Sleep duration and psychotic experiences in patients at risk of psychosis: A secondary analysis of the EDIE-2 trial

Bidirectional associations between short sleep duration, insomnia symptoms, and psychotic-like experiences in adolescents

This study investigates the prospective associations between short sleep duration, insomnia symptoms, and psychotic-like experiences (PLEs) in a large sample of Chinese adolescents. This study utilized a three-timepoint repeated cross-sectional survey with two nested longitudinal subsamples. A total of 17,722 adolescents were assessed at baseline (April 21 to May 12, 2021) and six months later (December 17 to 26, 2021). Out of these, 15,694 adolescents provided complete responses to the questions at baseline and one year later (May 17 - June 6, 2022). A self-administered questionnaire was used to measure sample characteristics (at baseline), sleep duration, insomnia symptoms, and PLEs (at each assessment), and negative life events (at two follow-ups). Baseline short sleep duration and insomnia symptoms predicted frequent PLEs at both follow-up assessments. Additionally, baseline frequent PLEs also predicted insomnia symptoms at six months and one year later. However, when controlling for confounders, PLEs at baseline only predicted short sleep duration at six months, and not at one year. This study reveals bidirectional prospective relationships between short sleep duration, insomnia symptoms, and PLEs, even after controlling for covariates. Therefore, it is crucial to assess both sleep patterns and PLEs in order to promote optimal sleep and mental health among adolescents.

Impaired Sleep Mediates the Relationship Between Interpersonal Trauma and Subtypes of Delusional Ideation

BACKGROUND AND HYPOTHESIS

Trauma is a robust risk factor for delusional ideation. However, the specificity and processes underlying this relationship are unclear. Qualitatively, interpersonal traumas (i.e., trauma caused by another person) appear to have a specific relationship with delusional ideation, particularly paranoia, given the commonality of social threat. However, this has not been empirically tested and the processes by which interpersonal trauma contributes to delusional ideation remain poorly understood. Given the role of impaired sleep in both trauma and delusional ideation, it may be a critical mediator between these variables. We hypothesized that interpersonal trauma, but not non-interpersonal trauma, would be positively related to subtypes of delusional ideation, especially paranoia, and that impaired sleep would mediate these relationships.

STUDY DESIGN

In a large, transdiagnostic community sample (N = 478), an exploratory factor analysis of the Peter's Delusion Inventory identified three subtypes of delusional ideation, namely magical thinking, grandiosity, and paranoia. Three path models, one for each subtype of delusional ideation, tested whether interpersonal trauma and non-interpersonal trauma were related to subtypes of delusional ideation, and impaired sleep as a mediating variable of interpersonal trauma.

STUDY RESULTS

Paranoia and grandiosity were positively related to interpersonal trauma and unrelated to non-interpersonal trauma. Furthermore, these relationships were significantly mediated by impaired sleep, which appeared strongest for paranoia. In contrast, magical thinking was unrelated to traumatic experiences.

CONCLUSIONS

These findings support a specific relationship between interpersonal trauma and paranoia as well as grandiosity, with impaired sleep appearing as an important process by which interpersonal trauma contributes to both.

Associations between disturbed sleep and attenuated psychotic experiences in people at clinical high risk for psychosis

BACKGROUND

Pre-diagnostic stages of psychotic illnesses, including 'clinical high risk' (CHR), are marked by sleep disturbances. These sleep disturbances appear to represent a key aspect in the etiology and maintenance of psychotic disorders. We aimed to examine the relationship between self-reported sleep dysfunction and attenuated psychotic symptoms (APS) on a day-to-day basis.

METHODS

Seventy-six CHR young people completed the Experience Sampling Methodology (ESM) component of the European Union Gene-Environment Interaction Study, collected through PsyMate® devices, prompting sleep and symptom questionnaires 10 times daily for 6 days. Bayesian multilevel mixed linear regression analyses were performed on time-variant ESM data using the brms package in R. We investigated the day-to-day associations between sleep and psychotic experiences bidirectionally on an item level. Sleep items included sleep onset latency, fragmentation, and quality. Psychosis items assessed a range of perceptual, cognitive, and bizarre thought content common in the CHR population.

