features intense anxiety, confusion, and agitation, or even psychotic episodes. Bad trips can be connected to the anxious ego-dissolution (AED) dimension of the APZ questionnaire used in research on psychedelic experiences. As of 2011, exact data on the frequency of bad trips are not available. Some research suggests that the risk of a bad trip on psilocybin is higher when multiple drugs are used, when the user has a history of certain mental illnesses, and when the user is not supervised by a sober person. In clinical research settings, precautions including the screening and preparation of participants, the training of the session monitors who will be present during the experience, and the selection of appropriate physical setting can minimize the likelihood of psychological distress. Researchers have suggested that the presence of professional "trip sitters" (i.e., session monitors) may significantly reduce the negative experiences associated with a bad trip. In most cases in which anxiety arises during a supervised psychedelic experience, reassurance from the session monitor is adequate to resolve it; however, if distress becomes intense it can be treated pharmacologically, for example with the benzodiazepine diazepam. The psychiatrist Stanislav Grof wrote that unpleasant psychedelic experiences are not necessarily unhealthy or undesirable, arguing that they may have potential for psychological healing and lead to breakthrough and resolution of unresolved psychic issues. Drawing on narrative theory, the authors of a 2021 study of 50 users of psychedelics found that many described bad trips as having been sources of insight or even turning points in life. Scientific models Link R. Swanson divides scientific frameworks for understanding psychedelic experiences into two waves. In the first wave, encompassing nineteenth- and twentieth-century frameworks, he includes model psychosis theory (the psychotomimetic paradigm), filtration theory, and psychoanalytic theory. In the second wave of theories, encompassing twenty-first-century frameworks, Swanson includes entropic brain theory, integrated information theory, and predictive processing. Model psychosis theory Researchers studying mescaline in the early twentieth century and LSD in the mid-twentieth century took interest in these drugs as producing a temporary "model psychosis" that could assist researchers and medical students in understanding the experiences of patients with schizophrenia and other psychotic disorders. Filtration theory Aldous Huxley and Humphrey Osmond applied the pre-existing ideas of filtration theory, which held that the brain filters what enters into consciousness, to explain psychedelic experiences (and it is from this paradigm that the term psychedelic is derived). Huxley believed that