The Effects of Marijuana

PRACTICALLY everybody, whether doctor or layman, pothead or puritan, has been expressing dogmatic opinions for years about the effects of marijuana on its users. It therefore came as a surprise last week when a team of Harvard and Boston University investigators reported that they had just conducted the first truly scientific tests ever made on the subject. Their findings, which appear in Science magazine, confirm some popular ideas about marijuana's effects and expose others as completely false. The drug, the investigators concluded, "appears to be a relatively mild intoxicant, with minor, real, shortlived effects." It seems to have a greater effect on thinking and perception than on reflexes and coordination.

The leader of the research team was Andrew T. Weil, 26, a senior medical student at Harvard who graduated last summer and is now an intern at San Fran cisco's Mount Zion Hospital. Weil hopes to make a career of research into drugs that influence the mind. With marijuana, he learned--the hard way--about some of the research difficulties involved. Pos session or use of marijuana is illegal, except by hard-to-get federal dispensation. Universities are skittish about sponsoring research that might incur public or congressional criticism, and it took Weil a frustrating year to get the study approved and organized. Then he did it up right: he got his marijuana from the Federal Bureau of Narcotics and Dangerous Drugs itself, and got the attorney general of Massachusetts to agree that nobody would be arrested for taking part in the experiments.

Inhale Deeply. Weil organized two study groups composed of men aged 21 to 26 who had no known psychiatric disorder. Nine of the men had never smoked marijuana (although most said they had wanted to); the other eight were regular users.

Instead of using a psychedelic setting in a dimly lit pad, the researchers ran their tests in a square but comfortable laboratory. They rolled their own cigarettes of three kinds: one of low-strength marijuana, one of high-strength and a third of male hemp stalks, which gave off the same odor but contained none of the psychoactive ingredient. The subjects smoked two reefers within a few minutes in each three-hour session, which included both psychological and physiological tests. The study was double-blind--neither the testers nor the smokers knew, until afterward, which were the dummies and which the weak and strong reefers. The subjects smoked the different kinds of cigarettes in random order at successive sessions.

Red Eyes. The first thing that became clear was that those who had never smoked marijuana before got no reaction in their first session on pot. This tallies with the experience of many unscientific potheads; they achieved no "high" the first time. The only exception to this was a man who had expressed a desire to get high--and did so quickly. He became euphoric and laughed continuously. Yet one subject who had said that he did not intend to get high never did, even in successive sessions that included heavy doses of marijuana.

Nor could the novices estimate the strength of their reefers. They guessed right eight times out of nine on the dummy cigarette, and six times on the mild reefer, but eight out of nine guessed "mild" when they were really getting a puff with a big clout.

The physiological changes were modest. Novice smokers registered an increase in heart rate of 16 beats a min ute on the average (only a small fraction of what occurs at orgasm), while habitual users, who tended to start off with a slower heartbeat, showed a greater but not alarming increase. There was no significant increase in breathing rates. The tests confirmed the widely reported "redeye" effect of pot: the small blood vessels in the whites of the eyes became dilated, and the higher the dose the greater the dilation.

One "well-known" effect of marijuana did not occur. Many policemen say that they can spot a pothead by the dilation of his pupils. Not so, say the researchers. Or if so, the cause is not marijuana but the fact that potheads have done their smoking in dimly lit rooms, where the pupils naturally dilate. The tests also failed to confirm an assumption that pot causes an increase in appetite by lowering the level of blood sugar. The subjects showed no changes in blood sugar, so why marijuana smokers get so hungry remains a mystery.

Stretched Time. The psychological tests produced other interesting, but still inconsistent results. The men's performance was unaffected in a test that demands signaling when a particular letter appears in a group of letters flashed on a screen. Another test, in which numbered arithmetical symbols must be put in correspondingly numbered spaces, produced a paradoxical result. The marijuana novices did poorly on this for as long as H hours after smoking, but the habitual users improved their ordinary performance when under pot. A similar discrepancy appeared in a test requiring the subject to keep a stylus on a moving spot. The novices did badly, but the habitual users got better at it.

The tests confirmed the blues player's notion that time seems to be stretched under the influence of pot. Some subjects who had previously been able to gauge a five-minute interval with fair accuracy guessed that the same interval was ten minutes after they had had their smokes. One subject said: "I realize why they took our watches. There was a sense of the past disappearing, as happens when you're driving too long without sleeping. It was the same tonight with eating a sandwich. I'd look down and discover that I'd just taken a bite, but I hadn't noticed it at the time," Another: "Time seemed very drawn out. I'd keep forgetting what I was doing, especially on the first test, but somehow, every time the critical letter came up, I found myself pushing the button."

Why do marijuana users get little or no reaction the first time, and greater highs later? The phenomenon may represent, Weil and his colleagues suggest, a strange case of "reverse tolerance." But, as with many other things about marijuana, they cannot be sure,

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