For individuals with incident dependence, the mean age at onset was 34.8 (range = 18 to 87), and the mean number of lifetime AUD symptoms prior to the Wave 1 baseline interview was 3.5 (range = 0 to 30, with rare large symptom counts reflecting individuals who did not satisfy the clustering criterion for the dependence symptoms, i.e., who did not report that some of these symptoms occurred within the same 1-year period) (data not shown). Mean age at onset was higher for individuals who started drinking at ages 18 and older (35.9) than for those who initiated drinking at ages 15-17 (32.4), and individuals who started drinking at 18 or older had fewer baseline lifetime AUD symptoms than those who started drinking at ages <15 or 15-17 (2.7 versus 5.7 and 4.5, respectively). Among individuals with incident abuse, similar patterns were observed with respect to age at onset (mean = 35.6, range = 19 to 87) and number of baseline AUD symptoms (mean = 1.8, range = 0 to 15) (data not shown).
