Round trip ticket to the science of psychedelics

The latest edition of The Psychologist is a special open-access issue on the science and social impact of hallucinogenic drugs.

There’s an article by me on culture and hallucinogens that discusses the role of hallucinogenic drugs in diverse cultures and which also covers how cultural expectations shape the hallucinogenic experience – from traditional Kitanemuk society to YouTube trip videos.

The other articles cover some fascinating topics.

Neuroscientists Robin Carhart-Harris, Mendel Kaelen and David Nutt have a great article on the neuroscience of hallucinogens, Henry David Abraham discusses hallucinogen persisting perception disorder or post-trip flashbacks, and there’s also piece that talks to a researcher, participant and clinician on the use of psilocybin to alleviate cancer anxiety, while Keith Laws discusses an intense painting and its psychedelic aspects.

There’s also an excellent piece on the influence of psychedelic drugs on literature from Dirk Hanson – long-time writer of the essential drug blog Addiction Inbox, and Mo Costandi (who you may know from the Neurophilosophy blog) has written a fantastic retrospective of the use of psychedelics in psychiatry.

Overall, a fascinating read and well worth checking out.

Link to special issue of The Psychologist on hallucinogens.

Drugs in space and sleepless in the shuttle

A fascinating study published in today’s Lancet Neurology reports on sleep deprivation in astronauts but also describes the drugs shuttle crew members use to keep themselves awake and help them fall asleep.

The study looked at sleep data from 64 astronauts on 80 space shuttle missions along with 21 astronauts on 13 International Space Station missions, and compared it to their sleep on the ground and in the days before space flight.

Essentially, in-flight astronauts don’t get a great deal of shut-eye, but what’s surprising is the range and extent of drugs they use to manipulate sleep.

Mostly these are the z-drug class of sleep medications (of which the best known is zolpidem, branded name Ambien) but also include benzos, melatonin and an antipsychotic called quetiapine.

Here are the sleep-inducing drugs with my comments in square brackets:

Zolpidem and zolpidem controlled release were the most frequently used drugs on shuttle missions, accounting for 301 (73%) and 49 (12%) of the 413 nights, respectively, when one dose of drug was reported. Zaleplon use was reported on 45 (11%) of 413 nights.

Other sleep-promoting drugs reported by shuttle crew members during the 413 nights included temazepam [sedative anti-anxiety benzodiazepine – similar to Vallium] on 8 (2%) nights, eszopiclone on 2 (<1%) nights, melatonin [hormone that regulates circadian rhythms] on 7 (2%) nights, and quetiapine fumarate [antipsychotic] on 1 (<1%) night.

The paper also notes concerns about the astronauts’ use of zolpidem and similar z-drug medications because they can affect mental sharpness, coordination and can lead to unusual and complex ‘sleep-behaviours’.

Interestingly, it seems astronauts tend to use these drugs in a rather ad-hoc manner and the consequences of this have clearly not been well thought through.

As the Lancet Neurology paper notes:

This consideration is especially important because all crew members on a given mission might be taking a sleep-promoting drug at the same time…. crew members reported taking a second dose of hypnotic drugs—most commonly zolpidem—often only a few hours before awakening. Although crew members are encouraged to try such drugs on the ground at home at least once before their use in flight, such preparations probably do not involve multiple dosing or dosing with two different drugs on the same night.

Furthermore, such tests do not include any measure of objective effectiveness or safety, such as what would happen in the case of abrupt awakening during an in-flight night-time emergency… sleep-related-eating, sleep-walking, and sleep-driving events have been reported with zolpidem use, leading the FDA to require a so-called black-box warning on all hypnotic drugs stating that driving and performance of other tasks might be impaired in the morning after use of such drugs:

“A variety of abnormal thinking and behavior changes have been reported to occur in association with the use of sedative/hypnotics…. Complex behaviors such as ‘sleep-driving’…have been reported. Amnesia, anxiety, and other neuropsychiatric symptoms may occur unpredictably.”

However, use of sleep drugs was reported on more than half the nights before extravehicular activities were undertaken.

Information on stimulant use by astronauts is hidden in the appendix but caffeine was widely used in space, but less than when on the ground – although possibly due to coffee shortages, and modafinil was used occasionally.

Caffeine was widely used throughout all data collection intervals by both shuttle and ISS crewmembers, though supply shortages sometimes led to coffee rationing and reduced consumption aboard ISS. All but eight shuttle mission crewmembers (72/80, 90%) and all but one ISS crewmember (20/21,95%) reported using caffeine at least once during the study…

Given the 3-7 hour half-life of caffeine and the sleep disturbances associated with its use, caffeine may have contributed to or enabled the sleep curtailment observed in this population. However, there is no evidence that caffeine accounts for the reduced sleep duration observed during spaceflight, as caffeine consumption was, if anything, reduced during spaceflight.

The wakefulness-promoting medication, modafinil, was reportedly used on both shuttle (10 reported uses) and ISS missions (2 reported uses). The use of this wakefulness-promoting medication was reported more frequently in post-flight debriefs.

There’s also an interesting snippet that gives the most common reason for sleep disturbance in space:

Nocturnal micturition is common in this age group and was the most reported reason for disruptive sleep both on Earth and inflight

Not stress, not being surrounded by equipment, not a lack of home comforts, but ‘Nocturnal micturition’ or wetting yourself in your sleep.

This is possibly more likely in space due to the fact that bodily cues for a full bladder work less effectively in zero gravity, but one major factor in astronauts wetting themselves was that it a better alternative than waking sleeping colleagues by going to the toilet.

The paper notes that this is why many astronauts wear ‘maximum absorbency garments’ – essentially giant nappies – while they sleep.

Link to locked Lancet study on sleep in astronauts.

Out on a limb too many

Two neuropsychologists have written a fascinating review article about the desire to amputate a perfectly healthy limb known variously as apotemnophilia, xenomelia or body integrity identity disorder

The article is published in the Journal of Neuropsychiatric Disease and Treatment although some who have these desires would probably disagree that it is a disease or disorder and are more likely to compare it to something akin to being transgender.

The article also discusses the two main themes in the research literature: an association with sexual fetish for limb aputation (most associated with the use of the name apotemnophilia) and an alteration in body image linked to differences in the function of the parietal lobe in the brain (most associated with the use of the name xenomelia).

It’s a fascinating review of what we know about this under-recognised form of human experience but it also has an interesting snippet about how this desire first came to light not in the scientific literature, but in the letters page of Penthouse magazine:

A first description of this condition traces back to a series of letters published in 1972 in the magazine Penthouse. These letters were from erotically-obsessed persons who wanted to become amputees themselves. However, the first scientific report of this desire only appeared in 1977: Money et al described two cases who had intense desire toward amputation of a healthy limb. Another milestone was a 2005 study by Michael First, an American psychiatrist, who published the first systematic attempt to describe individuals who desire amputation of a healthy limb. Thanks to this survey, which included 52 volunteers, a number of key features of the condition are identified: gender prevalence (most individuals are men), side preference (left-sided amputations are most frequently desired), and finally, a preference toward amputation of the leg versus the arm.

The review also discusses a potentially related experience which has recently been reported – the desire to be paralysed.

If you want a more journalistic account, Matter published an extensive piece on the condition last year.

Link to scientific review article on apotemnophilia / xenomelia.
Link to Matter article.

A forest of porous dreaming

A fascinating section of the book How Forests Think by anthropologist Eduardo Kohn where he describes how dreaming is much more porous among the Runa people of Ecuador.

This is both because of how they understand dreams, but also because of the way sleep happens in their culture – it being a more social and frequently interrupted activity, meaning that dreams and the outside world interact much more intensely.

From page 13:

Sleeping in Ávila is not the consolidated, solitary, sensorially deprived endeavour it has often become for us. Sleep – surrounded by lots of people in open thatch houses with no electricity and largely exposed to the outdoors – is continuously interspersed with wakefulness. One awakens in the middle of the night to sit by the fire and ward off the chill, or to receive a gourd full of steaming huayusa tea, or on hearing the common potoo call during a full moon, or sometimes the distant hum of a jaguar. And one awakens also to the extemporaneous comments people make throughout the night about those voices they hear.

Thanks to these continuous disruptions, dreams spill into wakefulness and wakefulness into dreams in a way that entangles both. Dreams – my own and those of my housemates, the strange ones we shared, and even those of their dogs – came to occupy a great deal of my ethnographic attention, especially because they so often involved the creatures and spirits that people the forest. Dreams too are part of the empirical, and they are kind of real. They grow out of and work on the world, and learning to be attuned to their special logics and their fragile forms of efficacy helps reveal something about the world beyond the human.

Interestingly, if your sleep is interrupted by people giving you huayasa tea you are also likely to sleep rather differently as it contains caffeine, meaning you may sleep more lightly and be more sensitive to your environment as a result.

I’m still getting to grips with the book which sounds lovely but is actually about how the theory of anthropology as a study of humans is challenged by societies where whole ecosystems form part of cognitive systems.

As with any book about deep theory, it is both difficult and intriguing, and sometimes I feel like I am lost in a forest myself.

Link to more details of How Forests Think.

The genes are to blame game

The media love ‘your genes are to blame’ stories despite the fact that genetics is, in most cases, just one, often small, influence on a behaviour or trait.

Here’s a few lowlights:

Glass always half-empty? Your genes may be to blame
Lazy? Your Genes May Be to Blame
Have math anxiety? Your genes may be to blame
Couch potato? Your GENES could be to blame
Are You Forgetful? Your Genes Might Be To Blame
Are your genes to blame for not being rich?
Can’t do well in exams? Your genes are mostly to blame
Are Genetics to Blame for Poor Driving?
Genes to blame for boozy night

Spoiler: your genes are not to blame.

Firstly, it’s interesting that these stories are almost always framed around difficulties or negative characteristics. Rarely do you read stories along the lines of ‘Good looking? Compassionate? Healthy? Your genes may be to blame’.

In other words, they rely on people’s interest in discounting negative characteristics about themselves to attract readers / advertising targets at the expense of biasing the sorts of scientific results that get media attention.

So here would be a a more accurate if not slightly less catchy version of all these headlines: ‘Have this specific trait or behaviour? Your genes may typically contribute a small to moderate amount to the difference between people if you are similar to the population used in the study to estimate this effect – bearing in mind the caveats about the need to independently replicate the results to be confident in the reliability of the conclusions’

Yes, it doesn’t have quite the same impact as the ‘blame your genes’ headlines but you can still illustrate it with a stock photo of a blonde girl with an exaggerated expression of frustration on her face. Not all bad news, is it editors?

It’s worth saying that these sorts of stories are almost always about traits or behaviours where genetics contributes only a partial amount to the overall outcome but this is not a feature of genetics per se, it depends on what you’re looking at.

On one end of the spectrum are highly penetrant single gene disorders like Huntingdon’s disease where if you have the gene you’ll get the disorder. On the other end are much of human behaviours and traits where there are likely many genes that contribute a varying amount indirectly to the overall difference depending on the population being studied.

No-one has yet done a study on genetic contributions to differences in the likelihood of writing ‘your genes are to blame’ stories – probably due to a fear of opening a recursive media loop from which we may never emerge.

Stroop: an unrecognised legacy

The man who discovered the Stroop effect and created the Stroop test, something which is now a keystone of cognitive science research, never realised the massive impact he had on psychology.

A short but fascinating news item from Vanderbilt University discusses its creator, the psychologist and preacher J. Ridley Stroop.

