Excessive Cannabis Smoking Reduces Dopamine Levels, Study Finds

Researchers at Columbia University Medical Center, New York, have discovered that heavy cannabis use has the same effect on your brain’s dopamine system as chronic cocaine or heroin use: i.e. excessive smoking of cannabis, just like cocaine and heroin addiction, decreases dopamine levels in the brain and could lead to memory, attention, and problem-solving deficits.

Heavy cannabis use associated with reduced dopamine release in brain https://t.co/ooNlj5oLpT pic.twitter.com/wOQmRpeOAJ

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In the study, titled “Deficits in Striatal Dopamine Release in Cannabis Dependence,” published online on March 22 in Molecular Psychiatry, an international team of researchers used positron emission tomography (PET) to track a radiolabeled molecule that binds to dopamine receptors in the brain — to measure dopamine release in the striatum and its subregions, as well as in several brain regions outside the striatum, including the thalamus, midbrain, and globus pallidus.

The PET scans found that the cannabis users had significantly lower dopamine release in the striatum, including subregions involved in associative and sensorimotor learning, and in the globus pallidus. The authors stated:

“Most drugs of abuse lead to a general blunting of dopamine release in the chronic phase of dependence, which contributes to poor outcome. To test whether cannabis dependence is associated with a similar dopaminergic deficit, we examined striatal and extrastriatal dopamine release in severely cannabis-dependent participants, free of any comorbid conditions, including nicotine use… In conclusion, this study provides evidence that severe cannabis dependence—without the confounds of any comorbidity—is associated with a deficit in striatal dopamine release. This deficit extends to other extrastriatal areas and predicts subclinical psychopathology.”

Reefer Madness!
"Funding for this study was provided by the National Institute on Drug Abuse"

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However, the researchers also noted that the result does not indicate that excessive smoking of marijuana directly caused the participants’ decreased dopamine levels; other pre-existing health conditions could have also contributed to the findings, they added. Lead author Dr. Anissa Abi-Dargham, professor of psychiatry (in radiology) at Columbia University Medical Center, explained:


“We don’t know whether decreased dopamine was a preexisting condition or the result of heavy cannabis use, but the bottom line is that long-term, heavy cannabis use may impair the dopaminergic system, which could have a variety of negative effects on learning and behavior… In light of the more widespread acceptance and use of marijuana, especially by young people, we believe it is important to look more closely at the potentially addictive effects of cannabis on key regions of the brain.”

According to Clinical Psychologist Dr. Joseph Carver, low levels of dopamine in the brain can produce motor-control problems; lead to Parkinson’s disease, depression and anxiety; and affect the portions of the brain that impact thinking, impairing the ability to concentrate and focus.

In 2013, scientists at Imperial College London, University College London and King’s College London conducted the PET scans on the brains of 38 people – 19 regular cannabis users and 19 non-users – and found low dopamine levels in chronic cannabis users. Dr Michael Bloomfield of Imperial College London, noted:

“Dopamine is involved in telling the brain when something exciting is about to happen – be it sex, drugs or rock ‘n roll. Our findings explain why cannabis has a tendency to make people sit around doing nothing. The results weren’t what we expected but tie in with previous research on addiction which has found substance abusers have altered dopamine systems.

“Although we only looked at cannabis users who have had psychotic-like experiences while using the drug, we think the findings would apply to cannabis users in general since we didn’t see a stronger effect in the subjects who have more psychotic-like symptoms.  It could also explain the “amotivational syndrome” which has been described in cannabis users but whether such a syndrome exists is controversial.”

In 2015, the US National Cancer Institute admitted that marijuana kills cancer cells; however, excess of everything is bad, and cannabis – a non-toxic substance – is no exception. What do you think? Please share your thoughts in the comment section below.

#Marijuana Drastically Shrinks Aggressive Form Of Brain #Cancer

Study https://t.co/oiviegssGl #MME #cannabis #cbd pic.twitter.com/lLHeQ12QeH

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