Chloroquine-induced psychosis

In the past few days, a new hot subject has gripped the attention of various media and concerned the medical doctors, as if they don’t have enough to deal with: chloroquine. That is because the President of the U.S.A., Donald Trump, endorsed chloroquine as treatment of COVID-19, a “game changer”, despite his very own director of the National Institute of Allergy and Infectious Diseases (NIAID), Dr. Anthony Fauci, very emphatically and vehemently denying that the promise of (hydroxy)chloroquine is beyond anecdotal (see the White House briefing transcript here).

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Many medical doctors spoke out urging caution against the drug, particularly against the combination the President endorses: hydroxychloroquine + azithromycin. As I understand it, this combo can be lethal as it can lead to fatal arrhythmia.

As for the (hydroxy)cloroquine’s possibility to help treat COVID-19, the jury is still out. Far out. Meaning that there have been a few interesting observations of the drugs working in a Petri dish (Liu et al. 2020, Wang et al., 2020), but as any pharma company knows, there is a long and perilous way from Petri dishes to pharmacies. To be precise, only 1 in 5000 drugs get from pre-clinical trials to approval and it takes about 12 years for this process to be completed (Kaljevic et al., 2004). The time is so long not because red tape, as some would deplore, but because it takes time to see what it does in humans (Phase 0), what doses are safe and don’t kill you (Phase 1), does it work at all for the intended disease (Phase 2), compare it with other drugs and evaluate the long-term side effects (Phase 3) and, finally, to see the risks and benefits of this drug (Phase 4). While we could probably get rid of Phase 0 and 4 when there is such a pandemic, there is no way I would submit my family to anything that hasn’t passed phases 1, 2, and 3. And those take years. With all the money that a nation-state has, it would still take 18 months to do it semi-properly.

Luckily for all of us, chloroquine is a very old and established anti-malarial medicine, and as such we can safely dispense of Phases 0, 1, and 4, which is fine. So we can start Phase 2 with (hydroxy)chloroquine. And that is exactly what WHO and several others are doing right now. But we don’t have enough data. We haven’t done it yet. So one can hope as much as they want, but that doesn’t make it faster.

Unfortunately – and here we go to the crux of the post -, following the President’s endorsement, many started to hoard chloroquine. Particularly the rich who can afford to “convince” an MD to write them a script for it. In countries where chloroquine is sold without prescription, like Nigeria, where it is used for arthritis, people rushed to clear the pharmacies and some didn’t just stockpiled it, but they took it without reason and without knowing the dosage. And they died. [EDIT, 23 March 2020. If you think that wouldn’t ever happen in the land of the brave, think again, as the first death to irresponsible taking chloroquine just happened in the USA]. In addition, the chloroquine hoarding in US by those who can afford it (is about $200 for 50 pills) lead to lack of supply for those who really need it, like lupus or rheumatology patients.

For those who blindly hoard or take chloroquine without prescription, I have a little morsel of knowledge to impart. Remember I am not an MD; I hold a PhD in neuroscience. So I’ll tell you what my field knows about chloroquine.

Both chloroquine and hydroxychloroquine can cause severe psychosis.

That’s right. More than 7.1 % of people who took chloroquine as prophylaxis or for treatment of malaria developed “mental and neurological manifestations” (Bitta et al.,  2017). “Hydroxychloroquine was associated with the highest prevalence of mental neurological manifestations” (p. 12). The phenomenon is well-reported, actually having its own syndrome name: “chloroquine-induced psychosis”. It was observed more than 50 years ago, in 1962 (Mustakallio et al., 1962). The mechanisms are unclear, with several hypotheses being put forward, like the drugs disrupting the NMDA transmission, calcium homeostasis, vacuole exocytosis or some other mysterious immune or transport-related mechanism. Because the symptoms are so acute, so persistent and so diverse than more than one brain neurotransmitter system must be affected.

Chloroquine-induced psychosis has sudden onset, within 1-2 days of ingestion. The syndrome presents with paranoid ideation, persecutory delusions, hallucinations, fear, confusion, delirium, altered mood, personality changes, irritability, insomnia, suicidal ideation, and violence (Biswas et al., 2014, Mascolo et al., 2018). All these at moderately low or therapeutically recommended doses (Good et al., 1982). One or two pills can be lethal in toddlers (Smith & Klein-Schwartz, 2005). The symptoms persist long after the drug ingestion has stopped (Maxwell et al., 2015).

Still want to take it “just in case”?

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P.S. A clarification: the chemical difference between hydroxychloroquine and chloroquine is only one hydroxyl group (OH). Both are antimalarial and both have been tested in vitro for COVID-19. There are slight differences between them in terms of toxicity, safety and even mechanisms, but for the intents of this post I have treated them as one drug, since both produce psychosis.


