Non-clinical Psychotic Experiences Research Articles

The impact of aversive personality traits on the psychotic-spectrum of disorders

ObjectivesThough relatively unexplored in clinical populations, aversive personality traits have been shown to impact the expression, the management, and the outcomes of psychotic disorders. This paper seeks to gather and organize existing evidence of the complex interplay linking social ethics, personality and experiences of psychosis through the lens of the so-called Dark Triad personality model, comprising the three multidimensional constructs Machiavellianism, narcissism and psychopathy. MethodsA semi-systematic review of major literature databases was conducted; search terms aimed at capturing each of the Dark Triad dimensions and their known relations with both clinical (with single-symptom approach) and non-clinical psychotic experiences. ResultsReviewed studies suggest that all the components of the Dark Triad model present significant clinical implications in the management of psychotic disorders. ConclusionsAversive personality traits interact with and modulate the experiences of psychosis. They can be shown to influence the clinical and functional outcomes of psychotic patients. Therefore, further research on this theme seems justified in that it may inform rehabilitative efforts.

Atopy Increases Risk of Psychotic Experiences: A Large Population-Based Study.

Introduction: Building upon the comorbidity between atopy and schizophrenia, we conducted a large cross-sectional, observational population-based study to examine if such associations also exist between atopic disorders (eczema, allergic rhinitis, and asthma) and nonclinical psychotic experiences. Methods: We examined psychotic experiences in a Dutch population sample through an online survey (≥14 years of age). Participants filled out the Questionnaire for Psychotic Experiences, together with questions screening for atopic disorders (eczema, allergic rhinitis, and asthma). Prevalence rates were calculated; binary logistic regression was used to determine odds ratios (ORs) (age, gender, and years of education as covariates). Results: We included 6,479 participants. Individuals diagnosed with one or more atopic disorders had an increased risk of psychotic experiences as compared with controls (OR = 1.26). Analysis of individual symptoms revealed an OR of 1.27 for hallucinations, whereas delusions only showed a trend. With each additional atopic disorder, the risk of psychotic experiences increased. This was also observed for hallucinations alone but not for delusions alone. Atopy was associated with hallucinations across all modalities (OR ranging from 1.19 to 1.40). These results did not appear to be driven specifically by any one of the atopic disorders. Conclusion: In the largest population sample of adolescents and adults to date, we found that atopic disorders (asthma, eczema, and allergic rhinitis) increase the risk of psychotic experiences, in a dose–response fashion. These results provide further support for the role of immunological components in the predisposition for psychosis and can serve as a base for further research.

Does childhood trauma play a role in the aetiology of psychosis? A review of recent evidence

SummaryThere has been a resurgence of interest in the role of childhood trauma in the aetiology of psychosis. In this review, recent findings on the association between childhood trauma and a continuum of psychotic symptoms are presented. Evidence of the association between specific childhood trauma subtypes and psychotic symptoms is examined, with a brief discussion of some current hypotheses about the potential mechanisms underlying the associations that have been found. Some practice implications of these findings are also highlighted.Learning Objectives• Identify findings from recent meta-analyses on the association between childhood trauma and a range of psychotic outcomes, from non-clinical psychotic experiences to psychotic disorders• Consider which childhood traumas are the most potent in the context of psychotic outcomes• Recognise that the relationships between childhood trauma, psychotic symptoms and other psychopathology are complex, dynamic and multidimensional

Memory binding in clinical and non-clinical psychotic experiences: How does the continuum model fare?

Introduction. Both clinical and non-clinical auditory hallucinations (AH) have been associated with source memory deficits, supporting a continuum of underlying cognitive mechanisms, though few studies have employed the same task in patient and nonpatient samples. Recent commentators have called for more debate on the continuum model of psychosis. Consequently, the current study investigated the continuity model of AH with reference to memory binding. Methods. We used an identical voice and word recognition memory task to assess binding in two separate studies of: (1) healthy hallucination-prone individuals and controls (30 high and 30 low scorers on the Launay-Slade Hallucination Scale–Revised) and (2) schizophrenia patient samples (32 with AH, 32 without AH) and 32 healthy controls. Results. There was no evidence of impaired binding in high hallucination-prone, compared to low hallucination-prone individuals. In contrast, individuals with schizophrenia (both with and without AH) had difficulties binding (remembering “who said what”), alongside difficulties remembering individual words and voices. Binding ability and memory for voices were also negatively linked to the loudness of hallucinated voices reported by patients with AH. Conclusions. These findings suggest that different mechanisms may exist in clinical and non-clinical hallucinators, adding to the growing debate on the continuum model of psychotic symptoms.

