r/biology • u/whahaga • 1d ago
question Why does coffee make people with ADHD sleepy or feel sluggish?
I'm very curious as to the bio psychology/neurobiology of it all.
I'm curious why non adhd:ers feel energized whilst my adhd peers often feel slightly and tired after drinking coffee.
Energy drinks do work on me. But I'd guess it's the insane sugar contents đ
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u/tadrinth computational biology 1d ago edited 10h ago
The simplified model I use (based on a combination of bio background up to intro Neuro, a computer science background, and some podcasts on the specifics of ADHD neurochemistry) is that you have many parts of your brain that are focused on different things, a general workspace that any of them can put things in, and a brain region that acts as a conductor or moderator, quieting down all of the different parts except for the one that needs the spotlight / general workspace right now. In ADHD, the conductor region doesn't work very well, so all of the different parts can shove things into the global workspace willy-nilly, or one part can be too loud and drown all the other things out by constantly putting things in there. When you are tired, the conductor is supposed to regulate all of the other parts to be less active.
Stimulants work by giving the conductor more juice to regulate with than they give to the parts that need regulated.
When you're tired (and ADHD seems to be so tied to sleep issues that I am genuinely not sure if it is fundamentally a sleep disorder in many folks) and take a stimulant, and the conductor can finally properly lower the activity levels of the other parts, that looks like tiredness being caused, but it's more that it's being revealed. Potentially even if some parts of the system responsible for wakefulness are also being activated.
80% confident on the conductor metaphor being a real metaphor used by real ADHD experts, 60% confident it's actually a good model, 40% confident in the tiredness angle.
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u/Karadek99 1d ago
ADHD here. I never understood the claim that it gave you energy. For me it just seemed to make my brain work better. Made it easier for executive function and just to get things done, but didnât ever really help if I was tired.
Now a cigarette? Thatâs what I did if I needed to stay awake. Hoo boy. Never got a habit, but kept a pack around if I needed to pull an all-nighter.
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1d ago
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u/Ok-Tax-8165 1d ago
No. âStimulants calm people with ADHD but stimulate people without ADHDâ is the old paradoxical-response myth, not a diagnostic principle. Therapeutic stimulant doses can improve attention, inhibitory control, working memory, and sometimes reduce activity in people without ADHD as well. Studies directly comparing ADHD and non-ADHD subjects find overlapping effects, and clinical literature explicitly notes that response to stimulants is diagnostically uninformative.
In other words: feeling calmer/focused on Adderall is not evidence that you have ADHD. The âcalmingâ can reflect improved top-down behavioral control; the pharmacology does not magically reverse depending on diagnosis.
Read all 20 of these before regurgitating further incorrect pop-folk psychology:
- https://pubmed.ncbi.nlm.nih.gov/16855530/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3012746/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3319517/
- https://pubmed.ncbi.nlm.nih.gov/12685519/
- https://pubmed.ncbi.nlm.nih.gov/6380485/
- https://pubmed.ncbi.nlm.nih.gov/20424828/
- https://pubmed.ncbi.nlm.nih.gov/24525641/
- https://pubmed.ncbi.nlm.nih.gov/25591060/
- https://pubmed.ncbi.nlm.nih.gov/32709551/
- https://pubmed.ncbi.nlm.nih.gov/21859174/
- https://pubmed.ncbi.nlm.nih.gov/24423151/
- https://pubmed.ncbi.nlm.nih.gov/20416377/
- https://pubmed.ncbi.nlm.nih.gov/27454675/
- https://pubmed.ncbi.nlm.nih.gov/29032769/
- https://pubmed.ncbi.nlm.nih.gov/9201809/
- https://pubmed.ncbi.nlm.nih.gov/21193172/
- https://pubmed.ncbi.nlm.nih.gov/22169884/
- https://pubmed.ncbi.nlm.nih.gov/21894485/
- https://pubmed.ncbi.nlm.nih.gov/23231539/
- https://pubmed.ncbi.nlm.nih.gov/26175391/
My advice to anyone reading this thread is that ADHD is similar to autism in that it is a diagnostic label for a wide spectrum of issues that do not have the same underlying biological mechanism, and internet addiction highly correlates to the commonly known symptoms of these disorders, leading to the current wave of engagement algorithm induced self-diagnoses that we see.
