Does CBD Affect Memory - Updated Research
There's quite a bit of guilt by association with its cousin, THC, which has known negative effects on memory.
What about CBD? Does it run in the family?
We'll need to look at the brain area associated with most strongly with memory and that's the hippocampus.
It also happens to be a manager of mood control!
The effects of CBD (versus THC) are pretty fascinating there.
Here are the areas we'll cover:
- A quick introduction to memory and the hippocampus
- Common enemies of memory
- Does CBD hurt memory
- Does CBD help memory following TBI
- CBD and memory after stroke
- CBD and memory with dementia
- CBD and hippocampus neurogenesis or brain repair
- CBD and serotonin for memory
- What type of CBD for memory
- What's the best CBD to support memory (especially following injury or illness)
To focus on memory, we need to travel a specific part of the brain...the hippocampus.
This small area of our "primitive" brain acts as a seat for both transferring short term to long term memory and the subsequent recall or retrieval of it.
Interestingly, the hippocampus is also a master regulator for mood?
Why would evolution house these two seemingly dissimilar aspects in one place?
Let's dive a bit deeper because this is fascinating.
Mood control is really about emotional memory.
Sadness. Anger. Fear. All powerful players originating from other areas such as the amygdala.
Think of your strongest memories...they usually are marbleized with emotional context.
As researchers put it:
Emotion also facilitates encoding and helps the retrieval of information efficiently.
It's the "bold and italics" for a given memory.
In fact, to a fault as in the case with PTSD or past trauma where the brain is stuck between then and now and physically perceives the memory as currently happening (see CBD and PTSD).
Emotion is a powerful support for memories...like the metal skeleton of a building.
You probably don't remember what you ate 365 days ago...unless it was an anniversary!
The hippocampus having regulation over emotion then makes sense as a means to consolidating memory formation and retrieval.
The hippocampus may be the most dynamic part of the brain in terms of plasticity or ability to change.
That's both a blessing and a curse.
It also makes it the most vulnerable to the various insults of the brain:
- Hyperactive immune response
- Chronic stress
- Trauma and injury
- Drugs, alcohol, and medications
- Excess glutamate
- Impaired repair and growth pathways
Research on the hippocampus and memory actually goes back to the original patient, Henry Gustav Molaison who had his hippocampus removed.
He was then unable to form memories.
We'll see below in the various assaults how this brain is directly impacted.
Indeed, it takes signals from other parts of the brain but the "hub" of memory is indeed here.
As a result of constantly making new memories, the hippocampus is thought to be one of the few brain areas (afer development) that can make new neurons...neurogenesis.
This is critical as we see below to supporting memory and mood control.
Let's turn to some of the usual suspects for memory loss.
Common enemies of memory
There are good reviews on this here but a quick stop since many people may not know what is damaging their memory.
The biggest impacts are due to:
- Lack of sleep...especially deep sleep (see CBD and sleep)
- Medications - a range of drugs impact memory including SSRIs, heartburn meds, antihistamine, bladder control meds, and more basically, they rip acetylcholine which we'll discuss below
- Thyroid - interestingly, this gland has a powerful effect on memory - this is critical for women as they get older due to the autoimmune risk (see CBD and autoimmune) from hormone loss
- Alcohol, cannabis,l and drugs - obvious candidates for memory impairment
- Stress and anxiety - chronic stress is a disaster for hippocampus health - see CBD and hippocampus for anxiety
- Depression - memory loss is likely a result from similar assaults that cause depression - see CBD and depression to learn more
Most of these make sense.
Memories are transitioned are consolidated when we sleep...only in deep sleep.
The medications piece is really fascinating because they're so common and used daily in many cases.
- Statins? Rip acetylcholine.
- Tylenol PM and antihistamines? Rip acetylcholine.
- Antidepressants? Rip acetylcholine.
Acetylcholine is THE target for dementia risk in current research (see CBD and dementia).
So...what is acetylcholine as is applies to memory?
Neurotransmitters and memory
There are two big brain messengers for memory that we'll focus on.
- Serotonin - master regulator of ALL human behavior with side hustles for sleep and memory
- Acetylcholine - our learning and memory neurotransmitter
Other players are involved but many of them are controlled by serotonin (dopamine, norepinephrine, epinephrine).
Glutamate is the "gas" pedal of the brain and it's tied to memory as well.
The issue with glutamate is that we need enough to spur activity but too much is actually destructive. See CBD and glutamate.
GABA is the opposing force there.
