: 15697051
references.citation: Psychopharmacology (Berl). 2006 Mar;184(3-4):567-76
references.pmid: 16463194
references.citation: Psychol Med. 2004 Oct;34(7):1263-9
references.pmid: 15697052
references.citation: Neuroepidemiology. 2003 Sep-Oct;22(5):275-82
references.pmid: 12902622