Meth and Weed

Methamphetamine and marijuana are commonly used together. While some research suggests marijuana may help protect the brain from meth damage, the evidence is inconclusive. In adolescents, combining the drugs has been shown to cause serious, possibly permanent, brain damage.
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Researchers have not reached a consensus about the consequences of combining meth and marijuana. While some studies indicate marijuana may protect the adult brain from meth damage, that does not seem to apply to adolescents’ brains.

Although many people intentionally use meth and weed at the same time, reports of meth-laced marijuana have occasionally appeared in the media. Some say such reports are overblown.

Why Do People Mix Meth and Weed?

People mix meth and weed for a variety of reasons.

Crystal meth is a potent stimulant that causes an intense rush of energy and long-lasting euphoria. But a meth high can also be an uncomfortable experience, provoking feelings of anxiety, paranoia and even psychosis.

Some people smoke pot while using crystal meth to try to take the edge off the high or ease the effects of a meth comedown. Others say it intensifies the high. Sometimes people use the two drugs together simply because they’re available.

Mixing the two drugs may provoke extremely different effects depending on the individual. While smoking weed dulls the meth high for some people, mixing the drugs increases anxiety and paranoia in others. Some people who’ve combined meth with pot have described experiencing a sudden increase in heart rate.

Others report that marijuana has no noticeable effects on their meth high.

Your Brain and Body on Meth

Repeated use of meth often leads to meth addiction — and the man-made drug ravages the body from head to toe.

Over time, a person using meth may exhibit skin sores, significant weight loss, severe dental problems, bizarre behavior and other signs of meth use.

Eventually, meth destroys parts of the brain. The long-term effects of meth use include a decline in thinking and motor skills and severe changes to the structure and function of parts of the brain associated with emotion and memory.

Mood disturbances, confusion and insomnia are common symptoms of chronic meth use, and some individuals develop symptoms of psychosis that can continue or recur for years after they’ve stopped using the drug.

Exactly what happens to the brain when meth is mixed with marijuana is not as well understood.

Can Weed Prevent Meth Brain Damage?

Some research indicates pot might partially protect the brain from meth-induced damage — at least in animals.

Meth injures the brain by stimulating the production of proteins and other chemicals that cause severe inflammation. But according to a 2014 study in the journal PLOS One, the active ingredient in marijuana, THC, may lessen production of at least two of these aggravating proteins.

In their small study on mice, researchers at the University of Cagliari in Italy observed reduced levels of inflammation in the brains of rodents who were given both meth and THC. The mice experienced these benefits regardless of whether they received the THC before or after being given methamphetamine.

Human studies on the subject have been inconclusive.

A 2004 study in the journal Drug and Alcohol Dependence, for example, found that heavy meth and marijuana users performed better on neurocognitive tests than people who just used methamphetamine.

But the authors of the study stopped short of declaring that marijuana had a protective effect on the brains of meth users. They concluded only that marijuana use does not appear to worsen brain damage from meth.

Teens Who Mix Meth and Weed

Even if marijuana has some protective effects on the brains of adult meth users, the same isn’t true for adolescents. In fact, several studies indicate that mixing crystal meth and marijuana can cause significant brain damage in teens and young adults.

A small 2013 study in the journal Behavioural Brain Research found that heavy use of weed and meth is toxic to developing brain cells and may contribute to the emergence of psychiatric symptoms in adolescents.

Those findings were bolstered by a 2015 study in the journal BMJ Open that found greater levels of brain dysfunction among teenagers who combined meth and weed than among those who used meth alone. In particular, the group that used both meth and weed performed more poorly in areas of verbal reasoning, verbal memory, planning and self-monitoring. The study noted that such deficits may be permanent.

According to at least one study, mixing weed and meth may also make young people more susceptible to drug abuse and addiction.

A 2012 study in the journal Developmental Neuroscience compared the brains of adolescents who abused meth, meth and weed, and no drugs at all. Those who used meth and marijuana in combination demonstrated changes in the brain consistent with intensified novelty-seeking — a personality trait associated with drug experimentation and chronic drug use.

Meth-Laced Weed

While scientists continue to sort out the combined effects of meth and marijuana, anecdotal media reports have claimed meth-laced marijuana is being sold on the streets.

In 2016, police in Bismarck, North Dakota, issued a warning to the public about marijuana possibly contaminated with fentanyl and meth after a town resident fell ill from taking two puffs of a joint. The man, who landed in the emergency room, tested positive for marijuana, meth and fentanyl.

The phenomenon has also been reported in Canada. In 2006, a 16-year-old drug dealer told CBC News in Saskatchewan that he would intentionally add small amounts of hard drugs, such as cocaine and meth, to pot. He said he wanted to get his customers to prefer his supply or become addicted so he’d make more money.

Some drug policy experts argue that reports of meth-laced weed are overblown. In a 2008 article published in the Harm Reduction Journal, Mark Haden, an adjunct professor at the University of British Columbia School of Public and Population Health, noted that no crystal meth-laced weed was ever seized by police despite warnings by the press about contaminated marijuana.

Medical Disclaimer: aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.

Amy Keller, RN, BSN
Content Writer,
As a former journalist and a registered nurse, Amy draws on her clinical experience, compassion and storytelling skills to provide insight into the disease of addiction and treatment options. Amy has completed the American Psychiatric Nurses Association’s course on Effective Treatments for Opioid Use Disorder and continuing education on Screening, Brief Intervention and Referral to Treatment (SBIRT). Amy is an advocate for patient- and family-centered care. She previously participated in Moffitt Cancer Center’s patient and family advisory program and was a speaker at the Institute of Patient-and Family-Centered Care’s 2015 national conference.

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