N,N dimethyltryptamine (DMT) is a powerful psychotropic drug. It occurs in its pure state as a white or yellowish-red crystalline form. It is obtained from plants found in Mexico, South America and Asia. It is commonly inhaled, causing reactions that last from 5 to 45 minutes. But when mixed in an infusion, such as the South American drink ayahuasca, reactions can last three to four hours.
DMT can produce visual and auditory hallucinations, as well as euphoria, dilated pupils, increased heart rate and blood pressure, dizziness, coordination problems, nausea, anxiety and paranoia. High doses can lead to coma and serotonin syndrome, the symptoms of which are agitation, muscle rigidity, migraine, chills, diarrhoea and fever. This can also lead to seizures, irregular heartbeat, unconsciousness and death.
In the last few years, psychedelic serotonergic drugs have again attracted the attention of neuroscientists. While drugs such as psilocybin, LSD and DMT are not new and have been studied extensively over the years (since the 1950s), the modern interest in them stems from the availability of new investigative technologies since those years.
The most significant and reliable correlate of the psychedelic experience is a reduction in spontaneous oscillatory activity (especially in the alpha range) and an increase in signal diversity and complexity, measured by electroencephalography or magnetoencephalography.
As far as neuroimaging is concerned, alterations in connectivity between distinct functional networks will appear in a functional MRI. This alteration would be attributable to the activation of neurons in the pyramidal layer, which are rich in 5HT2A serotonin receptors.
However, the studies conducted so far (several publications by the Carhart-Harris group) are characterised by the rigidly controlled, artificial hospital environment, which tends to eliminate the non-pharmacological variables of the experiment and which therefore tends to make the results difficult to extend outside the laboratory. The psychedelic experience is in fact strongly determined not only by the subject's mental state ('set') but also by the environment ('setting').
In fact, a 2018 study by Haijen demonstrated this "bias", observing that subjects who were well disposed towards the experiment, comfortable in the hospital environment and highly motivated, had more mystical and euphoric experiences ("peak experiences") and, in general, subjects reported an increased well-being.
The reality is that users of psychedelic substances gather in environments quite different from hospitals: quiet areas, with a considered choice of music, perfumes and colours. The experiences are desired and sought after, and therefore the mental 'set' is positive and favours pleasant experiences.
Therefore, Pallavicini's group designed a study aimed at assessing the psychedelic effects of DMT in a natural environmental setting, desired by the participants, with minimization of the "artificiality" of monitoring by means of a wireless EEG. The results of the study were presented during the Insight 2021 congress by Federico Zamberlan, from the Physics Department of the University of Buenos Aires.
In the experiment, before and after consumption (using inhaled 'free base' DMT), the 35 participants completed a series of questionnaires designed to investigate the content and psychological characteristics of their experience, any near-death experiences, and their state of anxiety.
From an electrophysiological point of view, the results show that DMT significantly reduces the intensity ("power") of the alpha (8-12) oscillations at all measurement sites, while the delta (1-4 Hz) and gamma (30-40 Hz) oscillations are increased. An important result noted is that the increase in gamma waves correlates with a reported state of mystical experience, detected by the test batteries used. A study of this kind therefore allows for a better investigation of the experiences of psychedelic substance use than the clinic setting, which should be taken into consideration for future studies.