Zolpidem is a prescription sedative used for short-term treatment of clinical insomnia; it is commonly known by its brand name ‘Ambien’. Zolpidem is to be taken at bedtime with the intended effect of aiding individuals in falling asleep. While ‘Ambien CR’ is a variation on the original drug with a second slow release layer intended to keep individuals asleep, ‘Ambien’ does not aid in maintaining sleep; rather, it has possible side effects of parasomnias such as somnambulism (sleep walking), sleep eating, sleep sex, sleep driving, and other such complex behaviours normally attributed to the realm of the conscious.
In one of many similar cases, a woman was prescribed the non-extended release zolpidem for insomnia and upon falling into zolpidem induced sleep, she would wake up an hour or two later and speak in short incoherent phrases and walk into her kitchen to eat “a loaf of bread, cold cereal, or leftover food. The following morning she would have abdominal fullness, find her kitchen messy, and have complete amnesia for the event. The patient would also leave her home and walk on her front porch or on her front lawn.” (Hoque et al). On one occasion, she “drove her automobile 10 miles from her home and was found asleep behind the wheel by police. She had a vague recollection of this event, but thought that she was dreaming.” (Hoque et al). Once she ceased taking zolpidem, the parasomnia also ceased.
Cases of zolpidem induced parasomnia typically report that patients have no recollection of their activities during the night and “patients who do not recall waking events on zolpidem are typically cognitively functional, and retain the ability to speak in coherent short phrases” (Hoque et al). These patients have been roused from sleep into wakefulness - their cognitive abilities are testament to their undoubted wakefulness - yet, one might find it difficult to attribute ‘consciousness’ to these episodes of parasomnia, as their truly awake conscious selves have no recollection of their behaviour or the night’s events. “A possible explanation for zolpidem-induced nocturnal events is that after an arousal from sleep into wakefulness, nocturnal activity (i.e., walking, eating, or driving) occurred and was subsequently not recalled after returning to sleep because of the sedation-mediated amnestic properties of zolpidem” (Hoque et al). The lack of recollection itself should not count against consciousness, but the disordered processing of the external world when under parasomnia should indicate a level of awareness below that of full consciousness.
This state in which parasomnia patients find themselves in falls somewhere in-between truly asleep and truly awake; this would indicate there exists a spectrum of consciousness, and these patients are slipping into this usually unexplored in-between under the influence of zolpidem. These patients are conscious and take zolpidem for its intended effect of easing them into unconsciousness; that is, zolpidem shifts their state of consciousness from conscious towards unconscious.
Zolpidem has also been shown to be effective in shifting states of consciousness from unconscious toward conscious. In patients with disorders of consciousness, there are three ascending levels of consciousness: coma, vegetative state (VS), and minimally conscious state (MCS) (Whyte et al). Patients in a state of coma are unresponsive with eyed closed and it is debated whether they are aware of external stimuli. Patients in a vegetative state are unresponsive but ‘awake’ with their eyes open. Patients in a minimally conscious state can be lower functioning, demonstrating only visual pursuit, or be higher functioning with additional signs of consciousness such as command following and motor localization (Whyte et al). Emergence from the minimally conscious state into a state of higher consciousness is indicated by functional object use or reliable communication (Whyte et al).
Zolpidem has been shown, through clinical trials, to be effective in inducing a temporary consciousness and improving cognition and motor function in vegetative and minimally conscious individuals. The first discovery of this phenomenon was in a patient named Louis Viljoen from South Africa in 1999. Louis was cycling home after work when he was hit by a truck, suffering brain damage that left him in a persistent vegetative state for the next three years. One day, his mother fed him a ground up a zolpidem tablet through a straw to treat his involuntary muscle spasms; 20 minutes later, Louis spoke for the first time in three years: “Hello mummy”, and was able to control his limbs and facial muscles (Morris). His primary doctor confirmed this occurrence and replicated the phenomenon.
This phenomenon was formally studied in a double blind placebo controlled experiment by Dr. John Whyte and his team; their aim was to discover whether there exists any demographic or neurophysiological predictors for a positive response to zolpidem (Whyte et al). They looked at cases of both traumatic and non-traumatic brain injury in patients who were either in a vegetative or minimally conscious state for a minimum of 4 months and had not received zolpidem with the intention of improving consciousness.