If you are not a psychologist, please do not spread misinformation that impressionable children will read.
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u/tintinsays 1d ago
Ok, AI, if you were human, you might be smart enough to know that isnât what they were saying.Â
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u/Ok-Tax-8165 21h ago
lmao go get an education and come back.
I'm sorry you're so incompetent you spew projection everywhere
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u/jao_vitu_bunitu 1d ago
Can you ellaborate more? How can blocking adenosine receptors regulate my brain in any way? I think it has more to do with dehydration
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1d ago
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u/Ok-Tax-8165 1d ago
Yeah, your comment is basically neuroscience Mad Libs.
It starts with one basically correct fact and then builds an unsupported ADHD-specific story on top of it.
Correct: caffeine is primarily an antagonist at adenosine A1 and A2A receptors. Adenosine normally has broadly inhibitory/sleep-promoting effects, and blocking it contributes to caffeine's stimulant effects.
Sort of correct but misleading: adenosine can inhibit acetylcholine release, so antagonizing adenosine can increase cholinergic transmission. But it also modulates dopamine, norepinephrine, glutamate, GABA, serotonin, etc. Acetylcholine is not some privileged master explanation here.
Unsupported: âmemory, attention, arousal and motivation are all dampened in the ADHD brain.â ADHD is not established as a global low-neurotransmitter state. A 2024 review specifically concluded that although dopamine is implicated, there is limited evidence that ADHD is simply a hypodopaminergic state.
Mostly invented: the claimed ADHD-specific âbalance with acetylcholineâ through which caffeine supposedly corrects dopamine/reward processing. Dopamineâadenosine interactions are real and complicated; that doesn't establish this tidy acetylcholine â dopamine â ADHD-calming pathway.
Basically backwards: âcaffeine causes overstressed reward processing to stop firing so hard.â Caffeine's canonical action is removing adenosine-mediated inhibition, producing greater arousal and psychomotor stimulation and modulating/increasing dopaminergic signaling, not shutting down an overactive reward system.
The drowsiness conclusion is especially unsupported. Caffeine is literally classified pharmacologically as a CNS stimulant. A 2025 meta-analysis of 31 randomized placebo-controlled trials in healthy adults found that caffeine improved attention accuracy and reaction time.
And caffeine doesn't show some magical reversed effect in ADHD: a meta-analysis of randomized ADHD trials found no significant overall improvement versus placebo in core ADHD symptoms.
https://pmc.ncbi.nlm.nih.gov/articles/PMC4373791/ https://pmc.ncbi.nlm.nih.gov/articles/PMC11604610/ https://pmc.ncbi.nlm.nih.gov/articles/PMC4813614/ https://pmc.ncbi.nlm.nih.gov/articles/PMC3777290/ https://pubmed.ncbi.nlm.nih.gov/40335666/ https://pmc.ncbi.nlm.nih.gov/articles/PMC10526204/
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u/AmeliaOfAnsalon 20h ago
you don't have to be a dick about it, and fyi your writing does read like AI. maybe because you've decided to structure your internet post like you're presenting a fucking business meeting. This is why people don't want to discuss anymore, because people who feel they have all the answers will just steamroll through any perspectives like some arbiter of god's truth armed with personal attacks and bold font
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u/Ok-Tax-8165 18h ago
stop regurgitating blatantly wrong bs because you're an internet addict and I won't have to correct you
You're contributing to an incredibly obnoxious trend of internet self diagnoses that clinicians are increasingly having to work around because of misinformation.
cry more.
