Cannabinoids & The Brain

Cannabinoids and the Brain

Cannabinoids are the psychoactive chemicals which create the euphoric properties we experience when we inhale or consume the resinous substances found in the female cannabis flower. Through the years, research has allowed us to further understand how these chemical substances affect us biologically and what benefits are possible with this highly complex substance.

In this article, I review the most well-known chemicals that are classified as cannabinoids and the processes related to them that we understand.

How Cannabinoids Affect Us:

Cannabinoids are the heart of the psychoactive properties of cannabis. There are over 480 natural chemicals unique to the marijuana plant. Of them, only 66 have been classified as cannabinoids. How these interact with our biology however is interesting. There are two neurotransmitter receptors in the body that are impacted by cannabinoids. These are called CB1 and CB2. These receptors are naturally found in different parts of our bodies in different concentrations. CB2 receptors are more abundant in the peripheral and extremities of the body. Whereas CB1 receptors are concentrated in the central nervious system, including the brain. Together they are commonly referred to as the “endocannabinoid system”.

The actual effects that the cannabinoids have reflect the areas of the brain they interact with. There are three major regions where interactions tend to occur. Cannabinoids interact with our limbic system, which is the part of the brain that affects memory, cognition and psychomotor performance. They also activate the mesolimbic pathway, which is associated with feelings of reward. Finally, and importantly, cannabinoid receptors are also widely distributed in regions of the brain that control the perception of pain.

It has been well understood that THC plays the largest role in producing the intoxicating effect on the nervous system, however it is not as simple as was once thought. A lot of knowledge about the way that THC works was gained from work with a synthetic version of THC. It was developed for research into its potential to treat nausea and relieve discomfort for those on chemotherapy. However, it quickly became clear that this synthetic version did not compare to its natural counterpart. Something was off.

It had previously been suggested that the THC in cannabis was not the only chemical that was responsible for the psychoactive characteristics. The work with synthetic THC in isolation, provided further evidence that the psychoactive effects of cannabis are not the result of any one chemical. We now know that the effects that cannabis has on the brain emerge because of interactions among many of the chemicals we call “cannabinoids”.

The Cannabinoids:

CBGA (Cannabidiolic Acid)

CBGA is the major precursor to most of the well-known cannabinoids. It is responsible for most of the major psychoactive compounds that we care about. Without CBGA, cannabis would not be anything special. CBGA goes through several chemical processes which turn the substance into THCA and CBDA.

THC (Tetrahydrocannabinol)

THC is probably the most well-known chemical to cannabis users. This substance has the largest individual psychoactive effect on the body. THC interacts with both our CB1 and CB2 receptors. As a result its effects are felt throughout the body and the brain. The CB1 receptor affects memory, mood, sleep, and pain. It is the interaction between THC and our CB1 receptor that allows humans to experience the intoxicating "high" associated with using marijauna. The effect that THC has on our endocannabinoid system is the primary driver for the changes in memory, cognition and psycho motor performance. However, as discussed above, the effects of THC are believed to be moderated by the influence of the other cannabinoids, most particularly CBD.

CBD (Cannabidiol)

CBD is a very important chemical that is strain dependent and has been largely bred out of many strains. However, it is no longer in danger of disappearing as breeders are now cultivating high CBD strains for medicinal use.

Despite what you may believe, in isolation, CBD is non-intoxicating. However, it does appear to have psychoactive characteristics such as the ability to calm anxiety and ease depression. There is also evidence that CBD influences the psychoactive and intoxicating effects of other cannabinoids, especially THC.

CBD may be non-intoxicating, but it plays significant roles in how cannabis affects our bodies. CBD has a greater affinity for the CB2 receptor than for the CB1 receptor. The CB2 receptors are found in the immune system and are associated with the control of inflammation in the body. As a result, the effects of CBD are felt mostly in the body. Because of its affinity with the CB2 receptor, CBD is generally considered to have more medicinal properties than THC. It appears to relieve convulsion, inflammation (and thereby also migraines), anxiety and nausea. That is why strains with a high concentration of CBD are more desirable for medicinal use.

Trials have been done with synthetic THC and CBD in combination. They found that anxiety, discomfort, and schizophrenia were significantly reduced when THC was administered alongside CBD. Even though CBD is not intoxicating, it obviously influences the characteristics of how THC interacts with the CB receptors in our nervous system. This interaction is known as the modulation of the endocannabinoid system. This is not limited to just CBD, in fact it is likely that many more cannabinoids play a part in the overall psychoactive and intoxicating properties of cannabis. This truly shows its complexity.

CBN (Cannabinol)

The third most important cannabinoid is CBN. It is a mildly psychoactive compound; however, its most pronounced effect is as a sedative. It is well recognized and advertised as a sleep aid for those that struggle with insomnia. However, the sedative effects of CBN are probably less comforting than the similar effects produced by CBD.

Both THC and CBD are by-products of Cannabidiolic Acid. CBN is a substance that is produced by the further degradation of THC. As THC is exposed to oxygen it oxidizes and the resulting chemical is CBN. While CBN produces sedative effects, the effects produced by CBD are more desirable because CBD has a greater affinity for the CB2 receptors in our bodies. The CB2 receptors are associated with effects felt more throughout the body rather than in primarily in the head.

Many growers falsely believe that the sedative effects of late harvested cannabis are caused by increased levels of CBD. In reality, the amount of CBD is determined by the genetics of the strain. However, the sedative effects are real! They are caused not by an increase in the desirable CBD, but rather by the degradation of THC into CBN. When you allow your trichomes to turn amber and harvest late, you are allowing THC to degrade into the less desirable CBN.

CBC (Cannabichromenes)

CBC is not psychoactive, it does, however, produce many beneficial effects. It is an antidepressant, anti-inflammatory, anti-fungal and antibacterial. It also has a potential effect on pain management.


Terpenes are a newfound product of interest. They are the fragrant oils that give cannabis its unique and pungent smell. Terpenes are responsible for the different smells and flavors that different strains of cannabis have. The terpenes found in many strains are distinctive and often evoke familiar tastes and aromas. Terpenes are responsible for strain names such as blueberry, sour diesel, and many others. These oils are secreted in the flowers’ resin glands, the same place where cannabinoids are synthesized.

It is thought that terpenes play a role very similar to other modulating cannabinoids, such as CBD. Where the interaction of terpenes with CB receptors, modulates the overall psychoactive characteristics of the strain. The exact science of these terpenoids however is not conclusive, more research is needed on the aspects of how or even if these terpenoids impact the interaction of the endocannabinoid system.


There are many other chemicals in cannabis, both psychoactive and not, but they are less understood and have less individual impact. However, cannabinoids work in cooperation and the specific combination of cannabinoids likely have a substantial effect that alters the overall experience and effect.

How we can manipulate these chemicals to better suit our agenda really comes down to strain, genetics, cultivation, breeding and what we ultimately prefer. There's still so much we don't know but we do have a strong grasp on the basic fundamentals of this magical drug.

Author: Dr Photon

"Being wrong is an opportunity for getting things right."

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You are responsible for knowing and following the local laws that pertain to cannabis cultivation, possession, and use. Decisions to grow cannabis should be made in consultation with a lawyer or qualified legal advisor. Decisions to use cannabis should be made in consultation with your doctor or medical professional.