1) Biswas PS, Sen D, & Majumdar R. (2014, Epub 28 Nov 2013). Psychosis following chloroquine ingestion: a 10-year comparative study from a malaria-hyperendemic district of India. General Hospital Psychiatry, 36(2): 181–186. doi: 10.1016/j.genhosppsych.2013.07.012, PMID: 24290896 ARTICLE

2) Bitta MA, Kariuki SM, Mwita C, Gwer S, Mwai L, & Newton CRJC (2 Jun 2017). Antimalarial drugs and the prevalence of mental and neurological manifestations: A systematic review and meta-analysis. Version 2. Wellcome Open Research, 2(13): 1-20. PMCID: PMC5473418, PMID: 28630942, doi: 10.12688/wellcomeopenres.10658.2 ARTICLE|FREE FULLTEXT PDF

4) Good MI & Shader RI. Lethality and behavioral side effects of chloroquine (1982). Journal of Clinical Psychopharmacology, 2(1): 40–47. doi: 10.1097/00004714-198202000-00005, PMID: 7040501. ARTICLE

3) Kraljevic S, Stambrook PJ, & Pavelic K (Sep 2004). Accelerating drug discovery. EMBO Reports, 5(9): 837–842. doi: 10.1038/sj.embor.7400236, PMID: 15470377, PMCID: PMC1299137. ARTICLE| FREE FULLTEXT PDF

4) Mascolo A, Berrino PM, Gareri P, Castagna A, Capuano A, Manzo C, & Berrino L. (Oct 2018, Epub 9 Jun 2018). Neuropsychiatric clinical manifestations in elderly patients treated with hydroxychloroquine: a review article. Inflammopharmacology, 26(5): 1141-1149. doi: 10.1007/s10787-018-0498-5, PMID: 29948492. ARTICLE

5) Maxwell NM, Nevin RL, Stahl S, Block J, Shugarts S, Wu AH, Dominy S, Solano-Blanco MA, Kappelman-Culver S, Lee-Messer C, Maldonado J, & Maxwell AJ (Jun 2015, Epub 9 Apr 2015). Prolonged neuropsychiatric effects following management of chloroquine intoxication with psychotropic polypharmacy. Clinical Case Reports, 3(6): 379-87. doi: 10.1002/ccr3.238, PMID: 26185633. ARTICLE | FREE FULLTEXT PDF

6) Mustakallio KK, Putkonen T, & Pihkanen TA (1962 Dec 29). Chloroquine psychosis? Lancet, 2(7270): 1387-1388. doi: 10.1016/s0140-6736(62)91067-x, PMID: 13936884. ARTICLE

7) Smith ER & Klein-Schwartz WJ (May 2005). Are 1-2 dangerous? Chloroquine and hydroxychloroquine exposure in toddlers. The Journal of Emergency Medicine, 28(4): 437-443. doi: 10.1016/j.jemermed.2004.12.011, PMID: 15837026. ARTICLE

Studies about chloroquine and hydoxychloroquine on SARS-Cov2 in vitro:

  • Gautret P, Lagier J-C, Parola P, Hoang VT, Meddeb L, Mailhe M, Doudier B, Courjon J, Giordanengo V, Esteves Vieira V, Tissot Dupont H,Colson SEP, Chabriere E, La Scola B, Rolain J-M, Brouqui P,  Raoult D. (20 March 2020). Hydroxychloroquine and azithromycin as a treatment of COVID-19: results of an open-label non-randomized clinical trial. International Journal of Antimicrobial Agents, PII:S0924-8579(20)30099-6, ARTICLE | FREE FULLTEXT PDF

These studies are also not peer reviewed or at the very least not properly peer reviewed. I say that so as to take them with a grain of salt. Not to criticize in the slightest. Because I do commend the speed with which these were done and published given the pandemic. Bravo to all the authors involved (except maybe the last one f it proves to be fraudulent). And also a thumbs up to the journals which made the data freely available in record time. Unfortunately, from these papers to a treatment we still have a long way to go.

By Neuronicus, 22 March 2020

Who invented optogenetics?

Wayne State University. Ever heard of it? Probably not. How about Zhuo-Hua Pan? No? No bell ringing? Let’s try a different approach: ever heard of Stanford University? Why, yes, it’s one of the most prestigious and famous universities in the world. And now the last question: do you know who Karl Deisseroth is? If you’re not a neuroscientist, probably not. But if you are, then you would know him as the father of optogenetics.

Optogenetics is the newest tool in the biology kit that allows you to control the way a cell behaves by shining a light on it (that’s the opto part). Prior to that, the cell in question must be made to express a protein that is sensitive to light (i.e. rhodopsin) either by injecting a virus or breeding genetically modified animals that express that protein (that’s the genetics part).