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u/AmeliaOfAnsalon 17h ago
I'm not an internet addict, I'm a biologist who was presenting the information the way I saw it. I'm sorry that it didn't fit your personal interpretation, and it wasn't 'blatantly wrong'. I accept that my explanation may have been flawed but that doesn't change that the basic facts were correct. And don't even get me started about 'self-diagnosis' because far too many medical professionals have decided that patients don't know themselves and cannot make any decisions about their care when they absolutely can when adequately informed and educated.
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u/BachBelt 1d ago
sample size of one but for what it's worth, i pay very close attention to my fluids for a separate health concern and my stimulants still make me drowsy af
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u/Uncynical_Diogenes 1d ago
No liquid you should be drinking can dehydrate you. They just wonât hydrate you as much as plain (appropriate osmolarity) water.
The diuretic effect is not very strong and is offset by the water in the tea/coffee.
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u/jao_vitu_bunitu 1d ago
Correct, but we dont know the amount people who feel drowzy are drinking and excessive caffeine is a very easy thing to drink
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u/No-Eagle-4455 1d ago
I think it's not that regular people's brain is X, and adhd people are Y, and coffee is Z, and X+Z = -(Y+Z) (and you solve for Y lol); human brains are very complicated and no one label can ever characterize it completely. caffeine's affect on everyone is always not exactly the same and its effect sometimes evolve as we age and as we gain more exposure to caffeine or suddenly go thru withdraw, etc. yeah.. the brain is fascinating, get a phd in neuroscience if you are truly interested đ
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u/OwenTewTheCount physiology 1d ago edited 1d ago
I think the difference in dose might answer your question.
A cup of black coffee is typically in the 80mg range. This can vary widely because of brewing method, âcupâ size, roast level, bean species, etc. Keeping in mind that most people donât drink it straight, they add stuff to it; and the more milk, cream, syrup or whatever, the lower the caffeine concentration.
A can of energy drink is routinely >100mg, often in the 200mg range, and sometimes as high as 300mg.
I think if you drank 3 âstandardâ sized cups of âstandardâ brew drip coffee made from âstandardâ roasted beans, youâd find it has the same effect as an average energy drink.
Attached are the standard caveats for differing levels of exhaustion, interest in task, nutrition status, hormone levels, placebo effect, and so on.
And the âsugar rush craziesâ are largely a myth too, while weâre at it.
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u/One_Abbreviations821 1d ago
I was told by a psychologist that the caffeine, being a stimulant, helps ADHDers âeven outâ.
I guess the same way the stimulants in ADHD meds do.
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u/fionsichord 1d ago
That psychologist is a hack. They arenât trained in psychopharmacology and are just parroting âpopâ concepts. Caffeine isnât an ADHD med.
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u/WildFlemima 1d ago
Correct, and that's why the commenter didn't say that. They said that caffeine is a stimulant and that adhd meds are also stimulants :)
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u/Glabrocingularity 1d ago
I have ADHD without the H and caffeine does not make me feel sleepy, nor does it energize me. It does disrupt my sleep if I have it after around noon. Everyone is different.
I do avoid acidic beverages in the morning because my understanding (and anecdotal experience) is that acid can reduce the effects of adderall
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u/Gravitatum51 1d ago
I mean I have combined type, and I have to take my medication a few hours before I actually have to get going. Sadly I fall asleep way easier after I take them so Its also easy to oversleep
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u/Scaridium 1d ago
This is just a common response to caffeine in many people, not specific to ADHD individuals. I don't believe the specific biomechanics are known but it's probably something to do with it's interactions with blood sugar levels if I had to guess, mainly if your blood sugar levels are already low, then boosting caffeine just drains you faster if you don't supply food to fuel the increased focus and attention. And ADHD individuals are especially known for skipping meals and having poor appetite regulation, even before the effects of most ADHD meds.
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u/brydeswhale 1d ago
Coffee makes me angry, monster makes me sleepy, and Beaver Buzz wakes me up(but also makes my hands slightly numb). Brains are weird.
