“Consistent with literature on early substance initiation and later illicit substance use, early onset of alcohol and polysubstance use is an important risk factor for IDU in adulthood.”
“ IDUs also had significantly greater proportions of early onset of alcohol (χ(2)=19.71, p<.01), cigarette (χ(2)=11.05, p<.01), marijuana (χ(2)=10.83, p<.01), and polysubstance use (χ(2)=23.48, p<.01) than non-IDUs.”