RESULTS

Two of the seven psychosis variables were unidirectionally predicted by previous night's number of awakenings: every unit increase in number of nightly awakenings predicted a 0.27 and 0.28 unit increase in feeling unreal or paranoid the next day, respectively. No other sleep variables credibly predicted next-day psychotic symptoms or vice-versa.

CONCLUSION

In this study, the relationship between sleep disturbance and APS appears specific to the item in question. However, some APS, including perceptual disturbances, had low levels of endorsement amongst this sample. Nonetheless, these results provide evidence for a unidirectional relationship between sleep and some APS in this population.

Alexithymia is associated with insomnia in Chinese patients with schizophrenia

Background

Sleep disorders are prevalent among patients with schizophrenia and are associated with several negative consequences. Although, researchers have recently suggested that sleep disorders have a close correlation with alexithymia, and schizophrenia also has a strong correlation with alexithymia, there have been few studies on the relationships between schizophrenia, sleep disorders and alexithymia. Therefore, this study aimed to explore the relationships between psychiatric symptoms, alexithymia and sleep problems in patients with schizophrenia so as to provide a reference for the clinical treatment of this comorbidity.

Methods

In total, 977 patients with schizophrenia were recruited for this study. The Insomnia Severity Index (ISI) was used to assess sleep disorders, and the Positive and Negative Syndrome Scale (PANSS), Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Toronto Alexithymia Scale (TAS) were used to evaluate clinical symptoms, cognitive functions and the ability to express emotion, respectively.

Results

The results indicated that the PANSS subscales (G-subscore) and TAS group were risk factors for insomnia in schizophrenia patients (all p < 0.05). The mediation model showed the standardized path coefficients from schizophrenia to alexithymia (β = 0.104, p < 0.001) and from alexithymia to insomnia (β = 0.038, p < 0.001) were statistically significant.

Conclusion

The results of this study indicated that alexithymia is associated with sleep disturbance in patients with schizophrenia. These findings may provide a new avenue for the treatment of schizophrenia patients with sleep disorders.

Multivariate patterns of disrupted sleep longitudinally predict affective vulnerability to psychosis in 22q11.2 Deletion Syndrome

22q11.2 deletion syndrome (22q11DS) contributes dramatically to increased genetic risk for psychopathology, and in particular schizophrenia. Sleep disorders, including obstructive sleep apnea (OSA), are also highly prevalent, making 22q11DS a unique model to explore their impact on psychosis vulnerability. Still, the contribution of sleep disturbances to psychosis vulnerability remains unclear. We characterized the sleep phenotype of 69 individuals with 22q11DS and 38 healthy controls with actigraphy and sleep questionnaires. Psychiatric symptoms were measured concomitantly with the baseline sleep assessment and at longitudinal follow-up, 3.58±0.85 years later. We used a novel multivariate partial-least-square-correlation (PLSC) approach to identify sleep patterns combining objective and subjective variables, which correlated with psychiatric symptoms. We dissected longitudinal pathways linking sleep disturbances to psychosis, using multi-layer-network-analysis. 22q11DS was characterized by a non-restorative sleep pattern, combining increased daytime fatigue despite longer sleep duration. Non-restorative sleep combined with OSA symptoms correlated with both emotional and psychotic symptoms. Moreover, a sleep pattern evocative of OSA predicted longitudinal worsening of positive and negative symptoms, by accentuating the effects of emotional dysregulation. These results suggest that sleep disturbances could significantly increase psychosis risk, along an affective pathway. If confirmed, this suggests that systematic screening of sleep quality could mitigate psychosis vulnerability in 22q11DS.

