title: Alcohol dependence in men: reliability and heritability.
abstract: BACKGROUND
  The assessment of a Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) life-time history of alcohol dependence (LTH-AD) has been found to be moderately reliable and substantially heritable. However, in studies of the heritability of LTH-AD, measurement error could not be discriminated from the true unique environmental effects. The aims of this study were to: (i) estimate the reliability of LTH-AD in a population based sample, (ii) identify characteristics of LTH-AD predicting a reliable diagnosis, (iii) investigate the heritability of LTH-AD as a function of diagnostic confidence, and (iv) to estimate the genetic and environmental influences on LTH-AD correcting for measurement error.
  
  
  METHODS
  An unselected sample of 4,203 male twins was interviewed twice approximately 1-year apart assessing DSM-IV LTH-AD over the same period of life. Logistic regression was used to identify clinical features that predict a reliable diagnosis LTH-AD. Genetic and environmental influences on reliable LTH-AD were examined using structural equation models.
  
  
  RESULTS
  Reliability of the diagnosis of LTH-AD was moderate (κ = 0.54) and was predicted by the number of AD symptoms, treatment seeking, duration of most severe episode, and a great deal of time spent to obtain, use, or recover from alcohol use (DSM-IV AD criterion #5). Using an index of caseness, heritability of LTH-AD increased as a function of diagnostic confidence. Accounting for errors of measurement in a multivariate twin model, the heritability of LTH-AD increased from 55 to 71%.
  
  
  CONCLUSIONS
  Reliably diagnosed LTH-AD can be predicted by characteristics relevant to the disorder. LTH-AD appears to be a moderately reliable disorder of high heritability.
authors.affiliation: Department of Adult Mental Health, Norwegian Institute of Public Health, Oslo, Norway. eivind.ystrom@fhi.no
authors.forename: Eivind
authors.initials: E
authors.lastname: Ystrom
authors.forename: Ted
authors.initials: T
authors.lastname: Reichborn-Kjennerud
authors.forename: Steven H
authors.initials: SH
authors.lastname: Aggen
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Kendler
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000175:diagnosis* / Q000453:epidemiology* / Q000235:genetics; D016208:Databases, Factual; D004200:Diseases in Twins / Q000175:diagnosis*; D004522:Educational Status; D006801:Humans; D007406:Interview, Psychological; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D011569:Psychiatric Status Rating Scales; D015203:Reproducibility of Results; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult