Category: Hypnosis

LSD boosts people’s suggestibility, raising possibility of clinical uses

A rigorously controlled new study reports that a dose of LSD makes us more susceptible to suggestions, a finding that raises the possibility of clinical usage in contexts where hypnosis has proven effective.

The study recruited 10 participants (9 men), aged 27–47, all of whom had used psychedelics in the past, but were clear of any diagnosis of mental illness. They attended two testing sessions 5–10 days apart where placebo was administered in the first session, and a standard dose of LSD (40–80 μg) on the second. This fixed order was necessary to avoid any leakage of psychedelic effects from one session to another, mimicking the design of an earlier experiment on nitrous oxide.

Two hours after receiving placebo/dose, participants closed their eyes and were led through a series of standard suggestions used in hypnosis research, such as imagining hearing exquisite music, feeling time slowing, or their finger becoming numb. Their subsequent ratings of vividness of the imaginings were nearly one point higher (on a five-point scale) in the LSD session than the placebo, a significant effect.

LSD led to bigger rises in suggestibility for participants who scored higher on a measure of conscientiousness. Conscientiousness is associated with “ego control”, and it may be that LSD’s much-reported effect of “ego dissolution” may be pulling down bulwarks that would otherwise make these individuals resistant to accepting suggestions.

If you’ve had personal experience with LSD, the results of this study may seem plausible to you. If you haven’t, users report a sense of the external world mingling with their own thoughts. Also, groups of people who “go on a trip” together tend to converge on the same ideas and feelings in an uncanny fashion. Given these subjective accounts it makes sense that the drug was associated with increased suggestibility in this research. The practical significance of this finding is that it shows the malleability offered by LSD has parallels with how hypnosis operates, justifying and paving the way for exploration of LSD in contexts where hypnosis has proven effective – clinically in areas such as pain, PTSD and weight loss, often in conjunction with other interventions.

It’s high time for LSD to receive this renewed focus. Its potential for suggestibility was investigated clinically – albeit without the placebo controls we see here – way back in the 1950s (and no doubt influenced its investigation in the CIA’s infamous MK-Ultra programme for mind control). Indeed, in its early days LSD was considered full of promise for clinical applications; a meta-analysis of a set of trials looking at LSD treatment for alcoholism showed an effect that hasn’t been bettered by any other means.

Regulatory restrictions imposed in the mid–1960s slammed shut the door onto these perceptions, forcing later researchers to operate in an unwelcoming climate, including political obstacles and costly, difficult licensing criteria, which explains why peer-reviewed articles gave way to albums and other missives of the counterculture as our main sources of information about the significance of hallucinogens.

Now we may be seeing the beginning of a renaissance of psychedelic research, with fuller understanding of its activity at the levels of neuronal populations and brain regions, and clinical investigation into its use to reduce anxiety in those with terminal illness. If you are interested in these issues, and more, be sure to check out the September issue of the Psychologist, which focuses on hallucinogens. It’s entirely open access and free to everyone. _________________________________

  ResearchBlogging.orgR. L. Carhart-Harris & M. Kaelen & M. G. Whalley & 7 M. Bolstridge & A. Feilding & D. J. Nutt. (2014). LSD enhances suggestibility in healthy volunteers. Psychopharmacology.

Post written by Alex Fradera (@alexfradera) for the BPS Research Digest.

Neuroscience gets serious about hypnosis

Hypnosis is synonymous with stage entertainment where the performer puts volunteers from the audience into a trance and commands them to do embarrassing things. This makes it sound like a joke, but in fact hypnosis is a real phenomenon and it is proving increasingly useful to psychologists and neuroscientists, granting new insights into mental processes and medically unexplained neurological disorders.

That’s according to David Oakley and Peter Halligan who have written an authoritative new review, debunking hypnosis myths, and covering ways that neuroscience is shedding light on hypnosis and ways hypnosis is aiding neuroscience.

Despite popular folklore, hypnosis is not a form of sleep (this misconception isn’t helped by the fact that hypnosis studies typically label the control condition the “waking state”). However, Oakley and Halligan say new brain imaging findings do support the contention that hypnosis is a distinct form of consciousness. After successful hypnotic induction, which involves using mental strategies to reach “a focused and absorbed attentional state”, participants show reduced activity in parts of the brain’s default mode network together with increased activity in prefrontal attentional systems. Oakley and Halligan concede that “it remains to be seen if these particular changes are unique to hypnosis.”

After hypnotic induction (or in some cases even without it) participants exposed to suggestive statements can experience altered perceptual or bodily sensations. For instance, told that their arm is getting heavier and they cannot move it, a suggestible participant may experience paralysis of the arm. Sceptics may wonder about the veracity of these experiences but brain imaging results are indicating they are real and not merely imagined.

