Cannabis use has long been associated with memory loss.
But until now, this notion was largely anecdotal. As researchers begin to look into cannabis and the effect that it has on human health, they’re beginning to better understand the effect it has on the human brain – and whether cannabis really does impair memory.
Memory is divided into both short-term and long-term memory. Short-term memory is where immediate events are temporarily stored, whereas long-term memory is where information is stored indefinitely.
Current evidence shows that cannabis intoxication may temporarily alter or distort short-term memory processing.
This seems to be caused by compounds in cannabis that disrupt neural signaling when binding to receptors responsible for memory in the brain.
Interrupted short-term memory can indeed impact on learning, and may also cause loss of interest or problems with concentration.
However, early research also shows that cannabis could have a positive impact on neurodegenerative diseases that affect memory, such as Alzheimer’s, Huntington Chorea, and epilepsy.
In mainly animal studies, when researchers used components found in cannabis, they found it could slow or even prevent the advance of these diseases – essentially through the creation of neurons.
These apparently paradoxical effects from the same drug are best explained by two chemicals found in cannabis. Namely delta 9-tetrahydrocannabinol (THC) and cannabinoids (CBD).
We all have naturally occurring cannabinoid receptors in our brains. THC is able to effectively bind to these receptors, creating euphoric effects.
However CBD can interfere with this binding process, which dampens the feeling of euphoria.
Different ratios of these two chemicals are found in various types of cannabis.
Consuming a cannabis product with THC but no CBD increases the risk of developing mental health problems, such as psychosis. However, CBD could actually be used to treat psychosis.
Cannabis with higher levels of THC and lower, or negligible, amounts of CBD appear to have a detrimental effect on short-term memory, particularly in adolescents.
The main problem is their ability to retain and recall information. Fortunately this is not permanent.
But these recent discoveries about the role of THC and CBD in cannabis show that we can no longer simply say cannabis itself causes psychosis, or is detrimental to memory.
Rather, it might be the type of cannabis, and the compounds it contains, that may have specific risks or benefits.