In a national survey conducted in 1994, 29.3% of all respondents reported t
hat they had used cannabis at least once, 7.3% reported using at least once
during the year of the survey, and 2.0% reported using cannabis at least o
nce a week during the year of survey. Nonusers and those with different pat
terns of cannabis use could be distinguished by age; gender; the use of alc
ohol, tobacco, and other drugs; and involvement with drug users. Frequent c
annabis use at the time of the survey was associated with "heavy" drinking
and drinking problems, drinking and driving, driving within 2 hours of usin
g cannabis, and the use of other drugs, especially among young males. The a
ssociation between regular cannabis use, "heavy" drinking, and other risk b
ehaviors poses challenges to prevention and harm-reduction initiatives.