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Any mood or depression study without a control group is, unfortunately, useless.

There is an interesting effect in mood related studies where every group usually improves on average, even if they receive only placebo. The real measure of any depression study is therefore the improvement above and beyond the control group.

The effect is so predictable that it has become an easy way to produce studies showing positive effects from something: All you have to do is track some group of people and then give ALL of them your supplement, and their scores will improve. It makes great headlines because most people don’t know you could have given them sugar pills and the scores would also improve.

EDIT: As another commenter pointed out, this person has an unusual long list of financial affiliations with companies that produce drink products, too. This study should probably be ignored

Also, for anyone who ever tried to quit coffee, probably knows this— the period of feeling down, useless, slow, and tired after you quit is brutal for about 1-2 weeks and can last months for long-time coffee drinkers. No wonder people feel great after having coffee again.

And decaf is not caffeine-free. Decaf coffee still contains about 5-10% of the original caffeine content compared to the same beans but not decaffeinated.

And then there’s the tiny sample size :( and no control group. This is worse than useless. This is the kind of waste that news stations will pick and advertise.

I've quit from daily 3-4 shots of espresso to only drinking it when I feel like it, which is about once every two weeks.

The process was mostly without discomfort: I bought decaf beans and started cutting my coffee grounds with 50% decaf. After two weeks, 75% decaf. Then 87.5%, etc. About two months later I stopped experiencing withdrawals if I don't drink any coffee at all.

Before I started cutting I would get massive headaches and become irritable if I don't drink coffee in the morning. Now I'm free!

I encourage all heavy coffee drinkers try drinking less. At some point, it stops improving your cognitive functions but instead just maintains a mediocre baseline, which I suppose is the same as almost all substance reliance.

> In fact, none of the sleep researchers or experts on circadian rhythms I interviewed for this story use caffeine.

https://www.theguardian.com/food/2021/jul/06/caffeine-coffee...

I noticed from reading threads online that I can drink 8 espressos a day and stop having espresso for several days or weeks. I make my own from ground beans of 18g. It does nothing to me, I never felt a stimulation and only taste guides my need. If I don’t like the taste even offered in restaurant I will refuse to drink it. I don’t know why I’m like that but I never understood the discomfort phases and the stimulation ones either. Idk if I’m missing something
Do you have ADHD (or think you might have?)

If so the difference when you are not drinking coffee might be more disorganisation/inattentiveness/impulsivity etc. rather than being less stimulated.

I have learned that I can have four Aeropress brews per day (about 12.5g coffee per cup) and it makes me calmer, more focussed and more able to be organised. I would notice discomfort and jitters at maybe six in a day. But I can fall asleep an hour after drinking one; it has little effect on my sleep and it may even make it a little easier for me to initially fall asleep.

And then I can have nothing the next day and be fine; I only notice withdrawal on day three maybe.

The reason is, it seems, I have otherwise very unmanaged "inattentive" ADHD. (Which is a stupid name for it; I don't have the slightest problem paying attention to things that capture my interest)

Actually I never felt the need to be diagnosed with ADHD. So I just looked up online and at first-read I don’t think I have something particularly different that could classify me but I might be wrong. Pushing it I also read that there is genetic part to cafein sensitivity but my parents don’t drink coffee at all so I guess I’ll never know. It’s not really a problem though, I can drink double espresso and take a nap or go to sleep which is nice. I can enjoy very good specialty coffee without trouble
I am not a doctor or psychologist or anything so please take everything below with a grain of salt

I was like you in my 20s, I could drink a lot of caffeine without any effects at all. I was diagnosed with ADHD around 28. At the time my doctor told me that my high caffeine intake was maybe an unconscious way of trying to wrangle with my ADHD, because the treatment for that is stimulants.

