References
- Hartman & Hollister 1963 – Effect of mescaline, LSD and psilocybin on color perception
- Abraham 1982 – A chronic impairment of colour vision in users of LSD
- Anthony et al. 2020 – Improved colour blindness symptoms associated with recreational psychedelic use: Results from the Global Drug Survey 2017
- Barnett et al. 2023 – Case report: Prolonged amelioration of mild red-green color vision deficiency following psilocybin mushroom use
A note on Barnett et al. 2023
2 days after I first recorded this video back in May, this paper was published looking at the effects of psilocybin on a color blind subject. I spent 2 months thinking about how I was going to shoehorn this new paper into the video, but ultimately realized that if I didn’t just published this video without it, I probably never would, but I still want to address it. Anyway, here is the new paper:
https://journals.sagepub.com/doi/10.1177/20503245231172536
“Case report: Prolonged amelioration of mild red-green color vision deficiency following psilocybin mushroom use”
In this study, a deuteranomalous man dosed on magic mushrooms, and measured his color vision using the Ishihara test directly before, directly after, and at several intervals up to more than a year later. The results show slight increases to his ishihara scores, which never clearly identified him as actually being deuteranomalous.
Through misspelling deuteranomaly (deuteranomalia, archaic) and misunderstanding the mechanisms behind deuteranomaly (claiming damaged cones instead of shifted spectral sensitivity), it is likely that the authors’ backgrounds are not in color vision. Otherwise, they would probably be familiar with the faults of the Ishihara and why it is a poor test for quantifying color vision, in part because it is trainable, i.e. scores are expected to increase the first few times you take the test as you understand certain minutia and tricks of the test, plus you start to memorize the answers. Even if you don’t have the answer key, changes in lighting or color adaptation from test to test (indicative of a subject selftesting), will favour some plates some days and some plates other days. So even if you can’t really see plate C on thursday, the fact that you saw it on Monday and got it right, may be enough to help you ‘guess’ it on Thursday.
The author’s are good to point out many of the other faults of the methodology, but these faults are fatal in my eyes. Controlled testing would really be necessary to draw ANY conclusions here. The author’s don’t exactly give much discussion on possible mechanisms. They mostly defer to the Anthony et al. [2020] paper discussed in the video, but also hold reservations about their neuroplasticity explanations. I wont fault the 2023 authors as much as the 2020 authors, but I don’t believe their results are any more compelling.
Transcript + Footnotes
Psychedelics can make you “see” pretty colors, but what are they ACTUALLY doing for your color vision?
Today on Chromaphobe… can hallucinogens, psychedelics, LSD, shrooms… improve your color vision or help your colorblindness?
ANECDOTES
There are plenty of observations that seem to suggest this, and it’s not just your stoner roommate, its famous stoners like author Aldous Huxley, who claimed:
“Mescalin raises all colours to a higher power and makes [me] aware of innumerable fine shades of difference, to which, at ordinary times, [I am] completely blind.”
Or Bill Wilson, the founder of alcoholics anonymous:
“…the LSD experience has helped me very much. I find myself with a heightened color perception and an appreciation of beauty almost destroyed by my years of depression…”
But no, I get it, these guys aren’t like… ophthalmologists or anything… here’s someone a bit more authoritative on whether hallucinogens can alleviate colorblindness… reddit user u/threesixzero, who “um actually’d”:
“Many colorblind people can see colors while tripping on shrooms and LSD. It has been widely reported, google it…”
Yeah! Lets google some of that… science! But because chromaphobe is a legitimate science-based channel, we don’t use google… we use google scholar.
The first paper that comes up happens to be one of the darlings of the pro-psychedelic community, titled “Improved colour blindness symptoms associated with recreational psychedelic use”… and I hate it.
But before we look at what’s inside, can we all appreciate how awesome your lab must be when your lead principal investigator is literally named DJ NUTT… DDDDJ NUUUUTTT… *sploodge*
Okay enough of that… because this is a serious academic paper, which has recently been referenced EXTENSIVELY as proof that LSD alleviates colorblindness, by 100% legitimate and trustworthy news organizations by the way, like:
Each of them offering sensationalized headlines like: “Could psychedelics cure color blindness?” or “Are You Color Blind,Try Magic Mushrooms!”
