“Adolescents are dependent at a lower frequency and quantity of use than adults: the differences diverge as level of use increases. Twice as many adolescents as adults who used marijuana near-daily or daily within the last year were identified as being dependent (35% versus 18%). Frequency and quantity of use each retained a unique effect on dependence, but frequency appeared to be more important than quantity in predicting last year dependence.” (Chen et al, 1997)
“This higher dependence liability of adolescents is sometimes used as an argument against the medical use of cannabis. However, this argument is not used with other medicines, such as the opiates. The IOM report states that permitting the medical use of marijuana would not increase non-medical uses. The report also addresses the suggestion by opponents of medical use that approving marijuana as a medicine "sends the wrong message." The authors say there is "no convincing data to support this concern," and they note that "this question is beyond the issues normally considered for medical uses of drugs." (Joy et al. 1999).
"A variety of estimates have been derived from U.S. studies in the late 1970s and early 1980s, which defined cannabis use and dependence in a variety of ways. These studies suggested that between 10 and 20 per cent of those who have ever used cannabis, and between 33 and 50 per cent of those who have had a history of daily cannabis use, showed symptoms of cannabis dependence (see Hall, Solowij & Lemon, 1994). A more recent and better estimate of the risk of meeting DSM-R.III criteria for cannabis dependence was obtained from data collected in the National Co morbidity Study (Anthony, Warner & Kessler, 1994). This indicated that 9 per cent of lifetime cannabis users met DSM-R-III criteria for dependence at some time in their life, compared to 32 per cent of tobacco users, 23 per cent of opiate users and 15 per cent of alcohol users." (Hall et al. 1999).
"Tolerance develops to the receptor-mediated effects of THC with continued usage. However, there are distinctions in their degree with different effects. Discontinuation of chronic THC use may cause rebound phenomena (transient increase in intraocular pressure, loss of appetite, etc.). Some chronic users report withdrawal symptoms after abrupt cessation. This withdrawal syndrome is characterized by irritability, agitation, sleep disorder, hyperhidrosis and loss of appetite. It is generally mild. Cannabis dependency is less determined by physical than by psychological factors. Dependency and abuse potential of therapeutically employed Delta9-THC is low." (Grotenhermen 2002).
"It is suggested that the studies conducted to date do not provide a strong evidence base for the drawing of any conclusions as to the existence of a cannabis withdrawal syndrome in human users, or as to the cause of symptoms reported by those abstaining from the drug. On the basis of current research, cannabis cannot be said to provide as clear a withdrawal pattern as other drugs of abuse, such as opiates. However, cannabis also highlights the need for a further defining of withdrawal, in particular the position that rebound effects occupy in this phenomenon. It is concluded that more controlled research might uncover a diagnosable withdrawal syndrome in human users and that there may be a precedent for the introduction of a cannabis withdrawal syndrome before the exact root of it is known." (Smith 2002).