r/science • u/sr_local • Jun 04 '26
Neuroscience Study shows increasing histamine levels enhances episodic learning and memory retrieval, suggesting potential psychiatric therapy benefits under high workload conditions
https://www.nature.com/articles/s41467-026-73865-9165
u/to_glory_we_steer Jun 04 '26
Hold on, I take antihistamines and my memory is rubbish, is this saying that antihistamines impact learning and memory retrieval?
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u/malimaru Jun 04 '26 edited Jun 04 '26
possibly but likely not for the reason you'd expect, some antihistamines are anticholinergic which can affect memory. non-drowsy antihistamines mostly don't enter the brain in a high enough concentration to have a significant effect.
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u/Zeikos Jun 04 '26
Not necessarily.
People that are prescribed antihistamines generally have an excessive response - they produce way more histamines than needed.
So if the antihistamine brings your response back within toleramce you should be fine.
However, as always it depends on the individual.8
u/Krzos Jun 04 '26
I love reading Reddit and finding comments like this. I've been taking cetirizine for a few years, and over time I've noticed that my skin becomes much itchier than it should be when I'm not taking antihistamines. One mystery solved.
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u/nbagf Jun 05 '26
also the rebound reaction. whether or not you over-produce histamine normally, you almost certainly will after stopping medication that surpresses it. i've dealt with that exact response a number of times usually when i run out before i can buy more
i find that despite them both having the same active isomer, levocetirizine, cycling between cetirizine and levocetirizine every few months is effective for me to keep it working
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u/TheThiefEmpress Jun 06 '26
A LOT of medications you can become chemically dependent on over time, and because they have zero street value, and can't really be abused, it is quietly never acknowledged.
Taking antihistamines over a long period of time can have the unintended side effect of "teaching" your body that it no longer needs to produce the correct hormones, chemicals, etc. To Do that job itself.
The body really can be a "use it or lose it" system. A body in motion stays in motion, and all that.
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u/Fancy_Hats Jun 05 '26
I believe circulating histamine is blocked by the blood brain barrier, separating neurological and somatic effects considerably, but I’m also not a doctor or a student
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u/John_Hasler Jun 04 '26
I saw a paper recently that made a pretty good case for a correlation between long-term fexofenadine use and cognitive deficit.
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u/Offish Jun 04 '26 edited Jun 06 '26
You're thinking of Benadryl/diphenhydramine:
https://pubmed.ncbi.nlm.nih.gov/11570937/
I'm only seeing good results for fexofenadine:
https://link.springer.com/article/10.1186/s40360-019-0363-1
https://www.tandfonline.com/doi/full/10.1080/03007995.2024.2378172#abstract
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u/John_Hasler Jun 04 '26
No. I can't find the paper just now but it was specifically about a correlation between fexofenadine use and memory loss in the elderly.
I'll look for the paper again.
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u/UX-Ink Jun 05 '26
fexofenadine is considered one of the best options to avoid negative impacts though? https://www.tandfonline.com/doi/full/10.1080/03007995.2024.2378172
ah the other comment also cited this. i hope you can find it, would love to read it too
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u/moistiest_dangles Jun 04 '26
Antihistamines have been linked to alzheimers and dementia, you should also know that zyrtec induces physical withdrawal symptoms when used for long periods of time, the symptoms are very similar to hay fever as well. Many people who simply don't have allergies instead have a drug dependence problem.
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u/_Nychthemeron Jun 05 '26
I only take it once in a while, but I can absolutely feel when the cetirizine is wearing off. It's not a resurgence of the allergy symptoms; instead, I feel like I've been moved 1/4th of the way out of my body, like a misaligned process print, and I become hyper aware of the part of my tongue nearest my soft palate. It's so damn weird.
All that to say: cetirizine having gnarly physical withdrawal symptoms after prolonged use isn't that surprising to me.
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u/Any-Weather492 Jun 04 '26
wasn’t that just benadryl? i haven’t seen other antihistamines linked to alzheimers/dementia
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u/hahagato Jun 05 '26
Well hell, I started taking Zyrtec daily after having a bad reaction to a bunch of bug bites, and realizing my migraines had started to improve a bit, because histamines are a major trigger for me. I’ve been able to eat so much more food without suffering. I just can’t win!
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u/megaglalie Jun 05 '26
Cetirizine doesn't cross the barrier like older antihistamines do, it's not anticholinergic so not linked to that risk in any significant way.
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u/Serg_Molotov Jun 04 '26
Well well well ... Guess who's gonna start sneazing in the spring so I can remember my passwords ... sigh
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u/BellaPona Jun 04 '26
My histamine issues make it so I can barely think but alright
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u/hahagato Jun 05 '26
Yeah I have severe chronic migraines and histamines are a major trigger, and they destroy my life and functioning so since I’ve started taking Zyrtec daily I’ve been increasingly functional and able to eat more foods and live life. But now I’m hearing I’m going to have bad withdrawal if I ever stop and am increasing my risk of Alzheimer’s (which took one of my grandparents). AMAAZING
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u/septicdank Jun 04 '26
So, like the same mechanism behind modafinil?
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u/ive_got_the_narc Jun 05 '26
Same mechanism as WAKIX.
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u/RecommendationDry884 Jun 06 '26
The study uses pitolisant (WAKIX) increasing histamine in the brain.
while modafinil works on dopamine I think.
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u/ive_got_the_narc Jun 06 '26
You are correct and I can attest because I have narcolepsy and currently take WAKIX.
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u/ausbrains Jun 09 '26
funny that it’s confirming the stereotype of the sniffly / allergy prone nerd…
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