Almost everything the brain does is a balancing act.
Neurons pass signals to each other in two directions. Excitatory signals speed things up by telling downstream neurons to fire more, to activate, and respond. Inhibitory signals slow things down by telling downstream neurons to quiet, to hold back, and wait. A brain that is functioning well is not a brain running at full speed. It is a brain constantly modulating between activation and restraint, tuned to the situation.
The primary molecule the brain uses for restraint is called gamma-aminobutyric acid (GABA). GABA is the brake. When you take a Xanax to calm down, you are aiding the natural process of GABA. When you take an Ambien to fall asleep, you are boosting the activity of GABA. Anti-seizure medications may work, in large part, through GABAergic mechanisms. When the brake fails or gets sluggish, the consequences can be severe: anxiety, insomnia, muscle rigidity, and, in the most dramatic cases, seizures.
The endocannabinoid system, it turns out, is deeply involved in how the brake works. Not in the way you might expect. And understanding that relationship gets us close to why the plant compound cannabidiol (CBD) has changed the medical conversation around cannabis in ways that would have seemed impossible fifteen years ago.
This is the fifth piece in a series on how the endocannabinoid system relates to the other chemical messengers in your body. We’ve covered endorphins, oxytocin, dopamine, and serotonin. GABA is the most consequential comparison in the series so far, because it is where the science becomes clinical.
What GABA Actually Is
GABA is a small molecule (an amino acid derivative) produced throughout the brain and spinal cord. It is the primary inhibitory neurotransmitter in the mammalian central nervous system. Roughly a third of all synapses in the brain use GABA to slow things down.
GABA operates through two main receptor families. GABA-A receptors are fast-acting, ion-channel receptors that open in milliseconds when GABA binds. They are the target of benzodiazepines (Xanax, Valium, Ativan), barbiturates, Z-drugs like zolpidem (Ambien), general anesthetics, and a significant portion of anti-seizure medications. GABA-B receptors are slower and act through G-protein signaling, and they play roles in muscle relaxation, spasticity, and certain aspects of mood and cognition.
When someone experiences an anxiety disorder, chronic insomnia, or certain forms of epilepsy, the underlying story is often, in part, a story about GABA. The brake isn’t working the way it should. The nervous system runs hot. Circuits that ought to quiet down don’t. Signals that ought to be dampened aren’t. The consequences show up in different ways in different conditions, but the mechanism has a common thread.
This is where the endocannabinoid system enters in ways that turn out to be more nuanced than a simple “one system helps the other.”
What Endocannabinoids Actually Are
For readers new to the series: endocannabinoids are lipid-based molecules produced by your body throughout the central and peripheral nervous systems. The two most studied are anandamide (AEA) and 2-arachidonoylglycerol (2-AG). They bind to CB1 and CB2 receptors, which are distributed widely throughout the brain, immune system, and other tissues. Together with the enzymes that build and break down these molecules, they form the endocannabinoid system, one of the body’s primary regulatory networks, involved in mood, pain, appetite, sleep, immune function, memory, and reward.
If you’d like a more detailed foundation, our back-to-basics guide on endocannabinoids covers the fundamentals.
The cannabis plant produces phytocannabinoids to include THC, CBD, and a growing number of minor cannabinoids that interact with this system. What follows is the story of how they meet GABA.
The Endocannabinoid System Regulates the Brake
Here is one of the most well-established findings in modern neuroscience, and one of the most striking mechanisms in the endocannabinoid system.
When a neuron receives a signal strong enough to depolarize it something happens on the receiving end. Endocannabinoids are manufactured on demand from the cell membrane, released into the synapse, and travel backward across the connection. They bind CB1 receptors on the sending neuron, and they tell it to stop releasing GABA.
This is called retrograde signaling. And when the neurotransmitter being suppressed is GABA, which is the case in many brain regions, particularly the hippocampus and amygdala. The phenomenon has a specific name: depolarization-induced suppression of inhibition, or DSI. In plain language: the receiving neuron releases the brake on the sending neuron, giving itself a temporary window of increased activity.
This mechanism is a fundamental part of how the brain fine-tunes its circuits. It allows individual neurons to briefly quiet the input that would otherwise slow them down, which is important for learning, memory formation, emotional processing, and the countless other functions that require precise control over the balance of excitation and inhibition. Research published in journals including Journal of Neurophysiology, Journal of Neuroscience, and Science have established this mechanism as one of the endocannabinoid system’s core functions in the brain.
But it also means the endocannabinoid system has a delicate job. Endocannabinoids suppress GABA release, acting as the “brake”/ If endocannabinoid signaling runs too strong, or in the wrong places, the brake fails to engage when it should. This is part of why cannabis, which activates CB1 receptors through THC molecules, can produce short-term memory effects, and why it can, in some users, produce anxiety rather than reduce it. THC engages the same suppress-the-brake mechanism the body uses naturally, sometimes in regions where more inhibition, not less, would have been helpful.
CBD Does Something Almost Opposite
Now here is the part of the story that makes CBD such an unusual compound.
CBD does not bind CB1 receptors strongly. It does not engage the retrograde suppress-the-brake mechanism the way THC does. Instead, CBD acts through what pharmacologists call positive allosteric modulation of the GABA-A receptor. In plain language: CBD does not directly activate the receptor, but it makes the receptor more responsive when GABA arrives. It boosts the brake rather than releasing it.