Footnote 1
As a scientist, this paper is a little insulting and I’m surprised it got published at all, it’s pretty bad science… but as a colorblind guy… its also a little insulting. Because every minor benefit to aesthetic color vision that the colorblind receive from the hallucinogens:
the distorted colors,
the potential ability to see impossible colors,
The ambiguously “enhanced” aesthetic…
They all apply equally to color normals, but the authors don’t say the drugs are somehow “alleviating the symptoms” of having normal color vision, or alleviating the symptoms of not being a tetrachromat.
It probably won’t surprise you that this is not the conclusion of the paper whatsoever, but… that’s just those microdosebros doing what those microdosebros doze… does.
So not only do the popsci articles greatly extrapolate the conclusions of the researchers, but the actual evidence used by the original researchers… is about as weak as evidence can get…
As part of the 2017 Global Drug Survey – an annual questionnaire completed by over 100’000 recreational drug users – the following question was given:
“We have received reports from some people with colour-blindness that this improves after they use psychedelics. If you have experienced such an effect can you please describe it in the box below, say what drug you took and how long the effect lasted.”
Having collected 382 responses, the authors found 47 of those anecdotes “useful”, and from those 47, half of them indicated some “favorable” change to color vision. They then applied the controversial maxim that “the plural of anecdote is data”, concluding that psychedelics not only enhance color vision during the trip, but also enhance color vision in the long term… The question is… how?
Footnote 2
While a survey is the weakest form of evidence, all studies generally have to start *near* the bottom of this list before it can eventually be studied enough to warrant the higher levels of analysis. However, a paper is generally not written already at the survey level, since conclusions can not typically be drawn from survey data. The bigger problem with this survey is the poorly phrased question that only asks people to respond if they had a positive experience, introducing a large selection bias, then later compares the number of positive to non-positive (neutral or negative) responses. Then 88% of responses are rejected for not being useful, but no indication is given for what that means.
MECHANISM
Just so we’re on the same page… I am colorblind – like “most” others – because I’m missing a gene that encodes one of my opsin proteins, one of the light sensitive receptors in the retina. Where most people have 3 different opsin genes, we colorblind only have 2.
Footnote 3
What’s described in the video is dichromacy, including protanopia and deuteranopia, where one of the three cones is absent. Dichromacy makes up about a quarter of color blind cases. The other three quarters is all anomalous dichromacy, a less severe form of color blindness, including protanomaly and deuteranomaly. In those cases, the three cones are still present, but they are shifted in the spectrum, which reduces the sensitivity of red-green color discrimination. Importantly to this analysis, that reduction in sensitivity is also 100% genetic, so cannot be undone with hallucinogens for the same reasons described in the video.
Do the psychedelics help the colorblind overcome this very fundamental shortcoming? Do magic mushrooms somehow alter my DNA? Of course not… and the authors acknowledge this when they say:
“Psychedelics will not alter the inherent colour sensing ability of the optical machinery in the retina;”
So they agree, they can’t improve color blindness at a…
“-however, [psychedelics] may affect central processing of the colour signal from the retina thus affecting colour blindness.”
uuuuuugh…
Now let me rephrase their logic… um… in my own words:
“We know that congenital colorblindness is associated solely with the cones in the retina, but LSD does a whole bunch of weird brainy stuff, so… LSD cures colorblindness!”
NEUROPLASTICITY
Alright, a little less snarky… the paper’s argument can be summed up in one word… neuroplasticity… the idea that your brain – when under the influence – is able to make new connections and therefore overcome any kind of neurological or psychological deficiency.
I absolutely recognize that psychedelics are likely effective at treating depression or PTSD, but colorblindness in almost all cases is neither psychological nor strictly neurological. It is not something that can be addressed by changing any part of your connectome – that is, the wiring diagram of your brain.