Let's turn back to serotonin and acetylcholine though as they're more directly active with memory AND we can affect their levels.
Serotonin and memory
As we mentioned, serotonin governs most of what we would call human behavior. We covered it in detail at our CBD and serotonin pathway review.
The real trick of serotonin for memory however is only recently discovered.
This is one of those situations where we have narrow our research to more recent studies (2015 and later).
Serotonin's secret power is to boost BDNF and other "pro-growth" brain players.
See our artilce on CBD and BDNF
BDNF is the brain's fertilizer and it's key to building new pathways and even new neurons.
Think of what a memory is..it requires a new connection and BDNF is the construction worker there.
More importantly, old memories (physical connections in the brain) require a constant "spraying" of BDNF to maintain existing structures (memories).
The hippocampus can literally atrophy or shrink in size and volume without it since it's so vulnerable to all the various assaults our brain is under.
This applies to both memory formation/retreival AND mood.
SSRI's, the most common type of antidepressants, boost serotonin but if you dig deeper, they lose their effects if BDNF is cut off.
All the research on SSRIs and memory talk about "plasticity". That's the ability of the brain to change and really, it's dancing around one thing...BDNF!
This is critical for addiction as well since addiction at its heart is a type of learning and memory reinforced by dopamine, our reward circuit player.
See CBD addiction to learn more.
In fact, BDNF levels was of the two critical keys to relapse (or lack there of). Stress being the other one (which damages the hippocampus by the way).
Tryptophan, serotonin's precursor also has a role for memory in supporting microtubules...a key physical requirement for memory.
What about acetylcholine?
We did a full review on acetylcholine here.
It's a very fascinating player for memory, learning, focus, and mental health.
In fact, it's the main engine for the "rest and digest" part of the autonomic nervous system.
Look what happens to memory when the parasympathetic nervous system (acetylcholine) is triggered:
These two effects were associated with training-induced improvements in both the trained (attention and processing speed) and transferred (working memory) cognitive domains.
- ADHD IS an acetylcholine issue (hence the effects of nicotine).
- Dementia relies heavily on acetylcholine loss.
- Vitamin D is needed for acetylcholine to function and many of us are deficient.
You can supplement choline are get it from eggs. By the way...the brain AND your steroidal hormones run on cholesterol...the "bad" type LDL It's inflammation you need to address (see CBD and neuroinflammation).
So...what about acetylcholine and memory.
We can go right to the hippocampus and see acetylcholine in action:
First, during spatial memory tasks, cholinergic markers such as ChAT are upregulated [see Park et al. (64)]. Second, ACh levels in the hippocampus are correlated with memory function.
Here's where it gets more interesting:
The classically held view is that ACh is the decider between encoding mode and retrieval mode in memory processing
When rats have their acetylcholine pathways impaired, they do great in a maze until it changes.
They're unable to form new memories essentially.
Newer research is pointing to an entirely different pathway however.
Acetylcholine interacts directly with the immune system to govern aspects of memory.
Immune system? What on earth would that have to do with memory?
In the brain, our immune response generals (called microglia) have a side hustle of managing the "architecture" of our brain.
Cell birth and death is under it's control and think about what memories are!
Connections and neurons which encode memories are "instructed" my microglia and other elements of the immune system.
Interestingly, acetylcholine directly interacts in this process:
In addition to astrocytes, microglia are necessary for hippocampal memory and motor-learning dependent synapse formation, likely via microglial brain-derived neurotrophic factor (BDNF)
Ahhh...there's that BDNF and we come full circle.
Supporting existing memories and making new ones.
Let's get to the question we originally came for.
Does CBD hurt memory
First, does research show that CBD can hurt memory?
Actually, quite the opposite (or we shouldn't spend all this time researching it).
First, CBD is not THC. Thc's effect on memory are well known:
Relatively consistent findings have been reported regarding the acute impairments induced by a single dose of Δ9-THC on verbal and working memory.
Researchers found that many of the mental and mood impairements can be recovered following THC non-use.
What about CBD?
The THC impact is a good place to start as researchers found that CBD countered the negative cognitive effects of THC:
Importantly, participants reported significantly fewer depressive and psychotic-like symptoms at PT relative to BL, and exhibited improvements in attentional switching, verbal learning, and memory.
Do see impacts in the hippocampus?
greater concentrations of CBD have been associated with better cognitive performance, especially memory,14 fewer psychotic symptoms,15,16 and increased gray matter in the hippocampus
More grey matter? People, this is literally more brain mass in the most important area of the brain for memory.
