The National Institute of Health is funding a $4 million, four-year study of the long-term effects of marijuana. Dr. Barbara Mason, director of Scripp's Laboratory of Clinical Psychopharmacology, will lead the study which involves three other labs.

About one in nine people who try marijuana become dependent, according to research form the University of Michigan. While alcohol clears the human body within hours, marijuana lingers and can be detected up to 30 days after use. Some symptoms of marijuana withdrawal are sleep disturbances, anxiety, and irritability.

The new research will investigate whether marijuana use affects learning, judgment, and self-control. Dr. Mason and others will also study whether marijuana affects young people differently than adults.

"The thing that troubles a lot of us is that marijuana has an appeal to younger people," said Dr. Reese Jones, a professor of psychiatry at the University of San Francisco. "In recent time we have learned that the adolescent brain is so different in many ways than the final adult version. There is a lot of reason to think that all these issues may be a bigger deal for young people."

NorthStar Center is a residential treatment center for young adults in recovery from substance abuse. Learn more about their program that combines therapy with academics at NorthStarCenter.com.

Labels: effects, long_term_drug_use, marijuana