Footnote 4
Cerebral achromatopsia is a neurological disorder that causes color blindness, but is very rare. While unlikely that hallucinogens can alleviate the symptoms of cerebral achromatopsia, it is at least more plausible than them alleviating the symptoms of genetic red-green color blindness. In the video I say that red-green color blindness is not neurological, but as the affected cone cells technically are neurons, the opposite could be argued. However, the important distinction here is that hallucinogens cannot have a direct effect in the retinal neurons, despite technically being a part of the central nervous system, because serotonin – the neurotransmitter affected by LSD, for example – is not used in the retina.
The authors correctly recognize that the perception of colors is not based solely on the cones in your retina, but on several regions of the visual cortex in the brain. And hell, it’s common knowledge that psychedelics DO positively “affect” your perception of color. I can attest!
“Ugggh, kids these days and their drugs”
Oh, and we’re supposed to believe that world famous victorian era chemist John Dalton wasn’t binging daily on opium? Right. It’s okay to slander the dead, right?
Anyway, Psychedelics alter the processing of color in your visual cortex… in your brain. *sigh* So where is the disconnect between “affecting your color vision in a positive way” and “having no effect on your colorblindness”?
COLOR TASKS
Let’s talk about color tasks. Discussions around this subject revolve around words like “improving” or “enhancing” color vision. But while you may have an INTUITIVE understanding of what those mean… intuition and drugs are a dangerous combination. If you were to see the world like a Lisa Frank print, would that be *improved* color vision? Is seeing a tiger with bright purple fur… an enhancement?
Well, it can be.
Obviously color vision…. Little bit complicated, so let’s get a little more specific. Every way we interact with color can be categorized into 4 tasks.
- Comparative – discern if two colors are the same, and if different, how different they are.
- Denotative – relate a color to its name
- Connotative – relate a color to some cultural meaning like “pink means feminine”, and
- Aesthetic – which is the hardest to explain, but any “task” that involves the visual appreciation of color and color palettes.
So “enhancing” color vision by enhancing the aesthetic appreciation of color is absolutely a valid interpretation of enhanced color vision, and I don’t think anyone would argue that psychedelics don’t give you an enhanced aesthetic. Heck, many believe that psychedelics can let you see brand new colors.
IMAGINARY COLORS
As the Global Drug Survey paper put it:
“…the notion of a new colour being experienced under the influence of psychedelic drugs is not unfathomable.”
And yeah, I can fathom that. A brain on psychedelics intercepts that retinal signal and distorts it, such that the signal evokes the idea… the IDEA… of a different color. In extreme cases, the signal can be distorted to such a degree that the evoked color is otherwise impossible to experience in normal conditions.
These colors are broadly called impossible colors, and one subset of impossible colors are imaginary colors. Think of imaginary colors this way… Pure 400nm light excites only the blue cone and evokes pure violet. Pure 700nm light excites only the red cone and evokes pure red. So what wavelength of light can excite only the green cone? There isn’t one. All visible wavelengths of light always excite either the S or L cone. So, using light alone, the M-cones cannot be excited by themselves, no matter how you pre-filter the light.
But what if we were able to distort that optical signal after it reaches the brain… like, with LSD… turn the L- and S- signals down to 0 such that only the M-cone signal was excited? The evoked color is called hyper-green…. An imaginary color. If we look at our chromaticity diagram, hyper greens reside in this space outside of the spectral locus, because we can’t see them, per se.
Obviously, I’m not a neurologist, but I do believe that such an imaginary color could hypothetically be experienced on psychedelics. Or hell, let’s ask an actual neurologist…
You may recognize Oliver Sacks as the author of Island of the Colorblind, a book and BBC TV special exploring a population of fully-colorblind achromats on the tiny pacific island of Pingelap, but he actually has several essays exploring color and hallucinogens. One of his anecdotes from his 2012 book Hallucinations is particularly appropriate:
In 1965, doubtful of the actual existence of indigo, Sacks gobbled a bunch of hallucinogens and willed himself to see indigo, which apparently manifested as a color he had never truly experienced before. He spent the next 50 years trying to experience Indigo again, unsuccessfully.
