There’s more than meets the eye when it comes to the neurological and physiological effects of cannabis. Heightened senses, mild euphoria, altered perception, and changes in motor coordination may be cannabis’ most noticeable characteristics, but in reality, its use triggers many small-scale changes in both the brain and the body.
These effects can be grouped as “short-term” and “long-term”, with short-term effects wearing off within a relatively brief period after use, and long-term effects occurring with regular exposure over a prolonged period of time.
Cannabis education is one of the keys to responsible use. It’s important for consumers to understand how the narcotic affects them so that they can make more informed choices.
It’s also a good idea to stay abreast on current research into the risks and long-term effects of cannabis, so users can more accurately determine whether or not they want to continue to partake.
Short-Term and Long-Term Cannabis Effects on the Brain
Tetrahydrocannabinol, or THC, is the psychoactive ingredient in cannabis, and it is this substance that produces the high users get after ingesting the plant. The exact nature of these effects often vary from person to person. They can also be affected by the user’s mindset and the circumstances under which the cannabis is ingested (a phenomenon commonly called “set and setting”).
Common ingestion methods include combustion (smoking), vaporization (vaping), and eating or drinking cannabis derivatives (edibles). While different ingestion methods can produce different user experiences, they all work on the brain in similar ways.
A Rise in Dopamine - A Short Term Effect
The main neurochemical change that takes place after using cannabis is an increase in the amount of dopamine produced by the brain. Dopamine is a neurotransmitter with many important regulatory functions. It also has noted effects on mood, with higher dopamine levels being associated with better moods. This is because dopamine stimulates the brain’s so-called “pleasure centres”, which are the aspects of brain chemistry that control feelings of pleasurable reward.
Cannabis’s dopamine stimulation properties wear off within a few hours of ingestion. This usually makes the user feel tired, though some people also report heightened feelings of depression. This is thought to be due to the diminishing presence of dopamine in the brain, as dopamine production declines back to normal levels as the body processes and eliminates THC in the bloodstream.
Cannabis is also thought to affect other regions of the brain, including the basal ganglia and cerebellum. These brain centres play important roles in reflexes, reaction times, balance, and motor coordination. Thus, it is recommended that cannabis users avoid driving or operating machinery while they are under its effects.
Reducing Seizures In Adulthood - Cannabis in the Long-Haul
Long-term cannabis effects on the brain have been the study of much scientific inquiry, and there is significant debate within the research community with regard to the results of recent studies.
One report that received significant media attention was a 2014 study performed at Northwestern University, which looked at the developmental consequences of cannabis use during adolescence.
The 2014 Northwestern study found that users who began taking cannabis regularly during their teen years had decreased densities of neural fibers in certain parts of the brain, and hippocampus regions that were smaller than normal. The hippocampus is heavily involved in memory formation, short-term recall, and long-term recall. However, users who did not begin taking cannabis regularly until they were over the age of 21 did not show these symptoms.
Thus, the current scientific consensus is that it is likely safer for people not to use cannabis on a regular basis until their brains are fully formed in early adulthood.
Beyond these possible risks, cannabis may also have some positive effects on the brain. Research dating back to 2003 shows that cannabis can reduce the frequency and severity of epileptic seizures, since their active chemicals bind with brain cells to increase relaxation and reduce excitability. Cannabis has also been shown to calm down the hyperactive brain functions that cause more severe forms of seizure-causing medical syndromes.
Short-Term and Long-Term Cannabis Effects on the Body
One of the most immediate cannabis effects on the body is an increase in heart rate of 20 to 50 beats per minute, which can last for several hours after ingestion. While this is rarely dangerous, users with a history of circulatory system problems should be aware of this.
In addition, cannabis is noted for its pain relief and anti-nausea properties, which can take effect fairly quickly after ingestion.
It is also notorious for stimulating appetite, something many users refer to as “getting the munchies”. This can actually be highly beneficial to patients with diseases that reduce appetite, and to patients who treat underlying medical conditions with drugs that have appetite-reducing side effects.
Sushi craving, anyone?
Research has revealed numerous potential long-term cannabis effects on the body, both positive and negative. These include:
- Decreased pressure in the eyes, which can prevent or treat glaucoma
- Increases in beneficial bacteria activity in the digestive system
- Improved sleep
- Possible stimulation of the metabolism
- Possible reductions in immune system function
The current scientific consensus is that while using cannabis may carry some significant risks, especially for younger people, it also offers benefits. These potential risks and benefits should be carefully weighed by anyone who uses cannabis on a regular basis, or is interested in trying it.
For more on this topic, check out ASAP Science's short video about your brain on cannabis.