I. The Weil-Zinberg Study
In 1968 Andrew Weil, then a medical student at Harvard University, together with Norman Zinberg, a Harvard psychoanalyst, conducted a series of experiments to determine the basic physical and psychological effects of marijuana on human beings This study, which took place at Boston University, represented the first double-blind experiments with marijuana; until the study was completed, neither the subjects nor the experimenters knew who had been smoking a drug and who had been smoking a carefully disguised placebo.
Here are the conclusions, as reported in the article, "Clinical and Psychological Effects of Marihuana in Man," Science 162 (13 December 1968):1234-42.
1. It is feasible and safe to study the effects of marijuana on human volunteers who smoke it in a laboratory.
2. In a neutral setting persons who are naive to marijuana do not have strong subjective experiences after smoking low or high doses of the drug, and the effects they do report are not the same as those described by regular users of marijuana who take the drug in the same neutral setting.
3. Marijuana-naive persons do demonstrate impaired performance on simple intellectual and psychomotor tests after smoking marijuana; the impairment is dose-related in some cases.
4. Regular users of marijuana do get high after smoking marijuana in a neutral setting but do not show the same degree of impairment of performance on the tests as do naive subjects. In some cases, their performance even appears to improve slightly after smoking marijuana.
5. Marijuana increases heart rate moderately.
6. No change in respiratory rate follows administration of marijuana by inhalation.
7. No change in pupil size occurs in short-term exposure to marijuana.
8. Marijuana administration causes dilation of conjunctival blood vessels.
9. Marijuana treatment produces no change in blood sugar levels.
10. In a neutral setting the physiological and psychological effects of a single, inhaled dose of marijuana appear to reach maximum intensity within one-half hour of inhalation, to be diminished after one hour, and to be completely dissipated by three hours.
II. The Goode Study
In a study of 200 marijuana smokers conducted in 1967 and published in 1970 as The Marijuana Smokers, Erich Goode, a sociologist, reported the following results as the most common effects of smoking marijuana. The table appears in Goode's book Drugs in American Society (New York, 1972), page 48.
Subjective Effects of Marijuana: Goode 1970 EFFECT PERCENTAGE OF
RESPONDENTSMore relaxed, peaceful, calmer 46 Senses more "turned on," more sensitive, perceptive 36 Think deeper, have more profound thoughts 31 Laugh more; everything seems funnier 29 Exaggeration of mood; things take on greater significance 25 Time seems slowed down, stretched out 23 Become withdrawn, introverted, privatistic 22 Generally feel nice, groovy, pleasant, fun 21 Mind wanders, free-associates; stream of consciousness 21 Feel dizzy, light-headed 20 Feel lazy, lethargic, don't want to move 19 Feel light, airy, floating, elevated 18 Feel "happy" 18 Forget things, have memory gaps 18 Feel freer, more unrestrained, less inhibited 18 Stimulation of the senses is more enjoyable 18 Become hungry, want to eat more; appetite stimulated 17 Musical ear sharper, more acute, sensitive, accurate 17 Enjoy music more; greater pleasure listening to music 16 Feel paranoid 15
III. The Tart Study
A year after The Marijuana Smokers appeared, Charles Tart, a California psychologist, published On Being Stoned: A Psychological Study of Marijuana Intoxication. Tart distributed 750 questionnaires among California smokers, of which 150 were returned. Tart used a forced-answer checklist, so that a higher percentage of respondents reported a specific effect than was true in Goode's study, where smokers had to think up the individual effects on their own. This table appears in Drugs in American Society, page 49.
