Sleep spindle activity and psychotic experiences: Examining the mediating roles of attentional performance and perceptual distortions in a daytime nap study.

Decreased sleep spindle activity in individuals with psychotic disorders is well studied, but its contribution to psychotic symptom formation is not well understood. This study explored potential underlying mechanisms explaining the association between decreased sleep spindle activity and psychotic symptoms. To this end, we analysed the links between sleep spindle activity and psychotic experiences and probed for the mediating roles of attentional performance and perceptual distortions in a community sample of young adults (N = 70; 26.33 ± 4.84 years). Polysomnography was recorded during a 90-min daytime nap and duration, amplitude, and density from slow (10-13 Hz) and fast (13-16 Hz) spindles were extracted. Attentional performance was assessed via a test battery and with an antisaccadic eye movement task. Psychotic experiences (i.e., paranoid thoughts; hallucinatory experiences) and perceptual distortions (i.e., anomalous perceptions; sensory gating deficits) were assessed via self-report questionnaires. We conducted sequential mediation analyses with spindle activity as predictor, psychotic experiences as dependent variable, and attentional performance and perceptual distortions as mediators. We found reduced right central spindle amplitude to be associated with paranoid thoughts. Increased antisaccadic error rate was associated with anomalous perceptions and perceptual distortions were associated with psychotic experiences. We did not find significant mediation effects. The findings support the notion that reduced sleep spindle activity is involved in the formation of paranoid thoughts and that decreased antisaccadic performance is indicative of perceptual distortions as potential precursors for psychotic experiences. However, further research is needed to corroborate the proposed mediation hypothesis.

Aberrant adapting of beliefs under stress: a mechanism relevant to the formation of paranoia?

BACKGROUND: Difficulties in the ability to adapt beliefs in the face of new information are associated with psychosis and its central symptom - paranoia. As cognitive processes and psychotic symptoms are both known to be sensitive to stress, the present study investigated the exact associations between stress, adapting of beliefs [reversal learning (RL), bias against disconfirmatory evidence (BADE), and jumping to conclusions (JTC)] and paranoia. We hypothesized that paranoia would increase under stress and that difficulties in adapting of beliefs would mediate or moderate the link between stress and paranoia. Furthermore, we hypothesized that the investigated effects would be strongest in the group of individuals diagnosed with a psychotic disorder. METHODS: We exposed 155 participants (38 diagnosed with a psychotic disorder, 40 individuals with attenuated psychotic symptoms, 39 clinical controls diagnosed with an obsessive-compulsive disorder, and 38 healthy controls) to a control condition and a stress condition, in which we assessed their levels of paranoia and their ability to adapt beliefs. We applied multilevel models to analyze the data. RESULTS: Paranoia was higher in the stress condition than in the control condition, b = 1.142, s.e. = 0.338, t(150) = 3.381, p < 0.001. RL, BADE, and JTC did not differ between conditions and did not mediate or moderate the association between stress and paranoia (all ps > 0.05). CONCLUSIONS: The results support the assumption that stress triggers paranoia. However, the link between stress and paranoia does not seem to be affected by the ability to adapt beliefs.

Pinpointing affective disturbances in psychosis: A comparison of temporal affect dynamics in individuals with psychotic disorders, individuals with attenuated psychotic symptoms, and clinical and healthy controls.

Affective disturbances in psychosis are well-documented but our understanding of their phenotypic nature in everyday life remains limited. Filling this gap could advance mechanistic models of the affective pathway to psychosis and pave the ground for new research avenues. Therefore, this study focused on temporal affect dynamics in psychosis, i.e., the patterns with which affect fluctuates over time. We applied experience-sampling with nine assessments per day over one week in participants with psychotic disorders (PSY), participants with attenuated psychotic symptoms (AS), clinical controls with obsessive compulsive disorders (OCD) and healthy controls (HC; total N = 139) to assess whether in PSY and AS, dynamics in affective valence and arousal are characterized by higher instability (i.e., extreme and frequent moment-to-moment fluctuations of affect intensities), higher affective variability (i.e., larger range of affect intensities), or lower inertia (i.e., higher frequency of affective changes), compared to the clinical and healthy control samples. Mixed-model ANOVAs revealed higher instability in both PSY and OCD compared to HC, but no significant differences for variability and inertia. AS had an intermediate position and did not differ significantly from any other group. We found evidence for small to medium effect sizes for the influence of mean affect levels on the dynamic indicators. Our findings indicate that individuals with psychotic disorders have increased affective instability and that this could be a transdiagnostic phenomenon. Zooming in on the variability and inertia components did not confer additional benefits. Emotion-focused interventions for psychosis should focus on reducing frequent and extreme affective fluctuations.

