The relationship between cannabis and the brain is a meaty subject. Identifying the various ways cannabis affects the brain is complicated, and we’ve only just begun to unravel many of the mysteries. Most perplexingly, there’s a lot of seemingly contradictory evidence out there.
On the one hand, we’re inundated with messages that cannabis impairs a user’s cognitive function — particularly short-term memory. On the other hand, we hear cannabis can act as a neuroprotectant, perhaps even preventing the onset of neurodegenerative diseases like Alzheimer’s.
How can this be? Cannabis is a diverse, complex plant comprised of hundreds of chemicals. And, two of its most prominent constituents — THC and CBD — affect us in significantly different ways. But, first, let’s start with an explanation of the endocannabinoid or ECS.
What is the Endocannabinoid System and Why is It Important?
The ECS, also known as “the body’s own cannabinoid system," is a group of cannabinoid receptors located in the brain and throughout the central nervous system (CNS) and peripheral nervous system (PNS). It plays a vital role in the regulation of mood, memory, physiology, pain sensation, appetite, and overall health. While the ECS performs numerous tasks, its primary goal is or the maintenance of a stable and healthy internal environment.
The discovery of the endocannabinoid system and associated receptors has played a significant role not just in our understanding of cannabis, but of human biology, health, and disease.
Scientists have identified the two primary cannabinoid receptors, CB1 and CB2:
- CB1 receptors can be found primarily in the brain and nervous system, but are also found in other organs and connective tissues. CB1 is the main receptor for THC, a phytocannabinoid ( meaning, “of the plant”); and, its twin, anandamide, one of the body’s naturally occurring cannabinoids which THC mirrors. The activation of CB1 receptors by THC is responsible for cannabis’ psychoactive effects.
- CB2 found predominantly in the immune system and associated structures, are responsible for modulating cannabis’s anti-inflammatory effects. Inflammation is thought to be a significant factor in many diseases, and CB2 acts as an immune response.
Cannabis contains at least 85 cannabinoids, the chemical compounds that interact with the brain’s receptors. The two cannabinoids people are most familiar with include THC and CBD.
THC, which is responsible for most of psychoactive effects, affects the brain by activating cannabinoid receptors, namely CB1. THC promotes creativity, amplifies your thoughts, and keeps you focused…until stimuli you to a tangential thought (good for philosophical conversations, but for studying, not so much!).
Surprisingly, THC’s (largely) non-psychoactive sibling and the second most studied constituent in cannabis, CBD, shows little affinity to bind to either CB1 or CB2; instead, CBD seems to indirectly stimulate cannabinoid signaling by suppressing the enzyme that breaks down anandamide. This partly explains why CBD appears to counteract some of the effects of THC, and why higher CBD concentrations result in fewer intoxicating effects. Like THC, CBD also plays an important role in appetite, the immune system, and pain management.
The Biphasic Effect: Why Proper THC Dosage is Important
The effects of cannabis vary by individual and are highly dependent on dosing and form of preparation (e.g., vapes, edibles, etc.). It’s important to note that like many chemicals, cannabinoids — THC in particular — have a biphasic effect, meaning low and high doses can have opposite effects in users. This is partly why many people may feel relaxed with low doses of cannabis and paranoid under high doses. Most medical marijuana practitioners advise patients to start with a low dosage and gradually increase dosage as the patient determines how their body reacts. This process is known as “self-titration.”
Another way to think of the biphasic effect is a therapeutic window. Cannabis has a narrow therapeutic range, meaning the difference between the optimal dosage that elicits the effect one desires versus a dosage that creates adverse effects can be subtle. Take chronic pain as an example: most studies of cannabis and chronic pain report that patients find relief in low to moderate doses of cannabis, but may find pain exacerbated when the dosage is too high.
Story Source: The above story is based on materials provided by LEAFLY
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