Does The Bad Outweigh The Good With Longterm Cannabis Use? Effects On Brain Leave It Up For Debate

LANCASTER, England — “Because I Got High,” Afroman’s tongue-in-cheek yet cautionary song about overuse of cannabis is almost twenty years old.

The classic hip-hop track begins with the protagonist failing to clean his room “because he got high” and goes on to detail an increasingly serious series of forgotten tasks, culminating with the rueful  “I messed up my entire life because I got high.” Decades before, when Cheech and Chong trod similar ground with their spaced out skits, they were already riffing on a cliché.

No doubt the forgetful stoner is a classic stereotype. But is this well-known side effect of weed so saturated in the culture that its seriousness is underappreciated by a growingly pot-friendly public?

Though anecdotal evidence of cannabis’s deleterious effects on memory abounds, researchers say they are only just starting to gain a scientific understanding of the issue.

Neil Dawson, a researcher from Lancaster University, is one of the authors of a new study that is helping to shed light on the complex relationship between cannabinoids, memory, and other neurological function.  Along with colleagues, Dawson studied the effects of the cannabinoid drug WIN 55,212-2 on mice and found the drug caused problems in the way areas of the brain associated with learning and memory communicate with each other.

“This work offers valuable new insight into the way in which long-term cannabinoid exposure negatively impacts on the brain,” Dawson says in a press release on the study. “Understanding these mechanisms is central to understanding how long-term cannabinoid exposure increases the risk of developing mental health issues and memory problems.”

With the number of recreational and medical users of cannabis and similar drugs rising, the researchers say their work isn’t aimed at cutting people off from the often beneficial treatments, but instead understanding it and better managing the downsides.

“Cannabis-based therapies can be very effective at treating the symptoms of chronic diseases such as epilepsy and multiple sclerosis, and dramatically increase the quality of life for people living with these conditions,” Dawson notes. “We need to understand the side effects that these people may experience so that we can develop new interventions to minimize these side effects.”

In the paper the authors note earlier research has shown regular cannabis use, “generally defined as daily or almost‐daily use over a prolonged period of time” is associated with cognitive dysfunction and a higher risk of schizophrenia spectrum disorders, acute psychosis, mania, and an amotivational syndrome (the “syndrome” illuminated in the Afroman song).

They also note that earlier human MRI studies have shown “chronic cannabis users display significant alterations in functional connectivity in brain networks relevant to self‐awareness, working memory, and recognition memory, which may be linked with functional differences in structures of the medial temporal lobe and prefrontal cortex.”

The problem with these previous studies, Dawson and colleagues note, is that they don’t account for other variables affecting the human subjects — such as lifestyle and other drug use. This, they say, is why their highly controlled study on mice is yielding valuable new information.

“Importantly, our work clearly shows that prolonged cannabinoid intake, when not used for medical reasons, does have a negative impact in brain function and memory. It is important to understand that the same medicine may re-establish an equilibrium under certain diseased conditions, such as in epilepsy or MS, but could cause marked imbalances in healthy individuals,” says Ana Sebastiao, lead researcher at the University of Lisbon. “As for all medicines, cannabinoid based therapies have not only beneficial disease-related actions, but also negative side effects. It is for the medical doctor to weight the advantages of the therapy, taking into consideration quality of life and diseases progression, against the potential side effects.”

It is worth noting that the cannabinoid drug used in the experiments, WIN 55,212-2, has very similar effects to THC (one of the cannabinoids in weed mainly responsible for the “high”.) But, WIN 55,212-2 has an “entirely different chemical structure.” Accordingly, the researchers were careful to not entirely conflate the terms in their writing.

The full research paper was published in the Journal of Neurochemistry.

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