The longitudinal relationship between sleep length and psychotic-like experiences in adolescents

The longitudinal relationship between psychotic-like experiences (PLEs) and short habitual sleep in adolescents remains to be investigated. We examined the effect of habitual sleep length (time-in-bed: TIB) on the risk of subsequent year PLEs and vice versa, in grade 7-12 students (ages: 12-18, n = 1,685) followed over 6 years. Yearly longitudinal data were analyzed using cross-lagged panel models. Shorter weekday TIB was associated with a higher risk of subsequent year PLEs; PLEs did not affect subsequent year TIB. Compared to a TIB of 8-9 h, 5-6 h increased PLEs likelihood 1.8 times; <5 h increased this 6-fold.

Adolescent sleep and the foundations of prefrontal cortical development and dysfunction

Modern life poses many threats to good-quality sleep, challenging brain health across the lifespan. Curtailed or fragmented sleep may be particularly damaging during adolescence, when sleep disruption by delayed chronotypes and societal pressures coincides with our brains preparing for adult life via intense refinement of neural connectivity. These vulnerabilities converge on the prefrontal cortex, one of the last brain regions to mature and a central hub of the limbic-cortical circuits underpinning decision-making, reward processing, social interactions and emotion. Even subtle disruption of prefrontal cortical development during adolescence may therefore have enduring impact. In this review, we integrate synaptic and circuit mechanisms, glial biology, sleep neurophysiology and epidemiology, to frame a hypothesis highlighting the implications of adolescent sleep disruption for the neural circuitry of the prefrontal cortex. Convergent evidence underscores the importance of acknowledging, quantifying and optimizing adolescent sleep's contributions to normative brain development and to lifelong mental health.

No rest for the weary: Prevalence, impact and nature of sleep problems among young people at risk of psychosis

AIMS

Sleep problems are common in people with a psychosis-spectrum diagnosis and are associated with worse psychotic symptoms and lower quality of life. Sleep problems are also frequent in individuals at a clinical high risk for psychosis (CHR-P) however, less is known about the prevalence and association with symptoms in this population. This study investigates the prevalence of sleep problems within CHR-P individuals and the associations with attenuated positive symptoms, transition to psychosis, time to transition to psychosis and functioning.

METHODS

The clinical records interactive search (CRIS) tool was used to carry out a retrospective study of 795 CHR-P individuals. Sleep problems, subsequent psychotic diagnoses, attenuated positive symptoms and Health of The Nation Outcome Scale scores were extracted. Regression models were used to examine the association between sleep problems and clinical outcomes.

RESULTS

59.5% of CHR-P individuals experienced sleep problems. Perceptual abnormality severity (OR = 1.24, 95% CI = 1.05-1.48) and frequency (OR = 1.31, 95% CI = 1.08-1.58) as measured by the Comprehensive Assessment of At-Risk Mental State interview, predicted sleep problems. Sleep problems were not associated with transition to psychosis; however, they were significantly associated with a shorter time to transition in individuals who developed psychosis (HR = 1.4, 95% CI = 1.05-1.88) and higher follow-up Health of the Nation Outcome Scale scores (MD = 2.26, 95% CI = 0.55-3.96).

CONCLUSIONS

The high prevalence of sleep problems, along with the association with positive symptoms and worse functioning, highlights the need for effective sleep interventions in this population. Further research is needed to better understand the relationship between sleep problems and transition to psychosis.

The nature, consequences, mechanisms, and management of sleep disturbances in individuals at-risk for psychosis

There is strong evidence that sleep disturbances are commonly experienced by people with psychosis. Evidence has also shown that sleep disturbances are present since the very early stages of the disease, even during the pre-diagnostic phase. More recently, research involving young individuals at ultra-high risk (UHR) for psychosis documented frequent occurrence of sleep disturbances in this group. The very early onset of sleep disturbances in the course of psychosis has drawn attention to the possible links between sleep parameters and the risk of psychosis. To date, the nature of sleep disturbances characterizing the UHR stage remains unclear, with available studies having yielded mixed findings. In this regard, we performed this review to update the body of literature on the nature of sleep disturbances, their underlying mechanisms, their clinical and functional consequences, the prevention and intervention strategies in the at-risk for psychosis population. Our findings provided further support to the presence of disturbed sleep in UHR individuals as evidenced by subjective and objective sleep measures such as polysomnography, sleep electroencephalograms, and actigraphy. Reviewing the possible mechanisms underlying the relationship between sleep and psychosis emphasized its complex and multifactorial nature which is yet to be determined and understood. Further research is warranted to determine which facets of sleep disturbances are most detrimental to this specific population, and to what extent they can be causal factors or markers of psychosis.

