Altered states of consciousness

The philosophy of psychedelic transformation  ::  Chris Letheby  ::

Summary and review of the above article

INTRODUCTION:   It is argued that altered states, which can result from a range of cause including near-death-experience (NDE), meditation or psychedelic drugs, can be directly causal of durable personality changes. Further to this, recent experimentation suggests that some altered states can deactivate brain regions responsible both for the sense of self, and for constraining ‘mystical’ type experiences in other brain regions. Thus contrary to any suggestion that the self is some type of ‘mystical illusion’ it may in fact be part of a system that constrains ‘mystical’ experience during normal brain processing. 

This discussion of altered states relates to the potential for using psychedelic drugs as medical therapies, following on a revival of scientific research in this area. It is pointed out that psychedelic interventions involve conscious mental representation, in contrast to normal drugs, where the process of interaction is outside of consciousness. nrn2884-i2The debate here is as to whether the effects of these drugs derive from the mental representations or altered states of consciousness (ASC) associated with them, or from the unconscious interaction of the drug molecules; this would put them in essentially the same category as other medical drugs.

The term hallucinogen, i.e. giving rise to hallucinations can give a sloppy impression that the mental representations cannot be of any importance. In more scientific terms, however, hallucination means a representation that is not directly triggered by external stimuli, but this definition say nothing about the representation’s capacity for influencing other brain regions or behaviour.

Altered states

Psychedelic drugs are quite diverse in both their molecular structure and in the receptors they bind to, but have a common quality of giving rise to altered state of consciousness. All the drugs are seen to alter at least some of a group of experiences, including sensory experience, emotional experience, spatial and temporal experience, bodily experience, sense of self and reasoning. Such alterations vary in intensity. Representations can arise that have no direct basis in external stimuli, but at the same time, external stimuli can be distorted, intensified or diminished. Plant-based psychedelics, such as psilocybin, mescaline and DMT have long been used in the rituals of traditional cultures.

Research in recent years looks to support the argument that the mental representations involved in altered states are at least in part responsible for subsequent life changes in subjects. The contrary argument that only the unconscious interaction at receptors has influence has a look of the perversity, so often found in consciousness studies and related areas, based on a fear of anything that could be classed as ‘supernatural’, plus on an unacknowledged ‘closet Cartesian’ believe in what is conscious having nothing physical to do with what is body or even brain.DialoguesClinNeurosci-3-265-g004


Psilocybin has been the psychedelic most involved in modern research. Small scale studies have suggested that the drug has beneficial effects for obsessive compulsive disorder, depression and addictions. One experiment with psilocybin involved 36 mentally normal subjects, with no previous psychedelic experience but experience of religious/spiritual activities; out of 36 subjects, 22 had a ‘complete mystical experience’, as measured by a standard questionnaire, and involving internal and external unity, transcendence of time and space, sense of sacredness, positive mood and ineffability. Those subjects who had such an experience also showed an increase in openness of personality. This change was diminished, but still significant, at a 14 month follow-up check. This is viewed as being remarkable because very few drug interventions result in such durable personality changes.

Contrary argument

The prima facie case appears to be that the altered state produces the change in personality. In the normal course of waking life there is nothing unusual or mystic in a meaningful experience having an impact on subsequent attitudes or behaviour. 4 levels, no textHowever, the contrary argument is that while subjects may think they have had a transformative experience with meaning for them, they are mistaken and only the unconscious action of the drug is relevant. This argument might have a problem with NDE, which is also personality transforming, but is unrelated to drugs related to mood or mental well being. Further to this, psychedelic drugs can be effective at a single dose, as in the experiment with psilocybin described above, which is not the norm with mental-orientated drug therapies.

Four lines of evidence

The author argues that there are at least four lines of evidence supporting the case that changes in the mental experience lead to long-term therapeutic benefits. Some altered states that do not involve drugs are also seen to produce long-term benefits. Meditative practise and non-drug induced ‘mystical’ experiences such as near-death-experiences (NDE) are seen to have psychological or personality effects. Although it is difficult, or more often impossible to study these under controlled conditions, the similarity of experience to those induced by psychedelics  strongly suggests that the same causal relations apply.

There is evidence for some direct similarities between psychedelics and meditation, with deactivation of the posterior cingulate reported for both conditions. This relates to a loss of sense of self in both cases. Other experiences are also reported from both psychedelics and Buddhist meditation.

Psychedelics & meditation

A fall-back argument is that the mental representation and the molecular interaction are one and the same thing at different levels, at least in the psychedelic cases, but even this is not properly supported by research. In the cases of psilocybin, the molecules bind to serotonin receptors in pyramidal neurons in layer 5 of the cortex, but there is a knock-on effect from the layer 5 neurons to subcortical regions, where the drug does not bind to receptors. Further evidence shows a correlation between between variables used to quantify altered states such as those induced by psilocybin, and those used to quantify increased openness of personality.


In another small double-blind experiment, there was a comparison between the psychedelic drug, ketamine, in both high and low doses, and the non-psychedelic anxiety-reduction drug, lorazepam. The higher dose of ketamine led to a greater reported tendency to reduce addiction, and was associated with a correlated variation of experiences under the drug.

Default-mode-network & the self

In a well-known recent experiment at Imperial College, psilocybin produced a decrease rather than the anticipated increase in neural activity. 531571297_640The decrease in activity was particularly marked in the default-mode-network (DMN), responsible for much of the brain’s resting state. Despite its association with resting, this network is normally more active than the rest of the brain, and has a high level of connections with other brain regions. Some researchers hypothesise that the default network creates the sense of self, and in that case deactivation of the network would explain the loss of the self sometimes associated with altered states.

Posterior cingulate

The posterior cingulate whose deactivation is related to altered states forms part of the default-mode-network. Psilocybin additionally disrupts connections between the default network and other brain regions. The suggestion here is that disruption of the default-mode-network removes inhibitions or constraints from other areas of the brain. The potential for the self to be dissolved in altered states, as a result of deactivation in the posterior cingulate or other brain regions, argues against the popular notion that experience could not happen without a sense of self.

Conclusion:   Contrary to any idea that the self is some kind of ‘mystic illusion’, it might now appear that it is part of a system that normally constrains the types of altered states of consciousness that are classed as ‘mystic’.

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