tient complaint,” he said. “While treatments have been developed for addictions from alcohol to nicotine and narcotics, none exists for the cannabis dependent. This research will help the field define what cannabis is and is not, and how to treat it.”
Studies at the University of Michigan in 1994 and 2004 show that one in every nine or 10 people who tries marijuana becomes dependent.
In the commonly used medical reference manual for psychiatric disorders, there is precise information about intoxication, dependence and withdrawal from substances ranging from alcohol to nicotine to heroin. But there is no information on cannabis.
And if it isn't listed in the manual, it doesn't exist in the treatment world and, perhaps more importantly, in the eyes of health insurance companies, said Dr. Ivan Montoya, who is with the NIDA's division of pharmacotherapies and medical consequences of drug abuse.
Mason said there is proof in animal and human studies of a withdrawal syndrome for cannabis. Like with nicotine, relapsing with marijuana gets rid of the symptoms, she said.
Two of the most frequent, long-lasting symptoms seen in people trying to stop smoking marijuana are sleep disturbances, such as vivid bad dreams, and negative behavioral affects, such as anxiety, anger and irritability, she said.
The symptoms are more subtle than withdrawal from other substances, such as alcohol. But alcohol clears from the system in a couple of days, she said.
Part of the problem with marijuana is its long half-life. Because it can be detected in a person's body 30 days after the last use, withdrawal symptoms can last at least that long, Mason said.
And other addiction treatment specialists point out that marijuana lingers indefinitely in some human tissue. So how long does the drug affect someone's physical functions and thought process?
An objective of Mason's work will be to study all the manifestations of the withdrawal, including stress hormones that are released, subjective effects reported by the patients and the effect on sleep and mood.
The study will research the effect marijuana has at different stages on development, comparing teens between the ages of 15 through 18, whose brains are still developing, and young adults ages 21 through 30.
The research will investigate how cannabis affects the capacity for learning, as well as the ability to make judgments and control impulses, which are cognitive processes that are needed for treatment, she said.
The study will involve neurophysiological testing and functional imaging of the brain, to determine how long the effects last, Mason said.
The project will also be able to take advantage of what Montoya said have been tremendous advances in the science of marijuana in recent years, including the presence of receptors in the brain that react to it.
“The thing that troubles a lot of us is that (marijuana) has such an appeal to younger people, and in recent time we have learned that the adolescent brain is so different in many ways that the final adult version,” said Dr. Reese Jones, a psychiatry professor at the University of San Francisco. “There is a lot of reason to think that all these issues may be a bigger deal in younger people.”
Recruitment for the study will be conducted through advertising and a Web site. Mason does not expect difficulty finding participants.
She is currently running a separate, more narrow study on treatment for cannabis addiction. When preparing to recruit participants for it, Mason said she worried she was “throwing a party that no one wanted to attend.”
The response surprised her.
“I've been doing alcohol research for a long time, and I got more people seeking treatment for cannabis than I did for alcohol,” she said.
About one-third of those don't use anything but cannabis, she said. And there were two predominant age groups, college-aged and people in their mid-50s, she said.
Southern California is a great location for the study, because there is confusion about the drug, she said. Medical marijuana, though illegal under federal law, is legal in the state.
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