The National Commission on Marihuana and Drug Abuse

Marihuana - A Signal of Misunderstanding.

Chapter II

marihuana use and its effects

Tolerance and Dependence

Some tolerance does occur with prolonged heavy usage; large drug doses are necessary for the desired effects. Abrupt withdrawal does not lead to a specific or reproducible abstinence syndrome and physical dependence has not been demonstrated in man or in animals. The very heavy users studied did evidence strong psychological dependence, but were able to cease use for short periods of time. In these users,

withdrawal does induce, symptoms characteristic of psychological dependence. The anxiety, restlessness, insomnia, and other non-specific symptoms of withdrawal are very similar in kind and intensity to those experienced by compulsive cigarette smokers.

Although the distress of withdrawal exerts a very strong psychogenic drive to continue use, fear of withdrawal is, in most cases, not adequate to inspire immediate criminal acts to obtain the drug.