A possible hypothesis underlying the telescoping effect observed among those with late onset is that early-onsetting youth may substitute drinking with other drugs, thus delaying progression to heavier drinking. As Table 1 indicates, youth reporting first drink by age 10 had greater substance use. However, early onsetters were more likely to drink frequently and were more likely to be alcohol dependent, suggesting that drug use was supplementing, not replacing, alcohol use. Also contradictory to a drug replacement mechanism is that alcohol was more likely to be a treatment focus for early- and mid-onsetters than late onsetters.