Improving sleep quality leads to better mental health: A meta-analysis of randomised controlled trials

The extent to which sleep is causally related to mental health is unclear. One way to test the causal link is to evaluate the extent to which interventions that improve sleep quality also improve mental health. We conducted a meta-analysis of randomised controlled trials that reported the effects of an intervention that improved sleep on composite mental health, as well as on seven specific mental health difficulties. 65 trials comprising 72 interventions and N = 8608 participants were included. Improving sleep led to a significant medium-sized effect on composite mental health (g+ = -0.53), depression (g+ = -0.63), anxiety (g+ = -0.51), and rumination (g+ = -0.49), as well as significant small-to-medium sized effects on stress (g+ = -0.42), and finally small significant effects on positive psychosis symptoms (g+ = -0.26). We also found a dose response relationship, in that greater improvements in sleep quality led to greater improvements in mental health. Our findings suggest that sleep is causally related to the experience of mental health difficulties. Future research might consider how interventions that improve sleep could be incorporated into mental health services, as well as the mechanisms of action that explain how sleep exerts an effect on mental health.

Characterizing the Genetic Overlap Between Psychiatric Disorders and Sleep-Related Phenotypes

BACKGROUND

A range of sleep disturbances are commonly experienced by patients with psychiatric disorders, and genome-wide genetic analyses have shown some significant genetic correlations between these traits. Here, we applied novel statistical genetic methodologies to better characterize the potential shared genetic architecture between sleep-related phenotypes and psychiatric disorders.

METHODS

Using the MiXeR method, which can estimate polygenic overlap beyond genetic correlation, the shared genetic architecture between major psychiatric disorders (bipolar disorder [N = 51,710], depression [N = 480,359], and schizophrenia [N = 77,096]) and sleep-related phenotypes (chronotype [N = 449,734], insomnia [N = 386,533] and sleep duration [N = 446,118]) were quantified on the basis of genetic summary statistics. Furthermore, the conditional/conjunctional false discovery rate framework was used to identify specific shared loci between these phenotypes, for which positional and functional annotation were conducted with FUMA.

RESULTS

Extensive genetic overlap between the sleep-related phenotypes and bipolar disorder (63%-77%), depression (76%-79%), and schizophrenia (64%-79%) was identified, with moderate levels of congruence between most investigated traits (47%-58%). Specific shared loci were identified for all bivariate analyses, and a subset of 70 credible genes were mapped to these shared loci.

CONCLUSIONS

The current results provide evidence for substantial polygenic overlap between psychiatric disorders and sleep-related phenotypes, beyond genetic correlation (|r_g| = 0.02 to 0.42). Moderate congruency within the shared genetic components suggests a complex genetic relationship and potential subgroups with higher or lower genetic concordance. This work provides new insights and understanding of the shared genetic etiology of sleep-related phenotypes and psychiatric disorders and highlights new opportunities and avenues for future investigation.

Examining self-reported social functioning, sleep quality, and psychotic-like experiences in college students

