PITTSBURGH, Dec. 4 (UPI) -- A 12-year University of Pittsburgh study challenges the long-held belief that marijuana is a "gateway" drug that eventually leads to substance abuse.
The researchers tracked 214 boys beginning at ages 10 to 12, all of whom eventually used either legal or illegal drugs.
When the boys reached age 22 they were categorized into three groups: those who used only alcohol or tobacco, those who started with alcohol and tobacco and then used marijuana -- gateway sequence -- and those who used marijuana prior to alcohol or tobacco -- reverse sequence.
Nearly one-quarter of the study population who used both legal and illegal drugs at some point -- 28 boys -- exhibited the reverse pattern of using marijuana prior to alcohol or tobacco, and those individuals were no more likely to develop a substance-use disorder than those who followed the traditional succession of alcohol and tobacco before illegal drugs, according to the study, published in the American Journal of Psychiatry.
"The gateway progression may be the most common pattern, but it's certainly not the only order of drug use," said lead author Ralph E. Tarter, professor of pharmaceutical sciences at the University of Pittsburgh School of Pharmacy. "In fact, the reverse pattern is just as accurate for predicting who might be at risk for developing a drug dependence disorder."