Sleep and circadian rhythm disruption predict persecutory symptom severity in day-to-day life: A combined actigraphy and experience sampling study.

Sleep-related problems are prevalent in patients with psychotic disorders, yet their contribution to fluctuations in delusional experiences is less clear. This study combined actigraphy and experience-sampling methodology (ESM) to capture the relation between sleep and next-day persecutory symptoms in patients with psychosis and prevailing delusions. Individuals with current persecutory delusions (PD; n = 67) and healthy controls (HC; n = 39) were assessed over 6 consecutive days. Objective sleep and circadian rhythm measures were assessed using actigraphy. Every morning upon awakening, subjective sleep quality was measured using ESM. Momentary assessments of affect and persecutory symptoms were gathered at 10 random time points each day using ESM. Robust linear mixed modeling was performed to assess the predictive value of sleep measures on affect and daytime persecutory symptoms. PD showed significantly lower scores for subjective quality of sleep but significantly higher actigraphic-measured sleep duration and efficiency compared with HC. Circadian rhythm disruption was associated with more pronounced severity of persecutory symptoms in HC. Low actigraphy-derived sleep efficiency was predictive of next-day persecutory symptoms in the combined sample. Negative affect was partly associated with sleep measures and persecutory symptoms. Our results imply an immediate relationship between disrupted sleep and persecutory symptoms in day-to-day life. They also emphasize the relevance of circadian rhythm disruption for persecutory symptoms. Therapeutic interventions that aim to reduce persecutory symptoms could benefit from including modules aimed at improving sleep efficacy, stabilizing sleep-wake patterns, and reducing negative affect. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The relationship between nightmares and psychotic experiences in young adults.

BACKGROUND: There is indication that frequent nightmares are an early indicator of psychotic disorders in adolescents and young adults. Yet which aspects of nightmares are relevant and how they contribute to psychotic experiences has remained unclear. METHODS: We conducted a cross-sectional online survey in a community sample of young adults between the ages of 18 and 27 (n = 486) to identify aspects of nightmares (nightmare frequency (NF), nightmare distress (ND), nightmare contents), that are related to specific psychotic experiences (paranoid thoughts, hallucinations, negative symptoms) after controlling for sleep quality, and examined factors that potentially mediate this relationship (stress, depression). RESULTS: Nightmare frequency and -distress were significantly associated with paranoid thoughts, hallucinations and negative symptoms (NF: rs = 0.293 - 0.139; ND: rs = 0.411 - 0.166). Nightmares significantly added to explaining paranoid thoughts and hallucinations, over and above sleep quality, but not to explaining negative symptoms. The relations between nightmare distress and psychotic experiences were partially mediated by stress (percentage mediated for paranoid thoughts: 38.20%; for hallucinations: 11.77%) and depression (percentage mediated for paranoid thoughts: 56.61%; for hallucinations: 28.02%). The most commonly reported nightmare contents revolved around being chased, falling and losing a close relative and specific contents were significantly related to the frequency of hallucinations (eg, threatening surroundings, OR = 1.73) or paranoia (eg, workspace bullying, OR = 2.02). CONCLUSIONS: Thorough assessments of nightmares and sleep disturbances in young individuals could facilitate early detection of those at risk and help to target preventive treatments. However, longitudinal studies are needed to test for a causal relationship between nightmares and the development of psychotic symptoms.