Subjective Effects of Marijuana: Tart 1971 EFFECT VERY OFTEN
OR USUALLYSOMETIMES
OR RARELYNEVER Hear subtle changes in sounds 95 4 1 Distance walking seems changed 78 21 3 Taste seems different 78 18 1 Sleep easier and better 76 14 3 Enjoy eating more; eat more 75 23 1 Time passes slowly 74 24 1 Physically relaxed, inactive 72 27 1 Can "come down" at will 70 21 5 Feel more childlike, open 68 26 5 Can understand songs better 66 30 4 Sense of touch more exciting 65 30 4 Accept things easier 64 32 2 Hard to play social games 62 28 6 Almost always feel good 61 20 5 Memory span shortened 60 36 3 Spatial separation of music 60 27 13 Mind's eye sharper 60 25 12 Difficult to read 57 29 9 See visual patterns in things 56 35 6 Sexual orgasm more pleasurable 56 31 6 Meaningful insights come to mind 55 40 3 Touch takes on new qualities 55 39 5 Deeper insights into others 55 38 7 Appreciate subtle humor in others 54 43 2 Completely present-oriented 53 44 3 Forget to finish things 53 42 4 Moving about seems smoother 53 37 7 Less boisterous at parties 52 39 5 Aware of body-emotion connection 50 36 13 Accept contradictions easier 50 32 11
IV. Other Studies
In 1971 a survey conducted by three physicians (James Halikas, Donald Goodwin, and Samuel Guze) was described in the Journal of the American Medical Association z17: 6gz-g4. A hundred regular marijuana smokers were asked to complete a checklist questionnaire. This table was compiled by Erich Goode, and it appears in Drugs in American Society, page 51.
Subjective Effects of Marijuana: Halikas, Goodwin, and Guze 1971 EFFECT USUALLY OCCASIONALLY ONCE OR NEVER Euphoria 82 17 1 Relaxation 79 21 0 Keener sound sense 76 21 3 Peaceful 74 25 1 Increased sensitivity 74 23 3 Increased hunger 72 24 4 Time slowed down 62 35 3 Increased thirst 62 32 6 Dry throat and mouth 61 38 1 Floating sensation 45 49 6 More talkative 37 51 12 Hunger for sweets 37 43 20 Laughing and giggling 36 60 4 Heightened sex feeling 34 59 7 Heightened sex arousal 33 59 8
A fifth study was conducted by Joel Hochman and Norman Brill, physicians at the University of California at Los Angeles. In 1971 a random sample of UCLA's student body was asked to respond to a forced-alternative checklist, with two categories of marijuana use by frequency (often or always, and never) and two levels of use: chronic and occasional. This table was extracted by Erich Goode from the UCLA study and appears in Drugs in American Society, page 52.
Subjective Effects of Marijuana: Hochman and Brill 1971 OFTEN OR ALWAYS NEVER EFFECT CHRONIC OCCASIONAL CHRONIC OCCASIONAL Hunger 85 72 3 12 Increased sex pleasure 83 50 3 20 Decreased tension 82 57 5 14 Intensified taste 80 65 6 17 Intensified hearing 79 66 6 15 Mellowness 78 59 6 12 Very happy (euphoria) 70 59 3 12 Thirst 70 57 4 17 Increased abstract thinking 70 46 6 20 Time passes slowly 66 57 6 18 Increased self-awareness 62 45 11 19 Increased sexual appetite 60 43 6 20 Desire for sweets 55 37 11 29 Sleepiness 52 50 4 11 Increased understanding of others 47 34 14 27 Increased creativity 45 25 16 35 Increased ability to communicate 42 25 16 37 Clarifies thinking 35 20 13 33 Decreased attention span 28 31 28 30 Paranoid thoughts 18 19 25 39 Able to function better 18 6 31 52 Confusion 17 15 28 32 Decreased ability to communicate 17 19 33 37 Incoordination 15 17 28 32 Irrational ideas 13 16 38 42 Dulls thinking 12 16 28 34 Rapid heartbeat 10 14 54 56 Hallucinations 6 7 44 61 Dizziness 6 5 61 59 Sadness 4 6 29 36 Shortness of breath 4 4 71 80 Increased tension 3 7 72 64 Chills 3 6 78 79 Decreased sexual appetite 2 3 75 70 Decreased sexual pleasure 1 4 85 78 Nausea 0 1 87 84 Annotated Bibliography