Attempts to stop or reduce marijuana use in non-treatment seekers.

Daily marijuana smokers (n=19) who intended to quit or reduce in the next month on their own called a phone each night for 28 nights to report marijuana use and reported intentions to change at the end of each week. Outcomes did not differ between those who initially planned to reduce vs. quit in the next month. Participants averaged three attempts to reduce and one attempt to quit during the 28 days. Participants reduced on 11% and abstained on 14% of days. Most participants were successful in reducing or abstaining on half or more of the days they attempted; however, only four participants (21%) reduced > or =50% for > or =7 consecutive days and only two (10%) abstained for that long. Abstinence or reduction did not appear to change alcohol or caffeine use. We conclude: (a) initial intentions are poor predictors of outcomes, (b) most users make multiple, short-lived attempts to change, (c) reduction was as common as abstinence, (d) many attempts to change are initially successful but few persist, and (e) other drug use does not appear to worsen with marijuana reduction or abstinence.