The experiment was conducted over three phases. In the first phase, 84 participants were enrolled to receive zolpidem on a designated study day and a placebo on another designated study day. Neither the participant’s caregiver nor the doctor had knowledge of whether it was a drug or placebo that was on administered on a particular day. On both study days, the participant’s primary caregiver monitored the patient during the three hour window of the drug’s effectiveness, making note of any novel behaviours, and reporting whether the participant seemed better than usual in a variety of behaviours, such as visual pursuit, command following, verbalization, and other indicators of alertness (Whyte et al). Participants were labelled as “probable responders” if their caregiver observed improvements to their level of consciousness on the day that zolpidem was administered and not on the day that the placebo was given. Out of the 84 initial participants, 28 were marked as “probable responders. In the second phase, a research assistant attempted to replicate the results using the same double-blind placebo-controlled methodology as the first phase, with the addition of quantifying the participant’s changes in consciousness on the Coma Recovery Scale - Revised (CSR-R). The participant was designated a “definite responder” if again, an improvement to their level of consciousness corresponded to the day of zolpidem administration. From the 28 “probable responders”, four participants continued to the third phase as “definite responders”. In the third phase, the “definite responders” and a subset of non-responders underwent structural and functional neuroimaging and EEP and ERP. Unfortunately, no biomarkers or demographic differences or differences in injury were found that might differentiate zolpidem responders from non-responders (Whyte et al).
Although differentiating factors were limited, many similarities in response were noted. All zolpidem responders regained consciousness within an hour of receiving the drug, experienced increased responsiveness and social interaction, demonstrated increased environmental interaction, and recovered several meaningful behavioural milestones such as communication, intelligible speech, functional object use, command following, and object recognition (Whyte et al). Consistent with the drug’s pharmacokinetics, the responders returned to their prior states of unconsciousness after 4 hours (Whyte et al). The effect of zolpidem on their consciousness did not wane with repeated dosing.
From these experiments, it’s shown that Zolpidem, intended to be a sedative shifting its users from consciousness to unconsciousness, can also increase arousal from unconsciousness towards consciousness. This effect is known as “paradoxical arousal” (Schiff), because the opposite of the intended effect occurs. Yet, instead of viewing these effects as a paradox - shifting individuals from one end of the spectrum of consciousness to the other in both directions, perhaps it helps to unify them and consider the effect of zolpidem as shifting consciousness inwards, towards the center of the spectrum, rather than outwards to either ends.
The analogous philosophical construct of an individual falling into disputed consciousness is the philosophical zombie (p-zombie). The p-zombie is commonly used as a thought experiment highlighting the “hard problem” (Chalmers) of consciousness: a p-zombie has all the functions of a human - looks like a human, acts like a human, has all the same brain structures and processes as a human, interacts with the outside world in the same way as a human - except it lacks consciousness, By definition, the p-zombie lacks conscious phenomenon such as qualia - yet, what does it mean to be unconscious while enjoying all the functions of a conscious being? For a p-zombie to have the “complex information processing required to provide for it a salience landscape with dynamically nested orders of relevance and significance” (Vervaeke et al), it would be difficult to consider the p-zombie as entirely unconscious - the p-zombie would need to be capable of relevance realization and would need to “care about objects and events” (Vervaeke et al). Although qualia is missing by definition from the p-zombie, it is also not clear that the zombie is not conscious. This would leave the p-zombie somewhere in-between not conscious and not not conscious.
Considering the p-zombie then on a spectrum of consciousness, it would not be too far from the case of a person experiencing an episode of parasomnia. The case of the p-zombie is sometimes dismissed on the basis of its plausibility or lack thereof. The p-zombie is meant to be a significant problem for cognitive science; it has all the functions of consciousness that are part of the “soft problems” of consciousness. The “hard problem” of consciousness, as proposed by Chalmers concerns “the problem of experience” which “is hard precisely because it is not a problem about the performance of functions” (Chalmers). We have subjective experiences such as the redness of red, that make up phenomenal consciousness. The issue with this “hard problem” of consciousness is that it assumes that conscious experience is necessary for consciousness.
For the nature of consciousness, the “hard problem” is used to illustrate a deficiency in physicalist accounts of consciousness, since conscious experience is not a physical function; the redness of red escapes empirical examination. Yet, in examining the cases of zolpidem reaction, it can be shown that an empirical account of qualia is in no way the determining factor for a plausible account of consciousness.
Consider the opposite of a p-zombie - let it be called a v-zombie, a philosophical analogue to VS/MCS individuals: the v-zombie experiences phenomenal consciousness - sees the redness of red - yet lacks the cognitive functions typically attributed to conscious individuals, the “easy problems” of consciousness, such as “the deliberate control of behaviour”, “the focus of attention”, or the “ability to discriminate, categorize, and react to environmental stimuli” (Chalmers). V-zombies ought not to be considered truly conscious merely from their experience of qualia. There needs to be no philosophical argument on the conceivability of p-zombies or v-zombies when their plausibility lives in individuals experiencing altered states of consciousness under zolpidem.
