Fig. 1
Cumulative survival probability of smoking, alcohol use, cannabis use, illicit drug use, and sexual activity engagement and pregnancy through age 18 ya. a As age of first smoke, alcohol use, and sexual activity were primarily determined from self-reported integer age, these curves follow a stepwise decline in contrast to the more gradual declines in the marijuana use, illicit drug use, and pregnancy curves, which were primarily determined from the participant’s exact calendar age at the study visit