Impairments in social and role functioning have been associated with the prodromal phase of psychosis. Additionally, sleep disturbances impacting daily functioning have been detected across the schizophrenia spectrum. Relationships between social functioning, sleep quality, and psychotic-like experiences (PLEs) in undergraduate-level student populations are less understood. The current project aimed to investigate whether self-reported measures of sleep quality would moderate the relationship between social functioning and PLE endorsement in a community sample of 3042 undergraduate student participants between the ages of 18-35. Participants completed the Social Functioning Scale, the Pittsburgh Sleep Quality Index, and the Prodromal Questionnaire, which indexed PLEs. Bivariate correlations revealed significant associations between social functioning, sleep, and PLEs. As expected, poor sleep and poor social functioning were associated with increased endorsement of PLEs. Contrary to expectation, poor sleep quality was associated with better social functioning. In hierarchical multiple regression models, the interaction between social functioning and sleep was not associated with PLE endorsement. Results indicated that both poor sleep and poor social functioning were significantly associated with PLEs when included in the same model. These findings suggest that poor social functioning and disrupted sleep may act additively to influence PLEs, and that they are both important contributors to psychotic symptoms. Due to deleterious effects of poor sleep on physical and emotional health, these findings provide impetus to further investigate relationships between sleep quality, social functioning, and PLEs using such high-resolution methods as actigraphy, mobile sensing, ecological momentary assessment, and neuroimaging.

Sleep Abnormalities in Schizophrenia: State of the Art and Next Steps

Sleep disturbances are commonly observed in schizophrenia, including in chronic, early-course, and first-episode patients. This has generated considerable interest, both in clinical and research endeavors, in characterizing the relationship between disturbed sleep and schizophrenia. Sleep features can be objectively assessed with EEG recordings. Traditionally, EEG studies have focused on sleep architecture, which includes non-REM and REM sleep stages. More recently, numerous studies have investigated alterations in sleep-specific rhythms, including EEG oscillations, such as sleep spindles and slow waves, in individuals with schizophrenia compared with control subjects. In this article, the author reviews state-of-the-art evidence of disturbed sleep in schizophrenia, starting from the relationship between sleep disturbances and clinical symptoms. First, the author presents studies demonstrating abnormalities in sleep architecture and sleep-oscillatory rhythms in schizophrenia and related psychotic disorders, with an emphasis on recent work demonstrating sleep spindles and slow-wave deficits in early-course and first-episode schizophrenia. Next, the author shows how these sleep abnormalities relate to the cognitive impairments in patients diagnosed with schizophrenia and point to dysfunctions in underlying thalamocortical circuits, Ca+ channel activity, and GABA-glutamate neurotransmission. Finally, the author discusses some of the next steps needed to further establish the role of altered sleep in schizophrenia, including the need to investigate sleep abnormalities across the psychotic spectrum and to establish their relationship with circadian disturbances, which in turn will contribute to the development of novel sleep-informed treatment interventions.

Sleep Disturbance in Individuals at Clinical High Risk for Psychosis

INTRODUCTION

Disturbed sleep is a common feature of psychotic disorders that is also present in the clinical high risk (CHR) state. Evidence suggests a potential role of sleep disturbance in symptom progression, yet the interrelationship between sleep and CHR symptoms remains to be determined. To address this knowledge gap, we examined the association between disturbed sleep and CHR symptoms over time.

METHODS

Data were obtained from the North American Prodrome Longitudinal Study (NAPLS)-3 consortium, including 688 CHR individuals and 94 controls (mean age 18.25, 46% female) for whom sleep was tracked prospectively for 8 months. We used Cox regression analyses to investigate whether sleep disturbances predicted conversion to psychosis up to >2 years later. With regressions and cross-lagged panel models, we analyzed longitudinal and bidirectional associations between sleep (the Pittsburgh Sleep Quality Index in conjunction with additional sleep items) and CHR symptoms. We also investigated the independent contribution of individual sleep characteristics on CHR symptom domains separately and explored whether cognitive impairments, stress, depression, and psychotropic medication affected the associations.

RESULTS

Disturbed sleep at baseline did not predict conversion to psychosis. However, sleep disturbance was strongly correlated with heightened CHR symptoms over time. Depression accounted for half of the association between sleep and symptoms. Importantly, sleep was a significant predictor of CHR symptoms but not vice versa, although bidirectional effect sizes were similar.

DISCUSSION

The critical role of sleep disturbance in CHR symptom changes suggests that sleep may be a promising intervention target to moderate outcome in the CHR state.

