Put down the joint, Potheads, it may be doing something funky to your brain. 

For years, there has been ongoing debate as to whether or not marijuana usage can lead to a pot addiction. 

Just in time for 4/20 (aka the National Weed Holiday), new evidence from Columbia University suggests that cannabis usage causes similar dopamine releases to cocaine and heroin addictions. 

Dr. Anissa Abi-Dargham, professor of psychiatry at Columbia University Medical Center stated, "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."

The study was conducted using 11 adults, aged 21-40, who were "severely dependent" on cannabis. 

On average, these subjects began using marijuana at 16, and became dependent on it by 20, and have been dependent on the drug for the last seven years, smoking at least once a day for the last month. 

The control group consisted of 12 healthy, non-users. 

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The study used position emission tomography (PET), a type of test consisting of a camera and a tracer radioactive chemical that are used in tandem to measure activity in the body, in this case, dopamine levels. 

The marijuana users remained at the hospital for a week of abstinence to eliminate acute effects of the drug. 

Compared to the control group, the drug users were found to have a "significantly lower dopamine release in the striatum, including subregions involved in associative and sensorimotor learning, and in the globus pallidus."

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So what does that mean? In short, and in terms much easier to follow, long-term users of marijuana may have negative issues of their dopaminergic system, which affects pleasure, motivation, cognition, and even movement. 

Though this might seem like propaganda fodder for anti-marijuana groups, the study (at least on the surface) seems to be funded and completed by unbiased groups, merely researching the differences in dopamine levels between cannabis users and other addictions. 

We're not telling anyone to drop the joint for good, but this evidence shows that it might be time to start weening back on heavy use. 

 Check out These Incredible Pizza Boxes You Can Smoke Weed With.