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Study: Nicotine Changes Marijuana’s Effect On Brain

New research is changing the way that science evaluates marijuana’s effects on the brain. Until now, marijuana research tended to neglect tobacco users from the research studies.  However, a study just completed at the Cognitive Neuroscience of Addictive Behaviors at the Center for BrainHealth at The University of Texas at Dallas may change all that.  New results demonstrate significant differences between the brains of those who use both cannabis and tobacco and those who only smoke cannabis.

“Approximately 70% of individuals who use marijuana also use tobacco,” according to Francesca Filbey, Ph.D., the study’s principal investigator and Director of Cognitive Neuroscience of Addictive Behaviors at the Center for BrainHealth. “Our findings exemplify why the effects of marijuana on the brain may not generalize to the vast majority of the marijuana using population, because most studies do not account for tobacco use. This study is one of the first to tease apart the unique effects of each substance on the brain as well as their combined effects.”

The hippocampus is that part of the brain associated with learning and memory. It tends to be smaller in marijuana smokers compared to non-using control subjects. In non-users, the size of the hippocampus has a direct relationship to memory: the smaller the hippocampus, the worse the memory function of the test subject. So far so good, however users who smoked marijuana and tobacco together demonstrated an inverse relationship between hippocampus size and memory. In their case, the smaller the hippocampus, the better for their memory and learning functions. The role of nicotine in the relationship was directly proportional to hippocampal size. The more tobacco was smoked alongside marijuana, the smaller the hippocampul volume and better the memory performance. Most interestingly, there were no significant  associations between hippocampul size in individuals who only use tobacco or only use marijuana on its’ own.

Scientists have always been aware of the physiological affects of tobacco and marijuana but now they are becoming interested in the compound interactions between the two. For now, the study may offer hope for users who fear their marijuana use has done permanent or irreparable damage to their memories. Don’t throw in the towel or give up hope just yet!

Gladstones Clinic has a specialist cannabis detox and cannabis rehab programme that successfully empowers clients to break their addiction to cannabis.


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