Heroin use was determined by responses to questions on whether participants had ever used heroin, even once, and when they last used it. Of the 1094 individuals without missing data, about 93% had never tried heroin (n = 1023), about 6% used it but not in the past-year (n = 62), and about 1% used it in the last-year (n = 9). Of the nine past-year current users, three individuals used heroin daily or almost daily, two used it from once or twice a week to once or twice a month, and four used it between once and eleven times a year. Given the small number of current heroin users, and given that eight out of nine current heroin users were also current cocaine users, and 87% of the former heroin users were also former or current cocaine users, we examined the association of personality traits with cocaine or heroin use. As expected in a population-based sample, we also found substantial overlap among the other drugs used. Of the former and current smokers, 52% had also used marijuana, 21% cocaine,