The Scale-Invariant Mutual Modelling theory of consciousness gives a thought experiment concerning a ‘turbocharged’ zombie, which is a p-zombie containing all the aforementioned complex information processing that would be required in order to truly have the functions of a conscious human. From the turbocharged p-zombie, it is concluded that “the loss of qualia does not necessarily entail the loss of consciousness” (Vervaeke et al). Furthermore, from the cases of zolpidem induced parasomnia and VS/MCS, whether or not sleepwalkers or VS/MCS experience qualia is a question that seems to have no bearing on their level of consciousness. It is not qualia itself that determines one’s level of consciousness. All that qualia can indicate is that an individual is not fully unconscious; qualia indicates nothing about where along the spectrum of consciousness an individual may be. If the loss of qualia does not necessarily entail the loss of consciousness and the presence of qualia does not necessarily entail the presence of full consciousness, then “attributions of consciousness do not seem to depend on the presence of qualia” (Vervaeke et al).
While it is not clear that a turbocharged zombie is not conscious, it is more clear that a v-zombie is not quite conscious; therefore, on a spectrum of consciousness, the turbocharged zombie would be attributed a higher level of consciousness than the v-zombie. Since the qualities of the turbocharged zombie are implicit in a p-zombie based on the premise that the p-zombie has all the capabilities of a conscious being, it then follows that the p-zombie has a higher level of consciousness than the v-zombie. If a higher level of consciousness can be attributed to a p-zombie with no experience of qualia than to a v-zombie with only conscious experience that it is unable to cognitively process, then it is not clear that conscious experience such as qualia ought to be considered as so crucial a requirement of theories of consciousness.
According to with Tononi’s Information Integration Theory, consciousness is no more and no less than just information integration: “consciousness corresponds to the capacity of a system to integrate information”. For Tononi’s theory to be plausible, zolpidem must work in some capacity by increasing the capacity of a patient’s thalamocortical system to integrate information. Tononi proposes the thought experiment: “you could be in a coma for days, awaken to consciousness for just one second, and revert to a coma. As long as your thalamocortical system can function well for that second, you will be conscious. That is, a system does not have to explore its repertoire of states to be conscious, or to know how conscious it is supposed to be: what counts is only that the repertoire is potentially available.” The case studies of zolpidem response in VS/MCS individuals confirm this thought experiment: the thalamocortical system of VS/MCS individuals function briefly under reaction to zolpidem and the individuals have an increased level of consciousness. This spectrum of consciousness fits well into information integration theory; Tononi notes that “consciousness is not an all-or-none property, but it is graded to varying degrees”.
There are phenomenological differences between individuals during a parasomnia episode and VS/MCS individuals under zolpidem response. While a parasomniac interacts with their external world to an extent, they are described as being largely unaware of other people. For the VS/MCS individual, their level of consciousness is determined largely by the level to which they are aware of and capable of interacting with the external world. For the functional role of consciousness, this emphasizes the role that consciousness plays in interaction with the external world. It is the functions of consciousness that are its symptoms.
According to Baars’ Global Workspace Theory, we have vast “unconscious sources of knowledge” and consciousness is the “gateway” through which we access it; consciousness is the point where input converges and output diverges. It is not clear how the Global Workspace Theory would accommodate levels of consciousness. As Vervaeke et al remarks in SIMM, “The philosophical zombie thus constitutes a possible counterexample to the GWT. Using Block’s distinction between “access consciousness” and “phenomenal consciousness”, one may well imagine a being that enjoys a fully functional global workspace architecture (and hence instantiates access consciousness) yet lacks phenomenal consciousness.” Both the parasomniac and the VS zolpidem responder lack key aspects of phenomenal consciousness, while both exhibits some behaviours that indicate a global workspace.
These bizarre effects of zolpidem have shown that there is a spectrum of consciousness and it is possible to induce conscious states along the spectrum. For cognitive science, theories of consciousness must then account for a consciousness that is fluid along a spectrum rather than the binaries of unconscious and conscious. On this spectrum, it can be shown by thought experiments of the p-zombie and v-zombie that possessing qualia does not indicate having a higher level of consciousness. The nature of consciousness plays a lesser role in determining consciousness than does the functions of consciousness.
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