If you’re watching the Nobel Prizes for Medicine, then you would also be familiar with Deisseroth’s name as he may be awarded the Nobel soon for inventing optogenetics. Only that, strictly speaking, he did not. Or, to be fair and precise at the same time, he did, but he was not the first one. Dr. Pan from Wayne State University was. And he got scooped.98.png

The story is at length imparted to us by Anna Vlasits in STAT and republished in Scientific American. In short, Dr. Pan, an obscure name in an obscure university from an ill-famed city (Detroit), does research for years in an unglamorous field of retina and blindness. He figured, quite reasonably, that restoring the proteins which sense light in the human eye (i.e. photoreceptor proteins) could restore vision in the congenitally blind. The problem is that human photoreceptor proteins are very complicated and efforts to introduce them into retinas of blind people have proven unsuccessful. But, in 2003, a paper was published showing how an algae protein that senses light, called channelrhodopsin (ChR), can be expressed into mammalian cells without loss of function.

So, in 2004, Pan got a colleague from Salus University (if Wayne State University is a medium-sized research university, then Salus is a really tiny, tiny little place) to engineer a ChR into a virus which Pan then injected in rodent retinal neurons, in vivo. After 3-4 weeks he obtained the expression of the protein and the expression was stable for at least 1 year, showing that the virus works nicely. Then his group did a bunch of electrophysiological recordings (whole cell patch-clamp and voltage clamp) to see if shining light on those neurons makes them fire. It did. Then, they wanted to see if ChR is for sure responsible for this firing and not some other proteins so they increased the intensity of the blue light that their ChR is known to sense and observed that the cell responded with increased firing. Now that they saw the ChR works in normal rodents, next they expressed the ChR by virally infecting mice who were congenitally blind and repeated their experiments. The electrophysiological experiments showed that it worked. But you see with your brain, not with your retina, so the researchers looked to see if these cells that express ChR project from the retina to the brain and they found their axons in lateral geniculate and superior colliculus, two major brain areas important for vision. Then, they recorded from these areas and the brain responded when blue light, but not yellow or other colors, was shone on the retina. The brain of congenitally blind mice without ChR does not respond regardless of the type of light shone on their retinas. But does that mean the mouse was able to see? That remains to be seen (har har) in future experiments. But the Pan group did demonstrate – without question or doubt – that they can control neurons by light.

All in all, a groundbreaking paper. So the Pan group was not off the mark when they submitted it to Nature on November 25, 2004. As Anna Vlasits reports in the Exclusive, Nature told Pan to submit to a more specialized journal, like Nature Neuroscience, which then rejected it. Pan submitted then to the Journal of Neuroscience, which also rejected it. He submitted it then to Neuron on November 29, 2005, which finally accepted it on February 23, 2006. Got published on April 6, 2006. Deisseroth’s paper was submitted to Nature Neuroscience on May 12, 2005, accepted on July, and published on August 14, 2005… His group infected rat hippocampal neurons cultured in a Petri dish with a virus carrying the ChR and then they did some electrophysiological recordings on those neurons while shining lights of different wavelengths on them, showing that these cells can be controlled by light.

There’s more on the saga with patent filings and a conference where Pan showed the ChR data in May 2005 and so on, you can read all about it in Scientific American. The magazine is just hinting to what I will say outright, loud and clear: Pan didn’t get published because of his and his institution’s lack of fame. Deisseroth did because of the opposite. That’s all. This is not about squabbles about whose work is more elegant, who presented his work as a scientific discovery or a technical report or whose title is more catchy, whose language is more boisterous or native English-speaker or luck or anything like that. It is about bias and, why not?, let’s call a spade a spade, discrimination. Nature and Journal of Neuroscience are not caught doing this for the first time. Not by a long shot. The problem is that they are still doing it, that is: discriminating against scientific work presented to them based on the name of the authors and their institutions.

Personally, so I don’t get comments along the lines of the fox and the grapes, I have worked at both high profile and low profile institutions. And I have seen the difference not in the work, but in the reception.

That’s my piece for today.

Source:  STAT, Scientific American.


1) Bi A, Cui J, Ma YP, Olshevskaya E, Pu M, Dizhoor AM, & Pan ZH (6 April 2006). Ectopic expression of a microbial-type rhodopsin restores visual responses in mice with photoreceptor degeneration. Neuron, 50(1): 23-33. PMID: 16600853. PMCID: PMC1459045. DOI: 10.1016/j.neuron.2006.02.026. ARTICLE | FREE FULLTEXT PDF

2) Boyden ES, Zhang F, Bamberg E, Nagel G, & Deisseroth K. (Sep 2005, Epub 2005 Aug 14). Millisecond-timescale, genetically targeted optical control of neural activity. Nature Neuroscience, 8(9):1263-1268. PMID: 16116447. DOI: 10.1038/nn1525. doi:10.1038/nn1525. ARTICLE 

By Neuronicus, 11 September 2016