The surgeon general announces that marijuana does, in fact, have an affect on brain development

How much do we know about marijuana and the effects that are caused in the brain? Bonus: the surgeon general’s statement

Are we aware of the affects of marijuana? Let’s start with how it is composed. Marijuana refers to dried leaves, flowers, stems, and seeds of the Cannabis sativa or Cannabis indica plant, a plant that contains delta-9-tetrahydrocannabinol (THC), a chemical that impacts mental health, educational achievement, and raises the risks of addiction… among other negative consequences. 

According to the U.S. Department of Health & Human Services, today’s marijuana is much stronger than previous versions. The THC concentration has increased three-fold between 1995 and 2014 (4% and 12% respectively). Marijuana available in dispensaries in some states has average concentrations of THC between 17.7% and 23.2%. Concentrated products, commonly known as dabs or waxes, are far more widely available to recreational users today and may contain between 23.7% and 75.9% THC THC concentration has increased three-fold between 1995 and 2014 (4% and 12% respectively)

It’s no secret that Marijuana is also one of the easiest substances to find. More than 20% of Americans have voted to legalize recreational use. Today, marijuana is legal for recreational purposes in 11 states as well as Washington, DC. Other states have legalized it for medical use. It’s also possible to extract concentrates from the cannabis plant, therefore it can now be eaten, drank, smoked, and vaped! 

There’s still a lot to discover surrounding this controversial substance. For now, the best we can do is offer some information regarding short and long term effects. 

Marijuana short term effects

When a person smokes marijuana, THC goes from the lungs to the bloodstream. From there, it ends up reaching the brain and other organs. THC connects to a brain nerve cell receptor. The “high” of marijuana is due to the effects of THC on nerve cells that control sensory perception and pleasure.

  • Altered senses (for example, colors look brighter)
  • Lack of coordination
  • Alteration of time perception
  • Mood changes
  • Limitation of body mobility
  • Difficulty thinking and solving problems
  • Memory weakening
  • Hallucinations (when consumed in large doses)
  • Delirium (when consumed in large doses)
  • Psychosis (when consumed in large doses)

Marijuana long term effects

According to a study in New Zealand conducted in part by researchers at Duke University showed that people who started smoking a lot of marijuana in adolescence and continued to consume it lost, on average, 8 points of IQ between 13 and 38 years of age. age. People who abandoned marijuana as adults did not fully recover the mental capacity they had lost. Those who started smoking pot in adulthood did not show a noticeable decrease in IQ.

The amount of THC found in marijuana has been steadily increasing in recent decades. For a person who has just started using the drug, this may mean that they are exposed to higher THC levels and are more likely to suffer an adverse reaction. Higher THC levels could explain the increase in visits to emergency rooms related to marijuana use. Also being chronically exposed to THC can accelerate the loss of neurons in the age-related hippocampus. In one study, rats that had been exposed to THC daily for 8 months (approximately 30 percent of their life) showed a loss in neural cells (between 11 and 12 months of age) equal to that seen in animals twice the age that have not been exposed to THC.

  • Changes in the brain
  • Fertility issues
  • Respiratory problems.
  • Immune system problems
  • Emotional problems.


As people that use marijuana get older, the degradation of memory occurs, and that’s because THC alters how information is processed in the hippocampus, an area of the brain responsible for creating memories, as a result, helping to decrease the ability to learn new information.

What the surgeon general says about marijuana effects on the developing brain

The human brain continues to develop from before birth into the mid-20s and is vulnerable to the effects of addictive substances. Frequent marijuana use during adolescence is associated with changes in the areas of the brain involved in attention, memory, decision-making, and motivation. Deficits in attention and memory have been detected in marijuana-using teens even after a month of abstinence. Marijuana can also impair learning in adolescents. Chronic use is linked to declines in IQ, school performance that jeopardizes professional and social achievements, and life satisfaction. Regular use of marijuana in adolescence is linked to increased rates of school absence and drop-out, as well as suicide attempts. 

At the end of the day, there is evidence to show that marijuana could affect brain development in a negative way. If you feel that you or a loved one is developing a substance dependence we’re here to answer any questions you may have and help in any way we can.