Among all frequent cannabis users, those with ≥3 cannabis withdrawal symptoms reported a median duration of 105 weeks, compared to 157 weeks in those who experienced <3 symptoms (non-parametric comparison of medians, p<0.01). Those reporting 3 cannabis withdrawal symptoms had higher quantity of cannabis use versus those with <3 symptoms (mean 4.3 joints versus 3.6 joints; t=2.6, p=0.01). There was no statistically significant difference in the mean age of onset between those reporting ≥3 symptoms vs. <3 symptoms (17 vs. 18, p=0.10). Those with ≥3 symptoms were more likely to have a family history of drug problems than those with <3 symptoms (χ2 =8.3, df=1, p<0.006). Results were essentially the same in the subsample of cannabis-only users, except that those with ≥3 symptoms had a significantly younger age of onset (15.9 vs. 17.4, p=0.04).
