By Steven Reinberg 
 
 HealthDay Reporter 
 
 (HealthDay) 
 
 WEDNESDAY, Feb. 17, 2016 (HealthDay News) -- Pot smokers may be at significantly greater risk for developing an addiction to other drugs or alcohol, a new study suggests. 
 
 Researchers found that adult marijuana use was associated with greater likelihood of developing alcohol and drug use problems, including nicotine dependence, over three years of follow-up. But it was not associated with greater risk of developing a mood or anxiety disorder. 
 
 "This new finding raises the possibility that the recent rise in marijuana use may be contributing to the coincident rise in serious harms related to narcotics and other drugs of abuse," said lead researcher Dr. Mark Olfson. He is a professor of psychiatry at Columbia University Medical Center in New York City. 
 
 The results stem from a sampling of nearly 35,000 adults interviewed three years apart for the U.S. National Epidemiologic Survey on Alcohol and Related Conditions. Almost 1,300 of the adults used marijuana, the researchers found. 
 
 Two-thirds of marijuana users had some form of substance use disorder three years later compared to less than 20 percent of those who didn't use marijuana in the previous year, the study found. 
 
 "Those who used marijuana once or more a month had the highest rates of substance use disorders at follow-up (70.5 percent)," Olfson said. 
 
 Olfson cautioned that this study cannot prove that marijuana caused these addiction problems. But the possibility should be considered as more states consider marijuana legalization, he said. 
 
 "In the ongoing national debate concerning whether to legalize recreational marijuana, the public and legislators should take into consideration the potential for marijuana use to increase the risk of developing alcohol abuse and other serious drug problems," Olfson said. 
 
 Specifically, at the three-year follow-up, marijuana users were about six times more likely to have any substance use disorder; nearly three times as likely to have an alcohol disorder; and about 10 times as likely to report any marijuana use disorder. Marijuana users were also nearly twice as likely to report nicotine dependence, the findings showed. 
 
 "Compared with people who were not using marijuana, those who were using marijuana were more than 10 times as likely to have developed [any other] new drug use disorder three years later [13.9 percent versus 1.1 percent]," Olfson said. 
 
 One expert viewed the report -- published online Feb. 17 in the journal JAMA Psychiatry -- with skepticism. 
 
 "I am quite dubious of these findings," said Mitch Earleywine, a professor of psychology at the State University of New York at Albany. Earleywine is also a member of the advisory board of NORML, which promotes marijuana legalization. 
 
 The notion that marijuana leads to addiction to other drugs -- the "gateway" theory -- has been touted over the years, but Earleywine discounts it. "I am unable to see this association after 40 years of clinical experience," he said. 
 
 Marijuana may trigger those already predisposed to mental problems or addiction to go on to have these problems, but for many people marijuana does a lot of good, Earleywine said. 
 
 Going from marijuana to another drug "says more about the person than about marijuana," he said. 
 
 "There is very little to be concerned about with marijuana. There is more to be concerned about with alcohol or any of the other psychoactive drugs that the drug industry prescribes," Earleywine said. 
 
 More information 
 
 For more on marijuana, visit the U.S. National Institute on Drug Abuse. 

 Importance With rising rates of marijuana use in the general population and an increasing number of states legalizing recreational marijuana use and authorizing medical marijuana programs, there are renewed clinical and policy concerns regarding the mental health effects of cannabis use. 
 
 Objective To examine prospective associations between cannabis use and risk of mental health and substance use disorders in the general adult population. 
 
 Design, Setting, and Participants A nationally representative sample of US adults aged 18 years or older was interviewed 3 years apart in the National Epidemiologic Survey on Alcohol and Related Conditions (wave 1, 2001-2002; wave 2, 2004-2005). The primary analyses were limited to 34 653 respondents who were interviewed in both waves. Data analysis was conducted from March 15 to November 30, 2015. 
 
 Main Outcomes and Measures We used multiple regression and propensity score matching to estimate the strength of independent associations between cannabis use at wave 1 and incident and prevalent psychiatric disorders at wave 2. Psychiatric disorders were measured with a structured interview (Alcohol Use Disorder and Associated Disabilities Interview Schedule–DSM-IV). In both analyses, the same set of wave 1 confounders was used, including sociodemographic characteristics, family history of substance use disorder, disturbed family environment, childhood parental loss, low self-esteem, social deviance, education, recent trauma, past and present psychiatric disorders, and respondent’s history of divorce. 
 
 Results In the multiple regression analysis of 34 653 respondents (14 564 male [47.9% weighted]; mean [SD] age, 45.1 [17.3] years), cannabis use in wave 1 (2001-2002), which was reported by 1279 respondents, was significantly associated with substance use disorders in wave 2 (2004-2005) (any substance use disorder: odds ratio [OR], 6.2; 95% CI, 4.1-9.4; any alcohol use disorder: OR, 2.7; 95% CI, 1.9-3.8; any cannabis use disorder: OR, 9.5; 95% CI, 6.4-14.1; any other drug use disorder: OR, 2.6; 95% CI, 1.6-4.4; and nicotine dependence: OR, 1.7; 95% CI, 1.2-2.4), but not any mood disorder (OR, 1.1; 95% CI, 0.8-1.4) or anxiety disorder (OR, 0.9; 95% CI, 0.7-1.1). The same general pattern of results was observed in the multiple regression analyses of wave 2 prevalent psychiatric disorders and in the propensity score–matched analysis of incident and prevalent psychiatric disorders. 
 
 Conclusions and Relevance Within the general population, cannabis use is associated with an increased risk for several substance use disorders. Physicians and policy makers should take these associations of cannabis use under careful consideration.
– Lighting up a joint now could make you more likely to crack a bottle later—and have issues putting it down, or so suggests a pair of new studies. In the first, published in Drug and Alcohol Dependence, researchers say they've found that marijuana users seem to have an "increased vulnerability" to developing an alcohol use disorder (defined as alcohol abuse or dependence) as compared to their pot-free counterparts. They used data on 27,461 adults who took part in the National Epidemiologic Survey on Alcohol and Related Conditions and reported having no AUD in 2001 and 2002 (aka, "Wave 1"). Fast-forward three years to "Wave 2," and those who reported marijuana use originally were 5.4 times more likely to have an AUD, per the study. The second study, published in JAMA Psychiatry, made use of NESARC data as well, but a slightly broader slice: 34,653 adults. Its findings were broader as well: Those who used pot in Wave 1 were roughly six times more likely to have any kind of substance use disorder three years later; when it specifically came to an AUD, this study found they were 2.7 times more likely to have developed one (the reason for the discrepancy is unclear). Those researchers also looked at other drug use disorders and nicotine dependence; the likelihood was higher for pot smokers in both cases. But a psychology professor and legalization advocate tells HealthDay he's skeptical. As far as the pot-to-other-drugs "gateway" theory goes, "I am unable to see this association after 40 years of clinical experience." (Another study finds that teens who smoke pot don't get dumber as a result.)