Sleep duration and auditory hallucinations: Genetic correlation and two-sample Mendelian randomization study

OBJECTIVES

Previous studies have found that sleep problems are associated with psychotic experiences (PEs) across clinical designs, but many confounding factors from uncertain variables have been unclear in observational designs. The aim of the present study was to detect the genetic correlations and causal relationship between sleep-related traits and PEs using the largest current genome-wide association study (GWAS) summary statistics.

METHODS

GWAS results were obtained for positive PEs (N = 116,787-117,794) and sleep-related traits [insomnia complaints (N = 386,533), morningness (N = 345,552), sleep duration (N = 384,317), ease of getting up in the morning (N = 385,949), daytime napping (N = 386,577), daytime sleepiness (N = 386,548), and snoring (N = 359,916)]. Linkage disequilibrium score regression (LDSC) was used to investigate genetic correlations. Mendelian randomization (MR) was conducted on trait pairs with significant genetic associations.

RESULTS

We found that auditory hallucinations were significantly genetically correlated with insomnia complaints (rg = -0.27, p = 1.1 × 10^-3), sleep duration (rg = 0.21, p = 9.7 × 10^-3), and ease of getting up (rg = 0.31, p = 2 × 10^-4). Visual hallucinations and insomnia complaints were highly genetically correlated (rg = 0.36, p = 6.4 × 10^-5). Mendelian randomization indicated a unidirectional causal relationship between sleep duration with auditory hallucinations (β = -0.93, p = 7.9 × 10^-4 for sleep duration as the exposure). We used large GWAS summary statistics across the LDSC and MR programs to determine that sleep duration as exposure to increase the risk of auditory hallucinations.

CONCLUSIONS

Taken together, these findings suggest that treatment of sleep problems should be considered as a higher priority for future mental health services.

Sleep disturbances and first onset of major mental disorders in adolescence and early adulthood: A systematic review and meta-analysis

Despite several high-quality reviews of insomnia and incidence of mental disorders, prospective longitudinal relationships between a wider range of sleep disturbances and first onset of a depressive, bipolar, or psychotic disorders during the peak age range for onset of these conditions has not been addressed. Database searches were undertaken to identify publications on insomnia, but also on other sleep problems such as hypersomnia, short sleep duration, self-identified and/or generic 'sleep problems' and circadian sleep-wake cycle dysrhythmias. We discovered 36 studies that were eligible for systematic review and from these publications, we identified 25 unique datasets that were suitable for meta-analysis (Number>45,000; age ∼17). Individuals with a history of any type of sleep disturbance (however defined) had an increased odds of developing a mood or psychotic disorder in adolescence or early adulthood (Odds ratio [OR]:1.88; 95% Confidence Intervals:1.67, 2.25) with similar odds for onset of bipolar disorders (OR:1.72) or depressive disorders (OR:1.62). The magnitude of associations differed according to type of exposure and was greatest for sleep disturbances that met established diagnostic criteria for a sleep disorder (OR: 2.53). However, studies that examined observer or self-rated symptoms, also reported a significant association between hypersomnia symptoms and the onset of a major mental disorder (OR:1.39). Overall study quality was moderate with evidence of publication bias and meta-regression identified confounders such as year of publication. We conclude that evidence indicates that subjective, observer and objective studies demonstrate a modest but significant increase in the likelihood of first onset of mood and psychotic disorders in adolescence and early adulthood in individuals with broadly defined sleep disturbances. Although findings support proposals for interventions for sleep problems in youth, we suggest a need for greater consensus on screening strategies and for more longitudinal, prospective studies of circadian sleep-wake cycle dysrhythmias in youth.

Treating sleep problems in young people at ultra-high-risk of psychosis: study protocol for a single-blind parallel group randomised controlled feasibility trial (SleepWell)

BACKGROUND

Effective interventions, targeting key contributory causal factors, are needed to prevent the emergence of severe mental health problems in young people. Insomnia is a common clinical issue that is problematic in its own right but that also leads to the development and persistence of psychotic experiences. The implication is that treating sleep problems may prevent the onset of psychosis. We collected initial case series data with 12 young people at ultra-high-risk of psychosis. Post-intervention, there were improvements in sleep, depression and psychotic experiences. Now we test the feasibility of a randomised controlled trial, with a clinical aim to treat sleep problems and hence reduce depression, psychotic experiences, and prevent transition to psychosis.

