Schaffer Library of Drug Policy

Marihuana: A Signal of Misunderstanding

Marijuana -- Factors Influencing Psychopharmacological Effect - Dose-Response Relationship

US National Commission on Marihuana and Drug Abuse

Table of Contents
I. Marihuana and the Problem of Marihuana
Origins of the Marihuana Problem
The Need for Perspective
Formulating Marihuana Policy
The Report
II. Marihuana Use and Its Effects
The Marihuana User
Profiles of Users
Becoming a Marihuana User
Becoming a Multidrug User
Effects of Marihuana on the User
Effects Related to Pattern Use
Immediate Drug Effects
ShortTerm Effects
Long Term Effects
Very Long Term Effects
III. Social Impact of Marihuana Use
IV. Social Response to Marihuana Use
V. Marihuana and Social Policy
Drugs in a Free Society
A Social Control Policy for Marihuana
Implementing the Discouragement Policy
A Final Comment
Ancillary Recommendations
Legal and Law Enforcement Recommendations
Medical Recommendations
Other Recommendations
Letter of Transmittal
Members and Staff
History of Marihuana Use: Medical and Intoxicant
II. Biological Effects of Marihuana
Botanical and Chemical Considerations
Factors Influencing Psychopharmacological Effect
Acute Effects of Marihuana (Delta 9 THC)
Effects of Short-Term or Subacute Use
Effects of Long-Term Cannabis Use
Investigations of Very Heavy Very Long-Term Cannabis Users
III. Marihuana and Public Safety
Marihuana and Crime
Marihuana and Driving
Marihuana - Public Health and Welfare
Assessment of Perceived Risks
Preventive Public Health Concerns
Marihuana and the Dominant Social Order
The World of Youth
Why Society Feels Threatened
The Changing Social Scene
Problems in Assessing the Effects of Marihuana
Marihuana and Violence
Marihuana and (Non-Violent) Crime
Summary and Conclusions: Marihuana and Crime
Marihuana and Driving
History of Marihuana Legislation
History of Alcohol Prohibition
History of Tobacco Regulation
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Factors Influencing Psychopharmacological Effect


A major advance has been a quantification of dose of THC in relation to clinically observable phenomena. This has been extensively studied over a wide dose range for marihuana (Rodin and Domino, 1970; Melges et al., 1970; Tinklenberg et al., 197O; Weil et al., 1968; Meyer et al., 1971; Clark and Nakashima, 1968; Clark et al., 1970; Jones and Stone, 1970; Mayor's Committee, 1944; Manno et al., 1970) and Delta 9 tetrahydrocannabinol (Isbell et al., 1967; Waskow et al., 1970; Hollister et al., 1968; Perez-Reyes and Lipton, 1971; Lemberger et -al., 1971; Dornbush and Freedman, 1971).

Investigations by Isbell et al. (1967), Kiplinger et al. (1971) and Renault et al. (1971) have clearly demonstrated that when reliable quantities of smoked marihuana or THC are delivered to the subject, a reproducible linear dose-dependent effect occurs on indices of physiologic, psychomotor, and mental performance as well as on mood and subjective experiences over a dose range of 12.50 to 200 micrograms of Delta 9 THC per kilogram of body weight.

In a 154 pound man this is comparable to consuming 0.88 to 17.5 milligrams of Delta 9 THC or 88 to 150 milligrams of marihuana containing one percent Delta 9 THC. It is generally assumed that good quality marihuana available in the United States contains 1% Delta 9 THC and an average marihuana cigarette consists of 500 milligrams of marihuana; thus, 5 milligrams of Delta 9 THC (Hollister, 1971).

As with most drugs, the larger the dose taken, the greater the psychopharmacologic effect. Isbell et al. (1967) noted that clinical syndromes vary from a mild euphoric feeling of relaxation at low doses (25 micrograms per kilogram) to an intensive hallucinogenic-like experience at high doses (250 micrograms per kilogram).

Probably the duration of use will vary considerably depending on cultural acceptance or rejection (McGlothlin, 1972).

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