Long Term Marijuana Users May Experience Withdrawal

By Lauren Gilmore

Two studies have been performed that suggest that long-term marijuana users may experience withdrawal symptoms. The symptoms that researchers are focusing on are mostly behavioral including anxiety, irritability, and aggression. Experts believe that to avoid the unpleasant experiences associated with abstinence people may continue to abuse the substance.

A study conducted by Dr. Elena Kouri and her colleagues tested the behavioral differences between long-term heavy marijuana users and infrequent users once they abstained. The regular users had smoked marijuana at least 5000 times in their life or the equivalent of smoking once a day for 13 years; the occasional smokers had only smoked 50 times or less in their life, or had smoked daily at one time but not more than once a week in the past three months. The subjects had to refrain from marijuana use for 28 days, which was monitored by conducting urinalysis.

Researchers in this study were concerned with measures of aggression. In order to measure aggression, the researchers used a computerized test which monitored motor skills and other physiological features. Aggression was measured the first day of the study and then again after one, three, seven, and 28 days of abstinence.

The results revealed that the regular users of marijuana had significantly more aggressive responses after one, three, and seven days of abstinence. On days three and seven, this group scored more than twice as many aggressive responses than the group of infrequent users. On the twenty-eighth day, there was no significant difference between the two groups. The subjects did not display any aggressive behavior outside of the laboratory, which suggests that this may only occur in a testing situation. However, it is concluded that withdrawal from regular use is associated with certain temporary aggressive traits.

The Maternal Substance Abuse and Child Development Project is funded in part by the Georgia Department of Human Resources Division of Public Health.

The Maternal Substance Abuse and Child Development Study is under the direction of Claire D. Coles Ph.D., with the Department of Psychiatry and Behavioral Science, Emory University School of Medicine. For more information, please contact: Claire D. Coles: ccoles@emory.edu Karen K. Howell: khowell@emory.edu