Study: Chronic Cannabis Use May Negatively Affect Memory

 In Naturopathic News

Node Smith, ND

Researchers are beginning to conclude that long-term use of cannabis, or cannabis derived drugs, impairs memory.1 Both recreational users, as well as those using the drug/herb for its therapeutic effects on epilepsy, multiple sclerosis, chronic pain, and other conditions may be affected.

Long-term use of cannabis or cannabis derived drugs impairs memory

The study was conducted on mice, and found that exposure to the drug over long periods of time resulted in significant memory dysfunction to the point where animals were unable to differentiate between novel and familiar objects.

Data lacking regarding negative side effects of long-term cannabinoid use

There has been a historical lack of data regarding the negative side effects of long-term use of cannabinoid agents, though it is becoming clear that regular, heavy use does increase the risk of experiencing mental health disorders like psychosis and schizophrenia. It is generally acknowledged that cannabis use does affect memory, though these effects are considered acute and transitory by many users. This study shows that there may be long-term memory impairment, which has largely been overlooked, or not understood.

Cannabinoid drug WIN 55,212-2

As more individuals are using the drug/herb, because of its legalization in many states and countries, and more potent varieties and products are becoming available, it is important that the negative side effects are clearly known.

The study specifically looked at the cannabinoid drug WIN 55,212-2 in mice and saw 3 primary side effects related to memory:

  • Chronic use/exposure diminished learning ability and memory
  • Neuroimaging showed impairment of key areas of the brain necessary for memory and learning.
  • Chronic use/exposure inhibited brain regions involved in learning and memory to communicate with each other.

Cannabis study highlights

The study highlights that cannabis, and cannabinoid drug agents have a negative side effect profile, just like any other drug. These substances can be extremely effective in treating many conditions, though they are not completely benign. Use of them, as with any therapeutic agent must take into account the full range of physiological effects that may occur, both over the short-term and long-term.


  1. Mouro FM, Ribeiro JA, Sebastião AM, Dawson N. Chronic, intermittent treatment with a cannabinoid receptor agonist impairs recognition memory and brain network functional connectivity. J Neurochem. 2018
Photo by Connor Limbocker on Unsplash

Node Smith, ND, is a naturopathic physician in Portland, OR and associate editor for NDNR. He has been instrumental in maintaining a firm connection to the philosophy and heritage of naturopathic medicine among the next generation of docs. He helped found the first multi-generational experiential retreat, which brings elders, alumni, and students together for a weekend camp-out where naturopathic medicine and medical philosophy are experienced in nature. Four years ago he helped found the non-profit, Association for Naturopathic ReVitalization (ANR), for which he serves as the board chairman. ANR has a mission to inspire health practitioners to embody the naturopathic principles through experiential education. Node also has a firm belief that the next era of naturopathic medicine will see a resurgence of in-patient facilities which use fasting, earthing, hydrotherapy and homeopathy to bring people back from chronic diseases of modern living; he is involved in numerous conversations and projects to bring about this vision.

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