The Connection Between Marijuana & Dopamine

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Any marijuana smoker knows that the fun begins when dopamine is released, and we start having intense feelings of euphoria. The THC in marijuana disguises itself as anandamide (the so-called bliss molecule) which results in the blocking of inhibitory neurotransmitter gateways. With no inhibitory neurotransmitters blocking the dopamine gateways, a lot more dopamine than normal is left floating around in our brain, and this is what results in feelings of intense pleasure.

So what could be wrong with something that gives feelings of euphoria? Well, this is only the short-term effect, and new research has found something rather disturbing. Studies suggest that heavy, long-term use of marijuana could, in fact, reduce the levels of dopamine. Low levels of dopamine could lead to memory, concentration, and problem-solving deficits. On a more serious note, low levels are also associated with medical issues like fatigue, depression and mood changes. Given that in the United States, an estimated 78 million people have tried marijuana, this news is of great concern! It’s also important to note that a national survey done in 2014 found that of the 9.5% of adults who admitted that they use weed, a third of those reported on marijuana addiction symptoms.

What Is Dopamine?

Do you know what drug addiction and Parkinson’s disease have in common? They both have improper levels of dopamine. So what is dopamine? This is the chemical that acts as the messenger between brain cells. It’s vital for many of our daily behaviors and plays a role in how we learn, what we eat and even whether we become addicted to drugs.

The chemical messengers that are found in different parts of the brain are known as neurotransmitters. The neurotransmitter is the part of the brain that is responsible for sending signals from the central nervous system, and it’s what allows information to be passed from one neuron to the next. The ventral tegmental area and the substantia nigra are the two main areas of the brain that produce dopamine. Although the combined area of these two parts of the brain is small; less than the size of a post stamp, they produce the dopamine which ultimately relays the signals that travel through the brain.

The problem occurs when the brain cells that produce the dopamine die off. For instance, the lack of dopamine is what is thought to be linked to the Parkinson’s disease and drug addiction. This is why many Parkinson’s patients take medication that increases their dopamine levels.

How Are Marijuana & Dopamine Linked?

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Dopamine is the brain chemical that is linked to pleasure and reward, while the dopamine-releasing system is associated with addiction. Many behaviors that are considered to be addictive such as food, gambling, sex and drug use, activate the dopamine reward pathway. Drugs, including opioids, cocaine, alcohol, and marijuana all increase dopamine levels in the brain.

Marijuana indirectly increases dopamine. Rather than acting directly on the dopamine neurons, the cannabinoids found in marijuana act on the endocannabinoid system (ECS). Cannabinoid receptors can be found in many areas of the brain that have dopamine neurons, but dopamine neurons don’t have any cannabinoid receptors. Instead, GABA neurons which do have cannabinoid receptors inhibit the dopamine neurons in the reward pathway and when suppressed, the dopamine production increases.

It’s not just chemicals in marijuana that affect dopamine production. GABA is naturally inhabited by many other cannabinoids that are produced in the brain. The action of endocannabinoids (which are natural cannabinoids) are thought to play a vital role in releasing dopamine for day-to-day functions. A study done in 2013 by Dubreucq et al. discovered that mice that were born with no cannabinoid receptors used their exercise wheels up to 30% less often than healthy mice.

Marijuana is Awesome For Dopamine Production in the Short-Term

THC is possibly the most effective ingredient found in marijuana. Almost immediately after smoking weed, the THC exits the lungs and enters the bloodstream. It then moves towards the brain and meddles with the cannabinoid receptors. These are the receptors that control memory, pleasure, concentration and learning, among other things. This means that an individual will feel high as soon as THC is exposed to the body. This is the short-term effect of using marijuana. Studies have found that THC is significantly more effective than CBD when it comes to the positive short-term impact on dopamine.

An author by the name of French conducted two separate studies on rats to determine the difference between the effects THC and CBD have on dopamine. The first study used THC and discovered that it stimulated dopamine neurons in the midbrain. A similar study was then done using CBD which found that there was no evidence of cannabidiol increasing the dopamine in reward pathways. In essence, the effects of THC on dopamine is the reason you feel so good after you smoke. However, new research has suggested that in the long-term, marijuana usage can cause dopamine damage.

Does Marijuana Cause a Long-Term Reduction in Dopamine?

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A 2016 study, published in Molecular Psychiatry, “Deficits in Striatal Dopamine Release in Cannabis Dependence (link is external)” found that severe marijuana dependence is associated with a reduced release of dopamine within the striatum. The striatum is a part of the brain involved in working attention, memory, and impulsive behavior. Researchers believe that a reduction in dopamine release within the striatum could be linked to the emotional withdrawal and the inattention that was observed in marijuana-dependent study participants.
Interestingly though, a different study conducted by Professor Oliver Howes in 2016 concluded that it is the THC that produces potentially long-term effects on the dopamine system and not marijuana itself. The study was unable to pinpoint the direct cause of the link between heavy, long-term marijuana use and depression, anxiety, and schizophrenia. They then reviewed numerous studies that were done on how THC affects the brain, and that’s when they discovered that it’s the THC exposure that produces long-term effects on dopamine.

This is why long-term marijuana-users are thought to be at a greater risk of suffering mental health problems. Howe’s and his team have stated that existing gaps in marijuana research are of great concern. Specifically with regards to the lack of research into what happens to our dopamine system when we stop using marijuana. It’s clear that further research needs to be done into the connection between marijuana and dopamine.

Final Thoughts

While there’s no reason to get yourself worked up on the findings that long-term smoking could affect our dopamine system, it’s certainly something to think about. For heavy smokers of course. Here at MarijuanaBreak we always advocate smoking responsibly, so it’s important to know the ins and the outs of marijuana.

Having said that, a lot more research needs to be done on this subject before any of these findings can be treated as 100% factual. At present, all findings have come from studies that were done on animals which are useless since they take place over a few weeks rather than years. For now, we can sit back and wait to see what else researches have to say about the link between marijuana and dopamine.

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