Psychotic-Like Experiences and Their Cognitive Appraisal Under Short-Term Sensory Deprivation

Abstract

Aims: This study aimed to establish and compare the effects of brief sensory deprivation on individuals differing in trait hallucination proneness.Method: Eighteen participants selected for high hallucination proneness were compared against 18 participants rating low on this trait. The presence of psychotic-like experiences (PLEs), and participants’ cognitive appraisals of these, was evaluated in three different settings: at baseline, in a “secluded office” environment, and in light-and-sound sensory deprivation.Results: Psychotic-like experiences were experienced significantly more often in sensory deprivation for both groups. In particular, both experienced slight increases in perceptual distortions and anhedonia in seclusion, and these increased further during sensory deprivation. Highly hallucination prone individuals showed a significantly greater increase in perceptual distortions in sensory deprivation than did non-prone individuals suggesting a state-trait interaction. Their appraisals of these anomalous experiences were compared to both clinical and non-clinical individuals experiencing psychotic symptoms in everyday life.Conclusion: Short-term sensory deprivation is a potentially useful paradigm to model psychotic experiences, as it is a non-pharmacological tool for temporarily inducing psychotic-like states and is entirely safe at short duration. Experiences occur more frequently, though not exclusively, in those at putative risk of a psychotic disorder. The appraisals of anomalous experiences arising are largely consistent with previous observations of non-clinical individuals though importantly lacked the general positivity of the latter.

Predicting Psychotic-Like Experiences during Sensory Deprivation

“…This finding was highly marked and consistent with previous studies [14, 17]. However, unlike previous studies, no significant state/trait interactions were found on other PSI scales.…”

Inducing Psychotic-like Experiences without Drugs using the Witches’ Cradle

“…As predicted use of the cradle appeared to temporarily increase the likelihood of psychotic-like experiences, though perhaps to an attenuated extent when compared with other drug and non-drug (sensory deprivation) contexts in that the elevation of scores above baseline was more muted [7][8][9]. While the PSI score under experimental conditions was similar to those seen in sensory deprivation and when using cannabis recreationally, the baseline PSI score was somewhat elevated when compared to baseline measurement in other studies.…”

“…This study aims to establish whether brief use of a traditional cradle can elicit psychotic-like experiences, and whether these are related to schizotypal personality traits. In order to measure psychotic-like experiences the study utilized an approach drawn from acute drug studies [7], and that has been used in studies of sensory deprivation [8,9]. The Psychotomimetic States Inventory (PSI [7]) contains items tapping perceptual distortions, delusional thinking, anhedonia, mania, paranoia and cognitive disorganization.…”

Sleep deprivation and hallucinations. A qualitative study of military personnel

“…In this regard, Belenky (1979) states that reducing social isolation and increasing sensory simulation would improve performance during sustained operations. The fact that low levels of social and sensory stimulation during sleep deprivation seem to be triggers of hallucinations has some striking reminiscence with hallucinatory experiences that have been reported during studies of sensory deprivation (Daniel, Lovatt, & Mason, 2014). The hallucinatory experiences during sensory deprivation have among others been explained in accordance with the faulty reality monitoring hypothesis (Bentall, 1990) and may suggest that sleep loss impairs the ability to differentiate between internal and external generated stimuli.…”