J. Ridley Stroop was born on a farm 40 miles from Nashville and was the only person in his family to attend college. He began preaching the gospel when he was 20 years old and continued to do so throughout his life. He spent nearly 40 years as a teacher and administrator at David Lipscomb College, now Lipscomb University, in Nashville….

According to his son, Stroop was unaware of the growing importance of his discovery when he died in 1973. Toward the end of his life, he had largely abandoned the field of psychology and immersed himself in Biblical studies. “He would say that Christ was the world’s greatest psychologist,” Faye Stroop recalled.

The task is very simple and relies on the fact that we automatically process word meaning when we see words. We don’t have to recognise each letter, consciously string them together, and ‘work out’ what word it is, it just happens straight away.

Stroop’s insight was to wonder what would happen if he asked people to do something that directly conflicted with this automatic processing.

So if I ask you to name the colour the following word is written in: blue; or name the colour this word is written in: red; you do it a little more slowly than naming the colour that these words are written in: blue, red.

This is because you have to inhibit or consciously ‘get round’ the word’s automatically recognised meaning.

This inhibition of automatic responses turns out to be a key function of attention and is heavily linked to the workings of the pre-frontal cortex.

There are many variations, all based on the fact that word meanings can relate to many different forms of psychological process, bias or experience.

For example, the ‘emotional Stroop‘ asks people to name the ‘ink colour’ of either emotionally neutral words (like ‘apple’, ‘soap’) and more emotionally intense words (like ‘violence’ or ‘torture’).

People who have been traumatised, will be more affected by these sorts of emotionally intense words and so they will identify the ‘ink colour’ of trauma-related words more slowly than when compared to non-traumatised people.

The same happens for people with spider phobia when they read spider-related words, and so on.

And because it allows experimenters to measure the interaction between attention and meaning, it has become a massively useful and popular tool.

Link to piece on the history of the Stroop task.

A multitude of phantoms

A fascinating paper in the neuroscience journal Brain looks at artistic depictions of phantom limbs – the feeling of the physical presence of a limb after it has been damaged or removed – and gives a wonderful insight how the brain perceives non-functioning or non-existent body parts.

In fact, most people who have a limb amputated will experience a phantom limb, although they often fade over time.

However, the feeling is usually not an exact representation of how the actual limb felt before it was removed, but can involve curious and sometimes painful ‘distortions’ in its perceived physical size, shape or location.

The Brain article looks at the diversity of phantom limb ‘shapes’ through their visual depictions.

The image on the left is from a 1952 case report where an amputation involved a ‘Krukenberg procedure‘.

This operation is rarely performed in the modern world but it involves the surgeon splitting the stump to allow pincer movements – and in this case it left the patient with the feeling of divided phantom hand.

In other cases, without any out-of-the-ordinary surgical procedure, patients can be left with a phantom that feels like the middle parts of their limb are missing while they still experience sensations in phantom extremities.

The drawing on the right was completed by a patient in a medical case study to illustrate their experience of a post-arm-amputation phantom limb.

In this case, the person experienced the feeling of a phantom hand on their shoulder stump, but had no experience of an intervening phantom arm.

While phantom limbs are usually associated with amputations, the phenomenon is actually caused by the mismatch between the lack of sensory input from the limb and the fact that the brain’s somatosensory map of the body is still intact and trying to generation sensations.

This means that any sensory disconnection, perhaps through nerve or spinal damage, can cause the experience of a phantom limb, even if the actual limbs are still there.

In the drawing on the left, a patient who suffered spinal damage that caused a loss of sensation in their limbs, illustrated how their phantom legs felt.

Although their own legs were completely ‘numb’ the phantom legs felt like they were bent at the knee, regardless of where their actual legs were positioned.

Normally, feedback from real world actions and sensations keeps the somatosensory map tied to the genuine size and shape of the body, but these sensations can begin to generate distorted sensations when this connection is broken through damage.

However, the stability of our experience of body size, shape and position is remarkably flexible in everyone as the rubber hand illusion shows.

Link to locked Brain article on depictions of phantom limbs.