Animal studies have found now impairment on memory from prolonged CBD use:
CBD treatment does not affect spatial learning and long term memory.
There's one caveat from our addiction research.
CBD can help you forget bad memories!
That sounds bizarre but our reviews on CBD and PTSD and CBD and phobias get into this more deeply:
Cannabidiol does so by reducing fear expression acutely and by disrupting fear memory reconsolidation and enhancing fear extinction, both of which can result in a lasting reduction of learned fear.
This figures strongly into anxiety and all mental health since trauma is a common underlying risk.
Addiction is the biggest benefactor of being able to "forget" bad memories such as the "memory" of cocaine cues (see CBD and cocaine addiction).
Research on psilocybin is equally interesting on bad memories..again, BDNF is a big player there.
Let's look at CBD and memory function following various injuries and assaults.
Remember, chronic stress is slow motion trauma in terms of how the brain deals with it.
Does CBD help memory following TBI
We did a full review of CBD and TBI already.
For memory specifically, let's look at FAAH and anandamide.
FAAH is a naturally occurring enzyme that breaks down our brain's key endocannabinoid called anandamide.
In general, anandamide works like a wet blanket in the brain...calming activity with antiinflammatory and neuroprotective effects.
We did a deep dive on whether anandamide's suppression of glutamate (our brain's "gas" pedal) is the reason some people become addicted to cannabis since THC mimics anandamide in the brain.
That review is here.
Here's the interesting piece (and we'll decipher):
Inhibition of the eCB hydrolytic enzymes FAAH (Tchantchou et al., 2014), MAGL (Zhang et al., 2014), and ABHD6 (Tchantchou and Zhang, 2013) have been shown to protect against TBI-induced memory impairments, suggesting that anandamide and 2-AG elevation post-TBI may offer protection from TBI-induced learning and memory deficits.
That's a mouthful...basically if you block FAAH and leave more anandamide in the system, it would protect against memory impairments from TBI.
So..what's the connection with CBD?
CBD also inhibits FAAH, which results in increased anandamide levels.
In fact, this pathway comes across many different issues from schizophrenia (see CBD and schizophrenia) to depression.
Check out the review and also our CBD and brain damage for more insight.
What about stroke?
CBD and memory after stroke
A study looked at induced strokes in mice and found the following:
CBD administration after MCAO led to long-term functional recovery, reducing neuronal loss and astrogliosis, and modulating apoptosis, metabolic derangement, excitotoxicity and neuro-inflammation.
Neuron loss is obvious...especially in the hippocampus.
The other elements deal with immune hyperactive response which is critical to recovery (or lack thereof).
The immune system can actually continue the damage train long after the original stroke with too much brain cell suicide (apoptosis), glutamate (excitotoxicity), and inflammation.
CBD calmed all these responses.
A key issue with stroke is loss of blood flow and oxygen following the injury.
Look at CBD's effect there:
These findings suggest that CBD increases CBF to key regions involved in memory processing, particularly the hippocampus.
We'll do a full review of CBD and stroke shortly but the TBI review is very comparable in terms of the immune systems response and over-reaction.
Let's turn to another surprising result of the immune system in the brain... dementia.
CBD and memory with dementia
We did a giant review of CBD and dementia here with brand new research that's fascinating.
Those little amyloid beta particles? They're actually specific bacteria killers...part of our immune response. Learn more about why they accumulate such high numbers in the review above.
We'll start with the animal studies.
Importantly, CBD also reverses and prevents the development of cognitive deficits in AD rodent models.
How did it do this?
The studies demonstrate the ability of CBD to reduce reactive gliosis and the neuroinflammatory response as well as to promote neurogenesis
Gliosis is activation of immune system and there's our favorite topic...neurogenesis.
Another study found similar results:
CBD treatment was able to reverse cognitive deficits in object recognition memory and social recognition memory without influencing anxiety parameters
Here's the interesting piece with THC:
THC alone had a detrimental effect on cognition in control mice, highlighting the need to be cautious when considering THC as a therapeutic.
But when CBD is added to THC, these results go away!
Again, check out the full review for more information.
Let's turn to our favorite subject finally.
CBD and hippocampus neurogenesis or brain repair
We did a full review of CBD and hippocampus neurogenesis but since that brain area is so integral to memory, let's revisit.
