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APPENDIX 3

World Health Organisation—Appraisal of Cannabis type Dependence

Drug Dependence of Cannabis (Marihuana) Type

It is not known with absolute certainty which of the chemical structures that have been isolated from Cannabis sativa L. is responsible for the typical cannabis effects, but these can nevertheless be described as constituting an entity that varies in degree according to the concentration of the active principle or principles in the plant and the preparations obtained therefrom, and to the mode of application. These effects are also producible by certain synthetic substances of similar chemical structure.

Among the more prominent subjective effects of cannabis, for which it is taken occasionally, periodically or chronically, are: hilarity, often without apparent motivation; carelessness; loquacious euphoria, with increased sociability as a result; distortion of sensation and perception especially of space and time with the latter reinforcing psychic dependence and being valued under special circumstances; impairment of judgment and memory; distortion of emotional responsiveness; irritability; and confusion. Other effects, which appear especially after repeated administration and as more experience is acquired by the user include; lowering of the sensory threshold, especially for optical and acoustical stimuli, thereby resulting in an intensified appreciation of works of art, paintings and of music; hallucinations, illusions, and delusions that predispose to antisocial behaviour; anxiety and aggressiveness as a possible result of the various intellectual and sensory derangements; and sleep disturbances.

In the psychomotor sphere, hypermotility occurs without impairment of coordination. Among somatic effects, often persistent, are injection of the ciliary vessels and oropharyngitis, chronic bronchitis and asthma; these conditions and hypoglycaemia, with ensuing bulimia, are symptoms of intoxication, not of withdrawal.

Typically, the abuse of cannabis is periodic but, even during long and continuous administration, no evidence of the development of physical dependence can be detected. There is, in consequence no characteristic abstinence syndrome when use of the drug is discontinued.

Whether administration of the drug is periodic or continuous, tolerance to its subjective and psychomotor effects has not been demonstrated.

Whereas cannabis often attracts the mentally unstable and may precipitate temporary psychoses in predisposed individuals, no unequivocal evidence is available that lasting mental changes are produced.

Drug dependence of the cannabis type is a state arising from chronic or periodic administration of cannabis or cannabis substances (natural or synthetic) Its characteristics are:

(a) Moderate to strong psychic dependence on account of the desired subjective effects.
(b) Absence of physical dependence, so that there is no characteristic abstinence syndrome when the drug is discontinued.
(c) Little tendency to increase the dose and no evidence of tolerance.

For the individual, harm resulting from abuse of cannabis may include inertia, lethargy, self-neglect, feeling of increased capability, with corresponding failure, and precipation of psychotic episodes. Abuse of cannabis facilitates the association with social groups and subcultures involved with more dangerous drugs, such as opiates or barbiturates. Transition to the use of such drugs would be a consequence of this association rather than an inherent effect of cannabis. The harm to society derived from abuse of cannabis rests in the economic consequence of the impairment of the individual's social functions and his enhanced proneness to a social and antisocial behaviour.