This is a mechanism reminiscent of how benzodiazepines work but at a different binding site, and with a substantially different clinical profile. A 2017 study in Pharmacological Research was the first to demonstrate this action directly, showing that CBD is a positive allosteric modulator at the GABA-A receptor. Subsequent research, including a 2024 study using both rat and human epileptic brain tissue, has confirmed and extended the finding: CBD enhances inhibitory currents at GABA-A receptors, particularly in tissue where inhibition has been compromised. The effect appears to develop specifically in states of nervous system dysfunction, which is part of why CBD has therapeutic action in seizure conditions without producing sedation or dependency the way benzodiazepines can.
So the endocannabinoid system, working with its own molecules, suppresses GABA release in specific circuits. And CBD, working from outside the body, enhances GABA-A receptor sensitivity to strengthen inhibition. These are not the same mechanism. In some contexts, they may act in opposite directions. This is one of the reasons a whole-plant cannabis product, or a full-spectrum extract, is not simply “more of one effect.” Different compounds in the plant engage different parts of the same broader system, and the net result depends on which compounds are present, in what ratios, and in what physiological context.
Minor Cannabinoids and GABA
The larger cannabis plant has more than a hundred compounds, and research on the minor cannabinoids (the ones that show up in smaller quantities than CBD and THC) has expanded significantly in recent years. A number of these compounds also appear to engage the GABA-A receptor.
Cannabichromene (CBC) has been shown in recent research to positively modulate GABA-A receptors and to demonstrate anti-seizure activity in animal models of Dravet syndrome. Cannabinol (CBN) often marketed as “the sleepy cannabinoid” has more mixed evidence. A 2021 systematic review in Cannabis and Cannabinoid Research concluded that the sleep claims for isolated CBN outpace the available clinical data, though newer animal research from the University of Sydney (published in Neuropsychopharmacology in 2024) has found more compelling evidence that CBN influences sleep architecture, including a possible connection to GABAergic activity. A 2024 human trial found CBN modestly improved sleep quality relative to placebo.
The takeaway isn’t that any single minor cannabinoid is a proven treatment for any specific condition. It is that the cannabis plant contains multiple compounds that engage the GABA system in different ways, which is one of the reasons full-spectrum cannabis products often produce effects that isolated compounds don’t fully replicate.
Where the Two Systems Differ
To pull the comparison fully into view:
Chemistry: GABA is a small amino acid derivative. Endocannabinoids are lipids. The two are chemically unrelated, and they are produced through entirely different biosynthetic pathways.
Direction of signaling: GABA is a forward-signaling neurotransmitter released by a sending neuron, it acts on the receiving neuron. Endocannabinoids are largely backward-signaling released by the receiving neuron, they act on the sending neuron. This retrograde direction is part of what makes the endocannabinoid system a regulator rather than a driver.
Storage: GABA is stored in vesicles, ready for release when a neuron fires. Endocannabinoids are not stored at all, they are synthesized on demand, used, and then broken down.
Scope: GABA is heavily focused on one job: inhibition. It shapes the brain’s balance between activation and restraint, and it is the target of many of the most-used medications in psychiatry and neurology. The endocannabinoid system is a generalist, involved in dozens of physiological processes, of which the regulation of GABA is only one.
Plant interactions: GABA-A receptors are the target of benzodiazepines, barbiturates, and Z-drugs, which are powerful pharmaceuticals with most carrying significant risk profiles. The cannabis plant produces compounds that engage GABA-A receptors through a different binding site, with, so far, a very different safety profile. This is not the same as saying CBD is a benzodiazepine or that any cannabinoid is a substitute for prescribed medication. It is to say that plant compounds engaging the same receptor family through a different mechanism can produce different clinical outcomes, and that this is a real area of research.
Why This Matters
If there is one comparison in this series that most clearly demonstrates why the endocannabinoid system is worth understanding, not as a cannabis-related curiosity, but as a fundamental part of human physiology, it is this one.
Your brain has a brake and it is one of the most important systems in your nervous system, and its function affects everything from whether you can fall asleep tonight to whether you experience anxiety in ordinary situations to, in the most severe cases, whether the electrical signals in your brain stay coordinated at all. The endocannabinoid system is deeply involved in regulating that brake. And cannabis-derived compounds (CBD in particular) interact with the brake in ways that have real clinical relevance for conditions that have historically been very difficult to treat.
If you are exploring cannabinoid therapies for anxiety, sleep, seizures, or another condition, our care team is available worldwide at no cost. If you are a candidate for participation in observational research, our Observational Research Registry — the largest of its kind in the United States, and an ongoing partnership with Johns Hopkins University — welcomes patients from anywhere in the world. And our Research Library holds peer-reviewed studies on cannabinoids and human health.
Coming Up Next
Future pieces in this series will examine how endocannabinoids interact with cortisol and the body’s stress response, with norepinephrine and the alertness system, and with other major chemical messengers. Each comparison shows a different facet of the same underlying network of your body’s internal regulatory chemistry, of which the endocannabinoid system is one of the most far-reaching and least talked-about parts.
