1. INTRODUCTION

A WHO Scientific Group on the Use of Cannabis met in Geneva from 8 to 14 December 1970.

Dr L. Bernard, Assistant Director-General, opened the meeting on behalf of the Director-General. He said that a variety of psychoactive cannabis preparations have been used for many centuries in some parts of the world, whereas in others they have been used little or not at all. Their use in a given locality has often been largely confined to particular socio-economic groups. There now appears to be a rapidly increasing number of persons in some traditionally low-use geographic areas and sociocultural groups who have at least tried these preparations. Those involved in this increased use are predominantly younger persons, and in numerous localities all the socio-economic groups appear to be represented.

In relation to the increased use of cannabis, an often spirited debate has developed in many parts of the world about the effects of cannabis on man and the need for legal restraints on the availability of cannabis preparations. An authoritative examination of the subject needs to be undertaken, from a scientific point of view, to assess present knowledge of the effects of the use of cannabis on man to indicate where further research is needed, and to suggest possible approaches to such research. This was the task before the Group.