Neuroimaging, Cannabis, and Brain Performance & Function

I think pot should be legal. I don’t smoke it, but I like the smell of it.

— Andy Warhol

Cannabis contains various molecules which bind to receptors in the brain, aptly called “cannabinoid receptors”. Familiar ligands (which bind to those receptors) include THC (tetrahydrocannabinol) and CBD (cannabidiol), binding to receptors such as the CB1 and CB2 receptors with various downstream functions on the brain. The primary neurotransmitter involved in innate (endogenous) cannabinoid activity is “anandamide”, a unique “fatty acid neurotransmitter” whose name means “joy”, “bliss” or “delight” in Sanskrit and related ancient tongues. This neurotransmitter system has only relatively recently been investigated in greater detail, and the basic biology is fairly well worked out (e.g. Kovacovic & Somanathan, 2014), improving understanding of therapeutic, recreational and adverse effects of different cannabinoids, and paving the way for novel synthetic drug development.

Increasing interest in the therapeutic and recreational use of cannabis demands greater understanding of the effects of cannabis on the brain and behavior. Because of the controversial and politicized nature of marijuana in societal discourse, strong beliefs about cannabis obstruct our capacity to have a reasoned conversation about potential pros and cons of cannabis use, and have impeded research initiatives. Nevertheless, many states have permitted medical and recreational use of cannabis preparations, while the federal government is swinging back toward more restrictive policies.

The jury is out

Cannabis advocates, on the other hand, may paint too rosy a picture of the benefits of cannabis preparations, downplaying or dismissing relevant information about the hazards of cannabis in specific populations at risk for certain mental disorders, the risks of cannabis use disorders and the negative effects of cannabis on certain cognitive processes accompanied by potentially deleterious, and even dangerous, effects on decision-making and behavior.

For instance, while cannabis preparations have been shown to be useful for pain management and functional improvement in various conditions, improving quality of life, cannabis may also cause errors in…