Marijuana use in New Zealand, 1990 and 1998.

AIMS To examine changes in marijuana use in a metropolitan region and a provincial/rural region in New Zealand between 1990 and 1998. METHODS Two random sample surveys of people aged 15 -45 years were carried out in Auckland and Bay of Plenty regions in 1990 and 1998, using a computer-assisted telephone interviewing system. RESULTS Use of marijuana in the last twelve months increased in the metropolitan sample from 18% to 22%, but not in the provincial area. Those who had ever tried marijuana increased from 43% of the total sample in 1990 to 52% in 1998. Use was higher among men than women, but had increased among women. There was a trend towards more frequent users of marijuana (ten or more occasions in the previous 30 days), from 2.4% to 3.2%. CONCLUSIONS Experience of marijuana was slightly more common in 1998 than in 1990, but increases in recent use were small and were found only in the metropolitan area. The increase in use was relatively limited: only one in five of each sample had used marijuana in the past year, and opportunity to use marijuana by non-users had not increased. Use was predominantly casual and social, and most who had tried marijuana no longer used the drug. However, the age at which first use occurred appeared to have declined.