David Nichols, PhD, a leading expert in the field of psychedelic research and the founding president of the Heffter Research Institute, often answers the question, “What is a psychedelic?” by saying, “The scientific definition I always use is that they are substances that produce changes in thought, mood, and affect, which only occur during dreaming or religious exaltation.”1,2 However, this definition does not account for the experiences of naturally occurring psychoses, such as those seen in schizophrenia.
The phenomenology of psychotic experiences between drug-induced and naturally occurring psychoses differs, and the use of psychedelics does not necessarily replicate or simulate the symptoms of schizophrenia. For example, drug induced hallucinations are often described as more intense and vivid, while those associated with schizophrenia are described as more persistent and distressing.3
An altered state of consciousness is a hallmark of a psychedelic trip, but not a characteristic of schizophrenia. Patients with schizophrenia who have used psychedelics typically report that their experiences under the influence of these drugs are distinct from their usual experiences with the condition. Additionally, according to many experts, the underlying neurobiological mechanisms are different, with psychedelics affecting serotonin receptors and schizophrenia thought to be linked more to dopamine dysregulation, among other factors.
However, there are some instances of naturally occurring psychoses that are difficult to distinguish from the experiences reported by those who take psychedelics. This article explores the similarities between psychedelic experiences induced by serotonergic psychedelics, 5-HT2A agonists, such as LSD, psilocybin, and mescaline, and a rare psychiatric disorder known as the “oneiroid state.”
Origins and definitions
The term “oneiroia” is derived from the Greek words for “sleep” and “similar,” referring to the dreamlike character of the condition. It is widely acknowledged that psychedelics can temporarily induce dreamlike states,4 but this article focuses specifically on the naturally occurring, endogenous dreamlike state.
Oneiroid state was first described by German psychiatrist Wilhelm Mayer-Gross in the early 20th century and was once well-known among European psychiatrists. Some classified it as a part of schizophrenia, others saw it as an unusual manifestation of affective disorder, and still others considered it an atypical psychosis. Nevertheless, this phenomenon has received limited attention in American psychiatric journals.
The key characteristic of this condition is a distinctive state of consciousness marked by vivid and florid hallucinations, and a succession of constantly shifting dreamlike or surrealistic visuals and imagery often similar to mystical or cosmic experiences. Self-awareness and orientation in time and place are often disturbed, and delusions are experienced within this altered state.5
To gain a better understanding of the oneiroid state, it may be helpful to turn to European or other schools of psychiatry with a history of studying this phenomenon, as American psychiatry has limited knowledge in this area.
As described in the “Handbook of Psychiatry” by Russian psychiatrist A.V. Snezhnevsky, published in 1983, oneiroid state, also known as oneiroid syndrome, is a dreamlike and imaginative state characterized by a bizarre combination of reality and vivid phantasmagoric imaginations.6 In this state, individuals are completely detached from their surroundings and experience a change in self-awareness, often displaying either a lack of movement or senseless excitement.
Patients often experience the oneiroid state as active participants, as if they are in a movie theater, not only watching the story, but also being part of it, reacting to it with either “external immobility” or senseless excitement, completely detached from their surroundings. This is similar to the portrayal of the emotions of the characters in Steven Spielberg’s film “Ready Player One.”
The entry in Dr. Snezhnevsky’s “Handbook” states: “Some patients in Oneiroid State experience travels to other worlds, such as interacting with inhabitants on Mars, collecting gems on the moon, exploring invisible cities, participating in conspiracies and insurrections, fighting with pirates, chasing The Flying Dutchman, wandering through ancient Rome, and even visiting heaven or hell. At times, the patient’s imagination reaches a state of mystical contemplation.”6
In contrast to delirium, which never impairs self-awareness, oneiroid state is marked by drastic changes in the sense of self. The memory of the subjective experience during the oneiroia is much more vivid and consistent than in delirium. Patients who have experienced the oneiroid state often have complete recall of their experience, as if they have just woken up from a dream.
It was commonly thought that oneiroid state was part of the group of functional psychoses, rather than organic psychoses, and was not considered to be a result of mind-altering psychedelics. It was not considered a manifestation of epilepsy either. Oneiroid state could last for weeks or even months, making it unlikely to be related to an epileptic seizure. Furthermore, EEG results did not show any seizurelike activity during the state.
An excellent case study on oneiroid state was published in Israel in 2000. The authors described two patients who experienced the oneiroid state for several days or even weeks.7 One of the patients reported that during the illness, he experienced himself aboard a spaceship as a cosmonaut, heading for a different universe. On another occasion, the patient perceived himself as a person living 2,000 years ago and being guilty of Christ’s death.
The second patient reported that everything around her appeared “like in the movies,” and she saw others as characters from comic strips. Both patients alternated between catatonic excitement and sluggishness and would sometimes come back to reality for a few minutes to respond to questions. Physical exams, laboratory tests, neurological tests, and a brain scan were all normal in both cases.