UVM Theses and Dissertations
Format:
Print
Author:
Vandrey, Ryan G.
Dept./Program:
Psychology
Year:
2005
Degree:
PhD
Abstract:
A valid and reliable cannabis withdrawal syndrome has recently been characterized in both inpatient and outpatient laboratory studies. The clinical significance of the syndrome, however, remains uncertain. One method of assessing the significance of cannabis withdrawal is to compare it directly to an established withdrawal syndrome. Two prior studies suggest the relative magnitude and time course of cannabis withdrawal is similar to that observed for the well-defined tobacco withdrawal syndrome. Methodological limitations of these studies necessitate further comparison of these two withdrawal syndromes prior to making strong assertions regarding their relative severity. Two studies were conducted to extend the initial comparisons. Experiment 1 was a within-subject comparison of cannabis, tobacco, and combined cannabis and tobacco withdrawal using an ABACAD design in adult users of both substances.
Participants each completed 5- day periods of abstinence from each substance alone, and both combined in a randomized order. Primary analyses indicated that withdrawal during cannabis and tobacco alone was of a similar magnitude for symptoms common to both withdrawal syndromes, but that withdrawal from both was more severe than for each substance alone, especially on Day 2. Significant variability was observed between subjects with an equal number of participants indicated withdrawal from cannabis, tobacco, or both was most difficult. Secondary analyses suggested that withdrawal severity was related to amount of substance use in most conditions, but also that withdrawal during abstinence from cannabis was slightly negatively correlated with withdrawal during abstinence from both substances.
Experiment 2 was a telephone survey study conducted with adults who had recently made an attempt to quit use of cannabis or tobacco. Results indicated that the frequency and magnitude of withdrawal effects were similar across substances for symptoms that are common to both cannabis and tobacco, and expected differences were observed for some symptoms unique to one of the two substances. In addition to the direct comparison of cannabis and tobacco abstinence effects, a novel investigation in Experiment 2 documented that a majority of cannabis users believe that cannabis withdrawal symptoms had contributed to past failed quit attempts and periods of continued use, thus providing an additional method for judging clinical importance.
Evidence from these two studies extend the evidence supporting the conclusion that withdrawal from heavy cannabis use is as severe as that from heavy tobacco use, and provide an initial indication that users of cannabis believe such symptoms make quit attempts more difficult and contribute to relapse. Prospective research is needed to corroborate the observation that withdrawal is related to relapse. Moreover, exploration of factors (neurobiological, psychosocial, etc.) that predict who experiences greater withdrawal severity from different drugs and drug combinations is needed.
Participants each completed 5- day periods of abstinence from each substance alone, and both combined in a randomized order. Primary analyses indicated that withdrawal during cannabis and tobacco alone was of a similar magnitude for symptoms common to both withdrawal syndromes, but that withdrawal from both was more severe than for each substance alone, especially on Day 2. Significant variability was observed between subjects with an equal number of participants indicated withdrawal from cannabis, tobacco, or both was most difficult. Secondary analyses suggested that withdrawal severity was related to amount of substance use in most conditions, but also that withdrawal during abstinence from cannabis was slightly negatively correlated with withdrawal during abstinence from both substances.
Experiment 2 was a telephone survey study conducted with adults who had recently made an attempt to quit use of cannabis or tobacco. Results indicated that the frequency and magnitude of withdrawal effects were similar across substances for symptoms that are common to both cannabis and tobacco, and expected differences were observed for some symptoms unique to one of the two substances. In addition to the direct comparison of cannabis and tobacco abstinence effects, a novel investigation in Experiment 2 documented that a majority of cannabis users believe that cannabis withdrawal symptoms had contributed to past failed quit attempts and periods of continued use, thus providing an additional method for judging clinical importance.
Evidence from these two studies extend the evidence supporting the conclusion that withdrawal from heavy cannabis use is as severe as that from heavy tobacco use, and provide an initial indication that users of cannabis believe such symptoms make quit attempts more difficult and contribute to relapse. Prospective research is needed to corroborate the observation that withdrawal is related to relapse. Moreover, exploration of factors (neurobiological, psychosocial, etc.) that predict who experiences greater withdrawal severity from different drugs and drug combinations is needed.