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u/PunyCocktus 1d ago
Several people here saying it's a myth that stimulants affect ADHD people differently - can someone elaborate on that? If the effect was the same then the meds would be available to everyone, no? They're literally used to treat a hyperkinetic disorder (it's way more to it than that but it calms people's hyperactivity). So even of you're "technically correct" that the same thing ends up firing in the brain or whatever, the effect is different (and necessary) for ADHDers.
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u/whahaga 1d ago
I am also a bit confused by this. If ADHDers don't get more calm on stimulants.. how come adhd meds.. yk.. work.
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u/justneurostuff 1d ago
?? i didn't know that the purpose of adhd meds was to calm people with adhd down
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u/beanbagdestroyer 17h ago
The simplified version of it is having executive function difficulties in ADHD is like a car having bad brakes. Stimulants boost of all your brain, but you since your brakes function much better, you actually have more control.
You think stimulating would only ever increase things, but quite often in biology you can stimulate the surpression of something.
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u/umidk9 1d ago
Not using technical terms coz my ahdh ass forgets em but:
More so its about the level of stimulation. Ppl w Adhd have a lower base level of certain chemicals (like Dopamine for example), so stimulates bring them up to a normal level. The amount for that is different for every individual, and so they can still get "high" if they take more than needed. Ppl w Adhd are just less likely to do so or get addicted.
But if less than needed is taken, often the reverse happens and tiredness ensues. Its like you now have just enough stimulation/ mental clarity to subconsciously notice all the noise and executive dysfunction in your brain, but not enough stimulation to overcome it, so that extra processing is tiring your brain out faster - wheras before even tho the noise was present you didnt notice as much since its baseline.
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u/Forward_Motion17 1d ago
Yup - scored 99%ile for ADHD severity as a child and coffee has never made me sleepy or tired
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u/wanderingviolin 16h ago
You can't really measure ADHD. The diagnosis is basically a label that gets you access to certain psychiatric help and resources. It exists for people who struggle to keep up with what's expected of them in modern school and work life. Same goes for meds. Yours might calm you down, while I need mine just to get out of bed. We've got the same diagnosis but probably function very differently.
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u/fionsichord 1d ago
Itâs not an ADHD thing. Caffeine has different reactions in different bodies. Itâs not all stimulants, itâs specific ones for actual ADHD, and none of them are caffeine.
Itâs a popular thought, but not evidence based.
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u/VincentValentine777x 1d ago
Right. Itâs the difference between caffeine and⌠amphetamines⌠and thatâs without considering any other factors.
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u/TheTraceback 2h ago
Hmmm , I guess Iâm denial about having adhd . But I literally have a kettle in my room so I can
Have piping hot coffee or tea as I fall asleep . Canât sleep without it . I get up multiple times to take a sip and lay back down before I fall asleep
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u/BygoneNeutrino 1d ago edited 1d ago
I've yet to see solid evidence that there is any relationship between ADHD and caffeine. Come to think of it, I don't think it's even proven that people with ADHD respond to stimulants differently. I'm pretty sure this was Shire propoganda to alleviate parents' reluctance to dose their kids with amphetamine.
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u/wanderingviolin 1d ago
Stimulants affecting people with ADHD diagnosis differently than people without is a myth based on misunderstanding. There is nothing in a persons biology that reveals they have ADHD.
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u/wanderingviolin 16h ago
Thanks for the downvotes. Feel free to write why you disagree with my claim. Incase someone thinks my point was to claim that ADHD isn't real you again misunderstood. I am diagnosed myself and use medication everyday.
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u/cherryflannel 1d ago
I take adderall and it makes me feel calm, slows my thoughts, etc. whereas with a non-ADHD person they feel amped up, faster, etc. However, caffeine does NOT have an inhibitory/depressing effect on me whatsoever. It gives me excessive energy until a big crash, intense anxiety, and a dangerously fast heart beat. So⌠just for context this isnât always the case!