Clinical and psychological effects of marihuana in man.

In the spring of 1968 we conducted a series of pilot experiments on acute marijuana intoxication in human subjects. The study was not undertaken to prove or disprove popularly held convictions about marijuana as an intoxicant, to compare it with other drugs, or to introduce our own opinions. Our concern was simply to collect some long overdue pharmacological data. In this article we describe the primitive state of knowledge of the drug, the research problems encountered in designing a replicable study, and the results of our investigations. Marijuana is a crude preparation of flowering tops, leaves, seeds, and stems of female plants of Indian hemp Cannabis sativa L.; it is usually smoked. The intoxicating constituents of hemp are found in the sticky resin exuded by the tops of the plants, particularly the females. Male plants produce some resin but are grown mainly for hemp fiber, not for marijuana. The resin itself, when prepared for smoking or eating, is known as “hashish.” Various Cannabis preparations are used as intoxicants throughout the world; their potency varies directly with the amount of resin present.’ Samples of American marijuana differ greatly in pharmacological activity, depending on their composition (tops contain most resin ; stems, seeds and lower leaves least) and on the conditions