Consider a study of participants hypnotised and induced to see colourful Mondrian images in grey. Brain scan results of these participants showed altered activity in fusiform regions involved in colour processing, and crucially such changes weren’t observed when the participants merely imagined the Mondrians in grey. Another study showed that the famous Stroop effect disappeared when hypnotised participants received the suggestion that they would see words as meaningless symbols.

Another line of research explores the correlates of hypnotic suggestibility. Apparently it is a highly stable trait and it is heritable. It doesn’t correlate with the main personality dimensions but does correlate with creativity, empathy, mental absorption, fantasy proneness and people’s expectation that they will be prone to hypnotic procedures.

Many neurological symptoms are medically unexplained with no apparent organic cause and it is here that hypnosis is proving especially useful as a new way to model, explore and treat people’s symptoms. For instance people can be hypnotised to experience limb paralysis in a way that appears similar to the paralysis observed in conversion disorder. People can also be hypnotically induced to experience the sense that there is a stranger looking back at them when they peer in a mirror – an apparent analogue of the real “mirrored-self-misidentification delusion”. Hypnosis research is also exposing the apparent volitional element to mental phenomena previously considered automatic. For example, a patient who experienced face-colour synaesthesia received post-hypnotic suggestion that abolished the colours she usually sees with faces (as confirmed by a colour-naming task in which faces no longer had an interfering effect).

“The psychological disposition to modify and generate experiences following targeted suggestion remains one of the most remarkable but under-researched human cognitive abilities given its striking causal influence on behaviour and consciousness,” said Oakley and Halligan.

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Oakley DA, and Halligan PW (2013). Hypnotic suggestion: opportunities for cognitive neuroscience. Nature Reviews Neuroscience, 14 (8), 565-76 PMID: 23860312

–Further reading–
The hypnotised brain.
The efficacy of ‘hypnotic’ inductions depends on the label ‘hypnosis’.
Also: the latest Neurpod podcast covered this review paper.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

The hypnotised brain

Forget swinging pocket watches and unedifying stage antics, hypnosis is a genuinely useful tool for studying psychogenic symptoms – that is, neurological symptoms with no identifiable organic cause (known in psychiatry as “conversion disorder“, the idea being that emotional problems are “converted” into physical ailments).

Consider hand paralysis, which some patients complain of in the absence of any neurological injury or disease. In a new study led by Martin Pyka at the University of Marburg, hand paralysis was induced in 19 healthy participants through hypnosis, thus providing a model of what may be going on in conversion hand paralysis. The hypnotised participants had their brains scanned while they rested calmly, and these results were then compared against a second scanning session in which the participants were not hypnotised.

The main result is that hypnosis-induced hand paralysis was associated not with brain areas involved with inhibiting movement (e.g. the supplementary motor area, located towards the front of the brain), but with increased coupling between regions associated with representation of the self (especially the precuneus, located in the parietal lobe, and the posterior cingulate cortex), and with regions that represent and monitor one’s own movements (the dorsolateral prefrontal cortex). This suggests it’s not so much that the participants’ hand control was suppressed, but that they no longer believed they had the power to move their hands. This fits the findings from an earlier brain imaging study of a woman with conversion paralysis, which found changes in brain areas associated with self-monitoring and auto-biographical memory, but not areas associated with motor inhibition.

“We believe that the suggestions given during induction of hypnosis, which started with metaphors such as ‘the left hand feels weak, heavy, adynamic,’ ‘any energy leaves the hand,’ and continued with direct instructions like ‘the left hand is paralysed, you cannot move the hand anymore,’ induced an altered self-perception of the participants and their motor abilities,” the researchers said. They acknowledged that a weakness of their study was that they’d deliberately recruited highly suggestible participants: “Thus, it is unclear whether the reported functional coupling can only be attributed to the neurofunctional impact of hypnosis or also to the selection of the subjects,” they said.

As an aside, Jean-Martin Charcot, the “Napoleon of neurology”, considered hyponosis-proneness to be a hallmark of patients with hysteria – a now defunct catch-all diagnosis, which included patients with conversion disorder. At the end of the 19th century at the Salpêtrière Hospital in Paris, Charcot often hypnotised his hysterical patients during his series of hugely popular public demonstrations of the condition. Hypnosis also became a common means of treatment for hysteria (although Charcot himself was not an advocate), whereby the entranced patient revealed, often via new emerging “personalities”, the past traumas and fixed ideas at the root of their physical ailments. Hypnosis as a treatment fell out of favour with Freud’s rise to prominence: he believed it was possible to get to the root of a patient’s subconscious problems by talking to them directly, without the need for hypnosis.
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ResearchBlogging.orgPyka, M., Burgmer, M., Lenzen, T., Pioch, R., Dannlowski, U., Pfleiderer, B., Ewert, A., Heuft, G., Arolt, V., and Konrad, C. (2011). Brain correlates of hypnotic paralysis—a resting-state fMRI study. NeuroImage, 56 (4), 2173-2182 DOI: 10.1016/j.neuroimage.2011.03.078

This post was written by Christian Jarrett for the BPS Research Digest.