Early clinical manifestations of cannabis dependence in a community sample

In this research, the 'natural history' of cannabis dependence is probed, using data from a large epidemiological sample of cannabis users followed from 1981 through 1996, until most of these users had passed through the empirically derived period of risk for developing cannabis dependence.

The Baltimore Epidemiologic Catchment Area research group sampled, recruited, and assessed 3481 adults age 18+ years in 1981. Survivors were re-assessed roughly 13 years later. Among 599 cannabis users, a total of 37 had become cases of cannabis dependence during the follow-up interval; 41 had developed DSM-IIIR cannabis abuse without dependence; 521 had suffered insufficient problems to qualify as cases. Survival analysis methods were used to plot and study the cumulative occurrence of these problems in a primary contrast of the 37 dependence cases and 562 non-cases.

Subjectively felt loss of control over cannabis and continued cannabis use despite knowledge of harm seem to appear most rapidly among cases of cannabis dependence. In contrast, subjectively felt withdrawal symptoms tended to emerge later and for a much smaller proportion of dependence cases and non-cases.

The 5000+ person-years of follow-up experience provided by the cannabis users in this study give an unprecedented look at the natural history and clinical course of cannabis dependence. Distinctive features of early cannabis dependence may help differentiate cannabis users who progress to clinically significant dependence from those who remain non-dependent.