there was a dramatic increase in the rates of substance use disorders with age, with a 3-month prevalence rate of 0.3% at age 13,1.4% at age 14,5.3% at age 15, and 7.6% at age 16. Gender differences in prevalence rates of substance use disorders are inconsistent. Whereas several studies show equal prevalence rates in males and females,13 others show that males have greater rates than females.14 Substance use disorders have been generally shown to be more common in white youths, and equally distributed by parental social class.66