METHODS AND ANALYSIS

A randomised controlled feasibility trial will be conducted. Forty patients aged 14 to 25 years who are at ultra-high-risk of psychosis and have sleep disturbance will be recruited from National Health Service (NHS) mental health services. Participants will be randomised to receive either a novel, targeted, youth-focussed sleep intervention in addition to usual care or usual care alone. Assessor-blinded assessments will be conducted at baseline, 3 months (post-intervention) and 9 months (follow-up). The eight-session psychological intervention will target the key mechanisms which disrupt sleep: circadian rhythm irregularities, low sleep pressure, and hyperarousal. To gain an in-depth understanding of participants' views on the acceptability of the intervention and study procedures, 16 participants (n=10 intervention, n=6 control) will take part in qualitative interviews. Analyses will focus on feasibility outcomes (recruitment, retention, and treatment uptake rates) and provide initial CI estimates of intervention effects. Thematic analysis of the qualitative interviews will assess the acceptability of the intervention and trial procedures.

ETHICS AND DISSEMINATION

The trial has received ethical approval from the NHS Health Research Authority. Findings will be disseminated through peer-reviewed publications, conference presentations, and lay networks.

TRIAL REGISTRATION NUMBER

ISRCTN85601537.

Sleep and schizophrenia: From epiphenomenon to treatable causal target

BACKGROUND

Sleep disturbance is a common clinical issue for patients with psychosis. It has been identified as a putative causal factor in the onset and persistence of psychotic experiences (paranoia and hallucinations). Hence sleep disruption may be a potential treatment target to prevent the onset of psychosis and reduce persistent psychotic experiences. The aim of this review is to describe developments in understanding the nature, causal role, and treatment of sleep disruption in psychosis.

METHOD

A systematic literature search was conducted to identify studies, published in the last five years, investigating subjective sleep disruption and psychotic experiences.

RESULTS

Fifty-eight papers were identified: 37 clinical and 21 non-clinical studies. The studies were correlational (n = 38; 20 clinical, 18 non-clinical), treatment (n = 7; 1 non-clinical), qualitative accounts (n = 6 clinical), prevalence estimates (n = 5 clinical), and experimental tests (n = 2 non-clinical). Insomnia (50%) and nightmare disorder (48%) are the most prevalent sleep problems found in patients. Sleep disruption predicts the onset and persistence of psychotic experiences such as paranoia and hallucinations, with negative affect identified as a partial mediator of this relationship. Patients recognise the detrimental effects of disrupted sleep and are keen for treatment. All psychological intervention studies reported large effect size improvements in sleep and there may be modest resultant improvements in psychotic experiences.

CONCLUSIONS

Sleep disruption is a treatable clinical problem in patients with psychosis. It is important to treat in its own right but may also lessen psychotic experiences. Research is required on how this knowledge can be implemented in clinical services.

Different patterns of treatment response to Cognitive-Behavioural Therapy for Insomnia (CBT-I) in psychosis

People with psychosis benefit enormously from Cognitive Behavioural Therapy for Insomnia (CBTI), although some variability exists in treatment outcomes. While recent efforts have focused on profiling sleep at treatment initiation, an alternative methodological approach involves using treatment response as a starting point to better understand what constitutes an effective treatment. This study used Grade of Membership analysis (GoM) to estimate the occurrence of unique treatment outcomes and associated patient characteristics. Outcome measures included changes in sleep (self-reported latency, efficiency, duration, quality), functional outcomes (daytime dysfunction, negative mood, need for sleep medication) and treatment goal, collected in 50 individuals with a psychotic disorder and insomnia who underwent CBT-I treatment. Three distinct profiles were identified: (1) Strong responders, who met their treatment goals and showed broad improvements in both sleep and functional domains; (2) Partial responders, who showed sleep improvements (particularly in total sleep time), without noticeable gains in function, and who were predominantly female; and (3) Non-responders who showed little treatment response and failed to meet their treatment goals. This group was also more likely to have greater psychopathology (high levels of negative mood and psychotic symptoms, and antipsychotic medication dosage). These findings suggest that (i) CBT-I can serve to improve sleep and daytime function (although sleep can improve independently from function), (ii) client-elicited treatment goals are a key predictor of CBT-I response, (iii) other important variables associated with treatment response include sleep profile, clinical acuity, and sex.