Sacks believed he hallucinated a color he’d never seen before, but he also deferred to famous Scottish philosopher David Hume, who, in 1739, introduced the thought experiment The Missing Shade of Blue, arguing that we cannot imagine a color we have never directly perceived.
I am neither neurologist nor philosopher. Did Oliver Sacks really perceive a novel color when on LSD? Well… I’d argue its not really important, because I’d say it unequivocally “enhanced” his color vision in the aesthetic sense… but did it enhance his functional color vision? Could it have alleviated the symptoms of colorblindness?
COMPARATIVE
Taking another look at the 4 color tasks, color blindness is primarily explained through the effects on the COMPARATIVE task, the ability to tell if two colors are the same or different. Two colors that look distinct to a color normal observer can look metameric – or identical – to a colorblind person.
So I would compare them differently than my wife would, meaning I suck at comparative color tasks. Can hallucinogens “enhance” my color vision with regards to comparative color tasks? Alleviate my colorblindness?
Say I’m looking at a field of blue and purple, blue on the left, purple on the right. For the color normals, I’ll make the bottom half of the screen a simulation, so you can see the colors indeed look identical to us…
When these colors hit a normal retina, they get converted into tristimulus values. All the nuances of the light spectrum get condensed into three values, represented by the fullness of the circles. Blue and purple have different tristimulus values, so are perceived as different colors.
When these colors hit a colorblind, dichromatic retina, they get condensed into 2 values. Blue and purple have the same di-stimulus values, so look identical.
By the time the signal encoding those colors is leaving my retina, they are indistinguishable, a single color. There is nothing my brain can do to accurately separate those two colors since it sees them as the same input.
At best, a hallucinating brain will try to notice some non-chromatic difference between the two colored regions, like… a texture… and emphasize that chromatically by distorting the colors of the textured side until it’s different… different, not correct.
Or even more likely, the psychedelic brain will apply a color distortion completely independent of any real differences between the two colors, like showing you a differently-colored blob, that has no relation to the true boundary between the two colors.
It may look interesting, giving you some aesthetic boost, but, none of these distortions will help you accurately compare the two colors, know whether the colors are the same or different, and they certainly won’t help you name those colors correctly.
So I’d argue, that a definition of FUNCTIONALLY enhanced color vision – especially as it relates to colorblindness – should be whether you are more able to differentiate two colors that were previously metameric, that is, two colors that looked the same, but on LSD, look consistently and accurately like different colors.
Luckily, we’ve done this. Let’s look at some more science.
WORSENING
A 1982 study by Abraham tested the color vision of 46 LSD users several months to years after their last trip and actually found that their color vision was WORSE than a control group. It turns out, LSD, like many other pharmaceuticals… takes a chronic toll on your color vision.
However, this study – despite being performed in an era that had access to so many great standard color vision tests – used possibly the worst color vision test I’ve ever heard of – not just from academia – but… ever. [see Footnote 5]
Footnote 5
On the really bad colorblind exam from [Abraham 1982]:
“Each subject was placed 500 centimetres from the test object [(a color lithograph)] and asked to describe with a single word the colour of the “sun, and not the glow around it”. If the subject reported any colour other than white, he was asked to take a step closer and try again. The distance from the picture to the corneas was measured in centimetres when the subject first made the correct response.”
There are several terrible flaws in this method:
- This is a denotative task, which means there is an influence of language.
- The question can be answered connotatively, i.e. people know what color the sun is likely to be (e.g. not green).
- Prompting ‘not the glow around it’ infers that the correct color (white) is different from the glow around the sun.
- All colors that appear white to a color normal will also appear white to a color blind subject. A subject reporting the white sun as colorful does not indicate a typical color vision deficiency. If anything, it indicates a problem with color constancy or other factors, but this has nothing to do with typical color blindness.
