title: Age at first drink relates to behavioral measures of impulsivity: the immediate and delayed memory tasks.
abstract: BACKGROUND
  This study examined the relationship between laboratory-measured impulsivity and age at first drink.
  
  
  METHODS
  Using a laboratory behavioral measure of impulsivity [Immediate (IMT) and Delayed Memory Tasks (DMT)], we compared two groups of women differing in their self-reported age at first drink (early-onset drinking, age <18 years, n = 40; late-onset drinking, age > or =21 years, n = 23). It was expected that those who first consumed alcohol before the legal drinking age (i.e., early onset) would perform in a more impulsive manner on the laboratory behavioral measure than the late-onset drinkers.
  
  
  RESULTS
  The main finding was that the early-onset group (IMT: mean, 28.7%; DMT: mean, 30.4%) had increased commission error rates compared with the late-onset group (IMT: mean, 21.2%; DMT: mean, 15.5%) during both the IMT [ANOVA:F (1,61) = 4.30; p = 0.042; f = 0.27] and DMT [F (1,61) = 10.76; p = 0.002; f = 0.42]. Age at first drink was significantly correlated with DMT commission errors (r = -0.23; p = 0.037), although this was only at the trend level for IMT commission errors (r = -0.20; p = 0.062); these correlations are likely to be underestimates because of range restriction of the age variable.
  
  
  CONCLUSIONS
  These results demonstrate that differences in impulsive behavioral responding are distinguishable even between groups of alcohol drinkers who are not experiencing clinically significant problems with alcohol.
authors.affiliation: University of Texas Health Science Center at Houston, Neurobehavioral Research Laboratory and Clinic, Houston, Texas 77030, USA. donald.m.dougherty@uth.tmc.edu
authors.forename: Donald M
authors.initials: DM
authors.lastname: Dougherty
authors.forename: Charles W
authors.initials: CW
authors.lastname: Mathias
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Tester
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Marsh
mesh_terms: D000328:Adult; D000367:Age Factors; D000428:Alcohol Drinking / Q000523:psychology*; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000523:psychology*; D008568:Memory / Q000502:physiology*; D008570:Memory, Short-Term / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*