In a nutshell:
Preclinical studies have shown CBD to induce synaptic plasticity and facilitate hippocampal neurogenesis,29,30 with some evidence suggesting that the proneurogenic action of CBD via the hippocampus may underlie its anxiolytic effects
Anxiolytic is technical for anti-anxiety. See how the hippocampus is tied to mood!
Later research goes further into understand this mechanism and it involves boosting anandamide by blocking FAAH.
Interestingly, this result directly offset chronic stress which eats up hippocampus growth.
On a more surface level, the effects on blood flow:
Cannabidiol (CBD) increases cerebral blood flow to areas of the brain associated with memory processing, specifically the hippocampus.
Finally, BDNF...our new best friend.
Cannabidiol Induces Rapid and Sustained Antidepressant-Like Effects Through Increased BDNF Signaling and Synaptogenesis in the Prefrontal Cortex
Goodness...let's translate that because it's too important.
CBD's antidepressant effects were due to boosting BDNF function and resulting "rewiring" (synaptogenesis) of the prefrontal cortex...the section of the brain that makes human, human.
Check out CBD and depression but already, we've seen effects on anxiety and depression, both of which are known causes or at least, associates of memory loss from Harvard's list above.
Exercise and mindful meditation both boost BDNF and neurogenesis so that's three things we can do to support mental health.
Let's turn to serotonin.
CBD and serotonin for memory
We already looked at serotonin's function in memory above.
The serotonin pathway might be CBD's biggest trick.
Technically, CBD is an allosteric negative modulator of serotonin function.
This basically means it's a feedback mechanism!
CBD won't continue to boost serotonin in one direction which is critical because too much serotonin is just as bad (maybe worse) as too little.
It's called serotonin syndrome - see CBD and serotonin syndrome or CBD and serotonin.
What does research show CBD?
A study looked at how injury exhausts our serotonin function (can be physical or even emotional stress) and CBD's effect:
Overall, repeated treatment with low-dose CBD induces analgesia predominantly through TRPV1 activation, reduces anxiety through 5-HT1A receptor activation, and rescues impaired 5-HT neurotransmission under neuropathic pain conditions.
Reduction of pain. Reduction of anxiety via serotonin.
"Rescue" of 5-HT (serotonin) transmission. Goodness...rescue is the most important word in that statement.
Remember...serotonin boosts BDNF!
One note on serotonin...it's a primary stress response buffer.
Look at the effects of stress on memory:
A pronounced working memory deficit was associated with exposure to stress.
Chronic stress is the enemy of hippocampus function which makes serotonin and anandamide (both stress response buffers) so important.
CBD has been shown to "rescue" and support both in research.
Let's look at more practical questions.
How much CBD to support memory
We have good research on neurogenesis, a key to repair following injury.
Studies show that this effect peaks at 300 mg and then goes down from there.
Based on that 300 mg would the peak level long term for recovery/repair as it applies to memory since the hippocampus is directly affected by this effect.
Lower levels may help general cognitive and memory support.
Everyone is different in terms of liver processing, endocannabinoid system. Etc so test to see how you feel.
Also, look at the following:
NAC - key support of antiinflammatory - anti-oxidant system
Magnesium - supports Vitamin D and calms activity by blocking glutamate
Berberine - supports gut health and gut barrier to calm systemic inflammation
Vitamin D - critical steroid that many people are deficient in
What type of CBD for memory support is a common question.
What's the best CBD to support memory (especially following injury or illness)
First, the basic requirements:
Organically grown in the US at FDA registered farms
3rd Party Tested
No THC - THC pushes in one direction be it immune suppression or otherwise.
No Heavy metals
We test ours twice since the whole family uses it.
Then there's the question of full spectrum versus CBD isolate.
All the research above and the dozens of NIH studies referenced across the site are based on CBD isolate.
We go into full spectrum versus CBD isolate here but the bigger issue is histamine response.
40-60% of the population has histamine issues (goes up for women and as we get older).
Histamine response is a part of our immune system and the last thing we want to do it trigger that system further.
Then there's the question of cost.
We noted that peak neurogenesis is at 300 mg.
The key then is cost per mg of CBD.
That's why we price our 6000mg bottles at about 2-3 cents per mg of CBD before discounts up to 30%.
The reason is simple...we've been there.
If you read the founder's story here, it is one of trauma and recovery from a brutal perimenopause.
For women, estrogen supports serotonin which boosts BDNF. Progesterone supports GABA and calms immune response.
We've been there and want to make CBD available to as many people as possible.
Be well. Take care of each other. Take care of yourself.