Once I started my meds, even a low dose, I basically didn't want coffee anymore. It made a huge difference in my life

Not trying to diagnose you with anything, I just always like to tell heavy coffee drinkers my story in case it might help them if they're feeling like something is off

I just volunteered the same suggestion. I am undiagnosed "inattentive" (but it's as obvious as hell, in retrospect) and I clearly self-medicate with caffeine; I used to have an awful coca-cola problem and now in my fifties I like to take a bit of care over my coffee.
It is most probably metabolism/genetics dependent. For me, I didn't have much withdrawals (aside from a first week), but even a month later I was insanely sluggish and it was difficult for me to function properly.
More like 3.75% to 6.6% at most, depending on the bean. But this is not a very good way to think about decaffeination because coffee has to be below 0.1% caffeine by dry weight, regardless of bean, to qualify as decaf, pretty much as a global standard.

A mug of decaf has about 3% of the caffeine of a mug of non-decaf coffee, at most. It is negligible as a stimulant. The only people who would need to avoid it are those with an allergy.

I needed to quit drinking caffeine and my wife decided to just start transitioning me onto decaf without telling me, each week mixing a little more into the regular coffee bean cannister until it was basically 100% decaf. It worked really well, as I didn't find out I'd been drinking 100% decaf until she told me about it.
I had the same process as you (see my comment) and it was much better than quitting it cold turkey.
I agree with all your points, it just leads me to this question: How did this get published in Nature Communications? Surely these are the first things raised by peer review.
That tracks with even decaf coffee having the positive effects in the study.
It's almost like having someone interested in your mental health (even if only to track it) is good for it?
You could be on to something. I mean, how many people might normally rarely get the question "How are you doing?"
"I am fine, thank you. How are you?"
My therapist asked me to track my binge eating episodes, empty log after a week...
Keep tracking and reporting to someone you trust! It can really help to know others are invested in you, whether random internet strangers encouraging you or people in your life you trust.
This effect occurs even in non-mental health related studies.
"J.F.C. [the professor in question] has been an invited speaker at conferences organised by Bromotech, Yakult and Nestle and has received research funding from Nutricia, DuPont/IFF, and Nestle. G.C. has received honoraria from Janssen, Probi, Apsen, and Ingelheim Boehringer as an invited speaker; is in receipt of research funding from Pharmavite, Fonterra, Reckitt, Nestle and Tate and Lyle; and has been paid for consultancy work by Yakult, Zentiva, Bayer Healthcare and Heel Pharmaceuticals. ES has received honorarium from Janssen Sciences Ireland UC. ES also received honorarium from MyNutriWeb for an event that was sponsored by Yakult. This support neither influenced nor constrained the contents of this manuscript. The remaining authors declare no competing interests."

I feel these disclaimers should be posted under every post about nutritional research that's linked on here. Not saying it proves anything in favour or not, but it's good to know who's getting paid to say what.

They should be posted underneath all medical research.
>Participants first abstained from coffee for two weeks before being reintroduced to either caffeinated or decaffeinated coffee in a blinded trial.

So it could easily just be cessation of withdrawal symptoms.

The sentence immediately before the one you quoted notes that there was a group of non-coffee drinkers in the study, and the sentence immediately after states that both groups experienced the positive effects.
Yes, that's how stimulants work. The first hit, after abstinence, is always the best.
Are you replying to the right comment? Or maybe just haven't had your morning coffee yet? ;)

The point I'm making is that a non-coffee drinker won't have "withdrawal symptoms", so OP's suggestion that the beneficial effects they observed were just "cessation of withdrawal symptoms" doesn't make any sense. As in literally nonsense: "a non-coffee drinker's withdrawal symptoms" is nonsensical in the same way the idea of a square circle is.

Well obviously, the study could be bunk, but decaf essentially contains no stimulant, so this isn't really enough to explain the results.
2 weeks isn't long enough to reduce ∆FosB expression after drug (caffeine) use. Most likely I'd say you're right; the subjects are in withdrawal and getting a dose is relaxing.
Adding caffeine pill and placebo pill groups would be interesting.
Only if they hadn't also tested decaf. There's clearly another factor at play.
Note that as the trial is described, the blinding was only related to the presence or not of caffeine. There wasn't any "non-coffee" placebo (something with the taste but none of the components of coffee). (Of course it is certainly difficult to make something taste like coffee while being as neutral as water. I don't even think it is possible.)

As such, the improvement seen when they start drinking coffee could simply be a placebo effect. Coffee making is a nice daily ritual that helps being grounded in the present, as do sents, tastes and the feeling of a warm beverage.

