title: Association of PER2 genotype and stressful life events with alcohol drinking in young adults.
abstract: BACKGROUND
  Clock genes govern circadian rhythms and shape the effect of alcohol use on the physiological system. Exposure to severe negative life events is related to both heavy drinking and disturbed circadian rhythmicity. The aim of this study was 1) to extend previous findings suggesting an association of a haplotype tagging single nucleotide polymorphism of PER2 gene with drinking patterns, and 2) to examine a possible role for an interaction of this gene with life stress in hazardous drinking.
  
  
  METHODS
  Data were collected as part of an epidemiological cohort study on the outcome of early risk factors followed since birth. At age 19 years, 268 young adults (126 males, 142 females) were genotyped for PER2 rs56013859 and were administered a 45-day alcohol timeline follow-back interview and the Alcohol Use Disorders Identification Test (AUDIT). Life stress was assessed as the number of severe negative life events during the past four years reported in a questionnaire and validated by interview.
  
  
  RESULTS
  Individuals with the minor G allele of rs56013859 were found to be less engaged in alcohol use, drinking at only 72% of the days compared to homozygotes for the major A allele. Moreover, among regular drinkers, a gene x environment interaction emerged (p = .020). While no effects of genotype appeared under conditions of low stress, carriers of the G allele exhibited less hazardous drinking than those homozygous for the A allele when exposed to high stress.
  
  
  CONCLUSIONS
  These findings may suggest a role of the circadian rhythm gene PER2 in both the drinking patterns of young adults and in moderating the impact of severe life stress on hazardous drinking in experienced alcohol users. However, in light of the likely burden of multiple tests, the nature of the measures used and the nominal evidence of interaction, replication is needed before drawing firm conclusions.
authors.affiliation: Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Dorothea
authors.initials: D
authors.lastname: Blomeyer
authors.forename: Arlette F
authors.initials: AF
authors.lastname: Buchmann
authors.forename: Jesus
authors.initials: J
authors.lastname: Lascorz
authors.forename: Ulrich S
authors.initials: US
authors.lastname: Zimmermann
authors.forename: Günter
authors.initials: G
authors.lastname: Esser
authors.forename: Sylvane
authors.initials: S
authors.lastname: Desrivieres
authors.forename: Martin H
authors.initials: MH
authors.lastname: Schmidt
authors.forename: Tobias
authors.initials: T
authors.lastname: Banaschewski
authors.forename: Gunter
authors.initials: G
authors.lastname: Schumann
authors.forename: Manfred
authors.initials: M
authors.lastname: Laucht
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000235:genetics*; D015331:Cohort Studies; D005260:Female; D005838:Genotype; D006801:Humans; D008016:Life Change Events; D008297:Male; D056950:Period Circadian Proteins / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012307:Risk Factors; D013315:Stress, Psychological / Q000235:genetics*; D055815:Young Adult
chemical_list: C421902:PER2 protein, human; D056950:Period Circadian Proteins