Are sleep disturbances causally linked to the presence and severity of psychotic-like, dissociative and hypomanic experiences in non-clinical populations? A systematic review

Abstract

The present review aimed to 1) identify what sleep disturbances co-occur alongside psychotic-like, dissociative and hypomanic experiences; 2) assess the strength of potential associations between the severity of sleep disturbances and of the experiences studied; and 3) appraise evidence for a causal link. MedLine and PsycInfo were searched and 44 studies were deemed eligible. Results showed that insomnia was associated with all individual psychotic-like, dissociative and hypomanic experiences reviewed (effect size range: small-to-large). Parasomnias were associated with all psychotic-like experiences; however, there was evidence of variation in magnitude between individual experiences. An eveningness chronotype was associated with dissociative and hypomanic experiences, and circadian dysrhythmia was found alongside hypomania but not the other experiences reviewed. Finally, experimental sleep manipulation studies revealed a potential causal link between sleep loss and psychotic-like and dissociative experiences, although size and consistency of effects varied by specific experience. Future research, using experimental manipulations of sleep to address putative mechanisms, will enable questions of causality to be answered with more confidence.

Poor sleep quality predicts psychotic‐like symptoms: an experience sampling study in young adults with schizotypal traits

“…These findings are in line with the accumulating evidence supporting a link between sleep quality and PLEs . Beyond the consistently reported associations between sleep quality and PLEs in cross‐sectional studies , sleep disturbances seem to precede and predict the appearance of PLEs in non‐clinical populations and individuals at high risk for psychosis .…”

“…Interestingly, our sample on average was characterized by relatively short sleep duration (mean = 6.5) that is below the average sleep duration of university students . This indicates that our sample did not obtain a sufficient amount of sleep that may also be considered a risk factor, especially in individuals with schizotypal tendencies . Future studies may examine whether sleep‐related interventions can reduce the risk of psychosis, especially in high‐risk populations that exhibit PLEs and PLE‐related distress associated with impaired sleep .…”

“…We included the unusual experiences score in the models predicting PLEs, as our aim was to model day‐to‐day variation in PLEs over and above trait‐like differences. Moreover, positive schizotypy has been reported to correlate with poor sleep (e.g., ); thus, in order to control for a trait‐level association between positive schizotypy and self‐reported sleep quality, the unusual experiences score was also included in the models predicting day‐to‐day fluctuation in subjective sleep quality.…”

“…Poor subjective sleep quality refers to the experience of non‐restorative, insufficient, and fragmented sleep leading to sleepiness, fatigue, and tiredness on waking and throughout the day . Epidemiological studies indicate that poor sleep quality as measured by self‐report questionnaires is associated with PLEs . Moreover, poor sleep quality is a strong predictor of the occurrence and persistence of PLEs according to longitudinal assessments of both non‐clinical and clinical participants , and sleep complaints also predict the relapse of psychosis in patients with schizophrenia spectrum disorders , suggesting that the association between sleep quality and psychotic‐like phenomena does not respect boundaries of diagnostic categories.…”

The role of sleep in predicting paranoia in non-affective psychosis: an experience sampling study

“…Symptoms of hypersomnolence such as daytime sleepiness have been reported in people with psychosis ranging from 32-58% [12,13]. These findings coupled with a number of extensive reviews on this topic provides strong evidence that sleep disruption is common in people diagnosed with schizophrenia [14][15][16][17] The relationship between sleep disturbances and paranoia Increased sleep disruption is associated with an increase in level of positive symptoms [1,4]. In particular, strong relationships between sleep disruption and paranoia have being found in both clinical and non-clinical samples [18,19].…”