Sleep disturbance and sleep-related impairment in psychotic disorders are related to both positive and negative symptoms

A large literature indicates that sleep disturbances are associated with paranoia and other positive symptoms in psychotic disorders. However, few studies have examined the potential association between sleep disturbances and negative symptoms and the results have been inconsistent. The current study examined the hypothesis that sleep problems would be associated with more severe positive and negative symptoms in a transdiagnostic sample of individuals with psychosis (N = 90). Further, we examined whether sleep would be related to negative symptoms above and beyond the contribution of paranoia, other positive symptoms, and depression-anxiety. Results replicated prior research in finding that both sleep disturbance and sleep-related impairment were related to more severe paranoia, other positive symptoms and depression-anxiety. Consistent with our hypothesis, more severe sleep disturbance and sleep-related impairment were related to greater negative symptoms; this was evident across both motivation-pleasure deficits and diminished expression. Sleep variables remained significantly related to motivation-pleasure deficits even after controlling for other non-negative symptoms. These results indicate the broad symptom impact of sleep disturbances and may suggest a novel treatment target to improve negative symptoms.

Sleep Problems and Social Impairment in Psychosis: A Transdiagnostic Study Examining Multiple Social Domains

Psychotic disorders are characterized by profound social impairment. An accumulation of research has explored the contribution of symptoms, cognitive functioning, and behavioral skills deficits to this social dysfunction. Recent research indicates that sleep disturbance has significant social implications in nonclinical populations-this research suggests that sleep problems may also be relevant to understanding social impairment in psychosis. This study adopted a symptom-oriented dimensional approach to examine how sleep disturbance and sleep-related impairment are related to multiple social domains within a transdiagnostic sample (N = 90). This sample included individuals with a variety of psychotic disorders (n = 75) along with healthy non-clinical participants (n = 15) to ensure sampling across the full range of sleep problems and social functioning. Social domains spanned self-reported perceptions of social relationships, social functioning in the community, and behavioral assessments of social competence. We hypothesized that greater sleep disturbance and sleep-related impairment would be associated with more negative or problematic perceptions of social relationships (i.e., less social support, less companionship, and greater distress), poorer social functioning in the community, smaller social networks, and poorer behavioral ratings of social competency. Results supported these hypotheses indicating that sleep disturbance and sleep-related impairment have widespread deleterious impacts on perceptions of social relationships, social functioning, and competence. Sleep disturbance retained associations with perceptions of social relationships, social functioning, and social competence even after controlling for total symptoms or cognitive functioning. These findings indicate that sleep problems may have important implications for fully understanding the causes of social impairment in psychosis.

Sleep problems and attenuated psychotic symptoms in youth at clinical high-risk for psychosis

There has been growing interest on the effect of sleep problems on psychotic and prodromal symptoms. The current study investigated cross-sectional relations between sleep problems and attenuated psychotic symptoms in a large sample of 740 youth at Clinical High Risk (CHR) for psychosis in an attempt to replicate previous findings and assess whether findings from general population samples and psychotic samples extend to this CHR sample. Sleep problems were found to be significantly positively associated with attenuated psychotic symptom severity. Sleep problems were also found to be more closely associated with certain specific prodromal symptoms (e.g., suspiciousness and perceptual abnormalities) than other attenuated psychotic symptoms. Further, we found that depression mediated the cross-sectional association between sleep problems and paranoid symptoms only. This adds to a growing body of evidence suggesting the mediation role of depression is more pronounced for paranoid-type psychotic symptoms as compared to other psychotic symptoms (e.g., hallucinations).