- Ending the test once the subject answers correctly is very susceptible to noise from guessing colors, which is important when the test is only given once..
- This test can only be administered to a specific subject one time before they have likely “figured it out”.
All in all, it would be difficult to design a worse test for color vision, so I can’t consider the conclusions of this paper.
If we want GOOD science, then we have to go even further back to a 1963 study by Hartman and Hollister that actually measured color vision of subjects before and during hallucinogenic trips. They used the rather sensitive Farnsworth 100-Hue test to measure a change of color discrimination ability. The 100-Hue test is appropriate here because it is a COMPARATIVE test. It gets rid of as many confounding factors as possible.
Give someone a denotative test like “what color is this toy?” and you are testing language ability as well as color vision. Give someone an aesthetic test like “does this picture look prettier now?” and you are mixing all sorts of other confounding social factors in with the color vision test. That’s why all color vision tests for the last century have been purely comparative.
While this well-designed 1963 paper found very strong indications of synesthesia, where non-chromatic stimuli can evoke colors, they also found that for all their psychedelic drugs, the errors in the 100-Hue test got higher… meaning that psilocybin, mescaline and LSD all made color vision WORSE.
ANY DRUGS?
The next question is, are there ANY drugs that can enhance your color vision, make you more astute at comparative color tasks?
Unlikely. I could not find any evidence or theory of pharmacological methods to increase your ability to discriminate colors, nothing that could shrink your MacAdam ellipses or decrease your just-noticeable-difference in color discrimination, and therefore nothing that can improve colorblindness.
Footnote 6
MacAdam ellipses are regions drawn on a chromaticity diagram, where all the colors contained in the ellipse appear as the same color to a subject. The smaller these ellipses, the fewer colors look the same, and therefore the more colors the subject can differentiate. MacAdam ellipses of red-green colorblind subjects are elongated in the ~vertical direction. In general, the smaller the ellipses, the better the color vision. The just noticeable difference is a similar concept used in psychophysics, where the chromatic “distance” between two colors is increased until those colors become noticeably different. The smaller this value, the better the color vision.
Quite on the contrary actually, there are hundreds of drugs – here are a few – that do exactly the opposite, giving color vision side effects. So far, photobiomodulation – something I investigated in a previous video – is the only thing that even comes close to improving color vision non-surgically, and that has very narrow applicability.
GENE THERAPY
In all this naysaying though, there is one area that I feel is very promising that I haven’t seen anyone discuss yet when it comes to psychedelics and color. Last year, I made a video about Gene Therapy, the only VIABLE cure for colorblindness. Gene therapy introduces missing genes into the retina of colorblind subjects.
As of yet, the procedure has two main problems:
- Its very invasive, which introduces lots of risk
- Its not effective for adult subjects because adult brains are too rigid to be able to rewire themselves to adapt to the new color vision sensations.
You see where this is going… If we were to pair gene therapy with psychedelics to re-plasticize the brain, we may have a winning combination that greatly improves the efficacy of the procedure, meaning that the psychedelics could be a PART of a cure for colorblindness, just not in the way the Micro Dose Bros seem to think.
CONCLUSION
For the rest of us not undergoing gene therapy, psychedelics will do nothing but make your color vision worse.
Absolutely, I believe when the colorblind – or anyone – claim to see new and fascinating colors when taking hallucinogens, this is exactly why we saw positive anecdotes on color vision in the Global Drug Survey!
But this has nothing to do with “improved color blindness symptoms”, because all of the color mistakes you make sober, you will still make when high, and then some. Taking LSD may make you see a beautiful octopus in this Ishihara plate, but that won’t help you pass the test, when the answer is 74. Let me leave you with another testimonial that I think will help us come down from this trip, from redditor u/Mannzis:
“I’m partially colorblind and was convinced I could see all sorts of colors I could not normally see while on acid. I took the test for colorblindness to prove I was right, and I failed it. I just thought I was seeing extra colors. LSDs a hell of a drug, but it can make you think it gives you powers that you don’t in fact have.”
This is chromaphobe.
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