The study is also fairly low power, as you have 62 people in four groups: coffee drinker with caffeine, coffee drinker with decaffeinated, non-coffee drinker with caffeine, non-coffee drinker with decaffeinated.

(Again, a big problem in many human studies is that it is very hard to recruit enough people, both for financial and organization reasons, so don't read this as a knock against the research team).

Hmm is this about caffeine's effect or about going back to caffeine after abstaining from it?

And is the effect chemical, or there's also something about the ritual?

Has anyone compared groups that either drank coffee or took the same quantity in pills?

Well according to the abstract it related to gut health affects of the coffee not the caffeine itself.

> "Our findings reveal the microbiome and neurological responses to coffee, as well as their potential long-term benefits for a healthier microbiome. Coffee may modify what microbes do collectively, and what metabolites they use. As the public continues to think about dietary changes for the right digestive balance, coffee has the potential to also be harnessed as a further intervention as part of a healthy balanced diet."

That would explain why it works for decaf too. i.e. it's healthy gut, healthy mind.

I did some searching as well. This (unrelated to today's article) seems to say the ritual does more than just ingesting the substance:

https://www.medicalnewstoday.com/articles/drinking-morning-c...

The differences found seem more interesting:

>The study also found differences in gut bacteria between coffee drinkers and non-coffee drinkers, including increases in species such as Eggertella sp and Cryptobacterium curtum, which are thought to play roles in gut function and metabolism.

>Cognitive effects varied depending on coffee type: decaffeinated coffee was associated with improvements in learning and memory, while caffeinated coffee was linked to reduced anxiety, improved vigilance and attention, as well as a reduced risk of inflammation.

The actual journal article has a lot more information, the clickbait headline doesn't really do it justice https://www.nature.com/articles/s41467-026-71264-8

I've never been a fan of coffee, but I liked drinking it, but more out of habit than desire, and always at work (rarely at home). Years ago I started to notice terrible headaches on the weekends, and only after a long time did I manage to understand that coffee withdrawal was the cause. For me the conclusion was obvious: I will no longer take something that affects my body at this level. I have the same problem with Coke/Pepsi, I stopped taking it too.

Fun fact: on the same day I noticed and stopped taking it coffee, 5 days later I had terrible muscle pain in my lower back (I could hardly sleep). 2 days later I had no more pain. I researched later and saw that this type of pain could also be caused as an effect of caffeine withdrawal.

Anecdotally, multiple folks have said to me they don't drink coffee because it makes them anxious. Enough for me to take notice.
There might also be adverse effects on one's sleep quality, even if they only drink it in the morning:

> In fact, none of the sleep researchers or experts on circadian rhythms I interviewed for this story use caffeine.

https://www.theguardian.com/food/2021/jul/06/caffeine-coffee...

I'll +1 that, and I'm one of those people but only if I'm already in a poor mental state. When I have something to feel anxious about (e.g, health concerns), then coffee consistently makes me feel more anxious.

Although, it doesn't make me feel anxious on most days, it's really only if I already have a prior reason, it just exacerbates it.

The journal article actually touches on that:

>In CD participants, indoles such as indole-3-propionic acid (IPA) and indole-3-carboxyaldehyde (ICA) and the neurotransmitter γ-aminobutyric acid (GABA) were significantly decreased.

GABA is an anti-anxiety neurotransmitter, it's what benzodiazepines mimic.

Caffeine-induced anxiety disorder is a real thing.
I love coffee, I take 2 to 3 every day (Italian espresso, so very short, little total caffeine), however for some reason taking the decaffeinated one in the evening interferes with my sleep in a similar way than the caffeinated one. Any hint?
> Both groups reported lower perceived stress, depression and impulsivity scores after coffee was reintroduced

This is a terrible sentence. As I understand it, you can't "reintroduce" coffee to non-coffee drinkers.

Is this real, or is this a green jelly bean - https://xkcd.com/882/. Since most Americans (likely including you, though in some countries tea is more popular) are addicted to coffee they like to boost anything that makes their addiction seem like a good thing.