(Haney et al., 1999; Kouri and Pope, 2000; Budney et al., 2001, 2002, 2004), this is not surprising, as subjects were seen well within a 24 hour period from their last use. Of course, despite subjects’ own report of no overt withdrawal symptoms, we cannot rule out the possibility that some of the observed differences are not related to short term withdrawal that occurs at a biologic and not psychological level, and thus, remains undetectable to subjects themselves. One strength of the current study, however, is the naturalistic design, which allowed for the examination of marijuana smokers who were not asked to complete an extended period of abstinence. Study findings are therefore more likely to be reflective of chronic marijuana smokers in everyday life and not those who are constrained by laboratory based situations. Future investigations should include more sensitive, quantifiable measures related to withdrawal from marijuana, especially given that most of the withdrawal syndrome in marijuana smokers does not begin until at least 24 hours after last use. An important next step in this research is the examination of a sample of chronic marijuana smokers who complete a lengthy period of abstinence in order to assess whether the findings
