Marijuana Shown to Reduce Dopamine in the Brain

Dopamine is a transmitter in the brain that is important for movement, thinking and memory, but it is also known as the “reward chemical” for its role in pleasure. One recent study reveals that heavy marijuana use could compromise the dopamine system. Many people consider marijuana non-addictive, but one recent study reveals that heavy marijuana use may compromise the dopamine system—just like heroin and cocaine. This wouldn’t justify its position as a schedule 1, but it serves as a reminder that even non-lethal drugs can negatively affect our brains.

Marijuana and Dopamine

The study was published in the journal Molecular Psychiatry. Until then, such data regarding cannabis was scarce. The rapidly changing legal status of marijuana, a relatively new social movement, makes data like this especially important. To test the effects of marijuana dependence, researchers observed 11 marijuana-dependent adults aged 21-40, who on average began using around age 16, and compared them with a control of 12 non-dependent individuals.

Using positron emission tomography (PET) scans, researchers were able to track a radiotracing molecule that binds to the brain’s dopamine receptors. The team could also track dopamine release in other brain regions, including the thalamus, the midbrain, and the globus pallidus. Throughout the week-long study, the subjects stayed in the hospital, where they monitored to make sure they didn’t use any pot.

Compared with the control group, the marijuana users’ striatum showed lower dopamine release. This extended to the subregions, where associative and sensorimotor learning are regulated.

No link was found between dopamine release in the striatum and cognitive performance—learning, working memory, etc. However, it was noted that among all subjects, those who had lower dopamine release performed worse on both tasks.

Addiction and Dopamine

It’s unclear whether decreased dopamine is a preexisting condition or the result of heavy cannabis use. The bottom line: Long-term, heavy usage can impair the dopaminergic system, and this can have a variety of negative effects on learning, behavior, and other complex behavioral adaptations. Lowered dopamine release is linked with inattention, poor working memory and probabilistic category learning performance. There’s even a term for this phenomenon: “amotivation syndrome.”

Just because the legality of cannabis is increasing doesn’t make recreational use any less harmful or risky. It can make you feel happy and giddy in the moment; its overall effects on happiness and quality of life are gloom.


Fortunately, those effects are reversible. For help with moving on from a pot habit, contact Hired Power today: xxx-xxx-xxxx