NEW YORK, Apr 20 (Reuters Health) -- People who have smoked marijuana daily for many years display more aggression when they are going through withdrawal than do infrequent and former users, according to study results reported by researchers at Harvard University in Boston, Massachusetts.

The study is "further evidence that a withdrawal syndrome is associated with abstinence from long-term marijuana use," according to a statement issued by the National Institute on Drug Abuse (NIDA), which funded the study.

"People addicted to marijuana may continue to use the drug at least partly to prevent the onset of withdrawal symptoms," said NIDA Director Dr. Alan I. Leshner in a statement. "Identifying the exact nature of this syndrome is crucial to developing treatment strategies for those attempting to stop their marijuana use."
(Marijuananews note: Leshner is prohibitionism’s little joke on the scientific community. Notice that there is no other consequence of cessation reported. Try that with really addictive drugs.)

NIDA reports that marijuana "is the most widely used illicit drug in the United States." According to the 1997 National Household Survey on Drug Abuse, more than 11 million Americans used marijuana in the past month.

The Harvard researchers studied the behavior of 17 long-term heavy users of marijuana and 20 people who were infrequent or former smokers. The subjects were placed in a chamber facing a computer monitor and a response panel that had two buttons, labeled A and B. They were told that they would compete against another subject in a separate chamber, although they were actually responding solely to the computer.

If the person pressed the A button 100 times, he or she gained 1 point, while pressing the B button 10 times subtracted points from the opponent. The subjects participated in five sessions, scheduled during marijuana use in the case of current users, and after days 1, 3, 7 and 28 of abstinence.

Current marijuana users became significantly more aggressive 3 and 7 days after withdrawal, compared with those who were infrequent or former marijuana users, according to the NIDA.

The lead investigator, Dr. Elena Kouri of Harvard Medical School in Boston, Massachusetts, told Reuters Health that the computer test has been used in a number of studies to measure aggressive responses to other substances.

She emphasized that the new results do not suggest that heavy marijuana users would be aggressive outside the laboratory setting.

The study findings are published in the April issue of the journal Psychopharmacology.

SOURCE: Psychopharmacology April 1999.

(Marijuananews note: Notice the different spin. This takes "withdrawal" as proven, when it actually is only a possible inference.)
WASHINGTON (Reuters) - People who smoke marijuana every day become more aggressive when they quit, adding to evidence that users can go through withdrawal, U.S. researchers said Tuesday.

Dr. Elena Kouri and colleagues at Harvard University said they had shown objectively that when people stop smoking "pot," there is a clear withdrawal syndrome.

"This syndrome, although less dramatic than the withdrawal syndrome associated with alcohol, opiate or cocaine withdrawal, may contribute to relapse among those dependent on marijuana," Dr. Alan Leshner, head of the National Institute of Drug Abuse (NIDA), which funded the study, said in a statement.

"People addicted to marijuana may continue to use the drug at least partly to prevent the onset of withdrawal symptoms."

But finding out why this happens may help researchers come up with better treatments for users, he said.

See
Australian Study Of Very Heavy Cannabis Users
Shows Most Can Quit With 16 Weeks of Counseling
and links

Writing in the journal Psychopharmacology, Kouri’s team said they used a computer test that pitted 17 long-term heavy users of marijuana against 20 infrequent or former smokers. The volunteers did not know that aggressive behavior was being studied.

They were told that pressing a button labeled "A" 100 times would win them one point, worth 50 cents. Pressing a button labeled "B" 10 times would take a point away from an imaginary opponent of the same sex who was supposedly sitting in another cubicle.

The computer beeped to show that the "opponent" was taking a point away from the volunteer.

The tests were given over a period of 28 days, during which the users did not smoke marijuana. The heaviest users became significantly more aggressive during the first week, an indication that they were going through withdrawal.

"Most of the studies that have been published on marijuana withdrawal symptoms in people have relied on self-report," Kouri said. Users have reported feeling irritable, but this was the first test to verify this objectively, she said.

According to the National Household Survey on Drug Abuse, published in 1997, more than 11 million people had smoked marijuana in the one-month period that the survey was done, making it the most widely used illegal drug.

"Although it is difficult to be certain of the exact prevalence of cannabis addiction in the United States, I can tell you anecdotally that we had no difficulty recruiting dozens of people between the ages of 30 and 55 who have smoked marijuana at least 5,000 times," Dr. Harrison Pope, who led the study, said.