Self-perception but not peer reputation of bullying victimization is associated with non-clinical psychotic experiences in adolescents

Bullying victimization may be linked to psychosis but only self-report measures of victimization have been used so far. This study aimed (a) to investigate the differential associations of peer-nominated versus self-reported victim status with non-clinical psychotic experiences in a sample of young adolescents, and (b) to examine whether different types of self-reported victimization predict non-clinical psychotic experiences in these adolescents. Method A combination of standard self-report and peer nomination procedures was used to assess victimization. The sample (n = 724) was divided into four groups (exclusively self-reported victims, self- and peer-reported victims, exclusively peer-reported victims, and non-victims) to test for a group effect on non-clinical psychotic experiences. The relationship between types of victimization and non-clinical psychotic experiences was examined by a regression analysis. Self-reported victims, along with self- and peer-reported victims, scored higher than peer-reported victims and non-victims on non-clinical psychotic experiences. Self-reports of direct relational, indirect relational and physical victimization significantly improved the prediction of non-clinical psychotic experiences whereas verbal and possession-directed victimization had no significant predictive value. The relationship between victimization and non-clinical psychotic experiences is only present for self-reported victimization, possibly indicative of an interpretation bias. The observed discrepancy between self-report and peer-report highlights the importance of implementing a combination of both measures for future research.

Serum 25-Hydroxyvitamin D3 and D2 and Non-Clinical Psychotic Experiences in Childhood

ObjectiveNon-clinical psychotic experiences are common and distressing. It has been hypothesized that early life vitamin D deficiency may be a risk factor for psychosis-related outcomes, but it is not known if circulating concentrations of 25-hydroxyvitamin D (25(OH)D) during childhood are associated with psychosis-related outcomes or whether the two different forms of 25(OH)D, (25(OH)D3 and 25(OH)D2, have similar associations with psychosis-related outcomes.MethodsWe investigated the association between serum 25(OH)D3 and 25(OH)D2 concentrations and psychotic experiences in a prospective birth cohort study. Serum 25(OH)D3 and 25(OH)D2 concentrations were measured at mean age 9.8 years and psychotic experiences assessed at mean age 12.8 years by a psychologist (N = 3182).ResultsHigher 25(OH)D3 concentrations were associated with lower risk of definite psychotic experiences (adjusted odds ratio: OR (95% confidence interval: CI) 0.85 (0.75–0.95)). Higher concentrations of 25(OH)D2 were associated with higher risk of suspected and definite psychotic experiences (adjusted odds ratio: OR (95% confidence interval: CI) 1.26 (1.11, 1.43)). Higher 25(OD)D2 concentrations were also weakly associated with definite psychotic experiences (adjusted OR (95% CI) 1.17 (0.96, 1.43), though with wide confidence intervals including the null value.ConclusionsOur findings of an inverse association of 25(OH)D3 with definite psychotic experiences is consistent with the hypothesis that vitamin D may protect against psychosis-related outcomes.

Daily cortisol, stress reactivity and psychotic experiences in individuals at above average genetic risk for psychosis

Hypothalamic-pituitary-adrenocortical (HPA) axis abnormalities have been found in patients with a psychotic disorder and first-degree relatives of patients with a psychotic disorder react with subtle increases in non-clinical psychotic experiences and negative emotions in the face of everyday stress. The current study investigated whether HPA axis functioning is altered in individuals at above average genetic risk for psychotic disorder, examining diurnal cortisol profiles, cortisol reactivity to daily stressors and the association between HPA axis activity and subclinical psychotic experiences. Participants included siblings of patients with a psychotic disorder (n=60) and a healthy comparison group (n=63). The Experience Sampling Method (a structured diary technique) was employed to assess stress, psychotic experiences, negative affect and salivary cortisol repeatedly in the flow of daily life. Multi-level analyses revealed higher diurnal cortisol levels and heightened cortisol reactivity to negative daily events in siblings compared with controls. Diurnal cortisol slope did not differ between the two groups, but momentary increases in psychotic experiences and negative affect were associated with increased cortisol in the sibling group. Findings support altered HPA axis activity in individuals at above average genetic risk for psychotic disorder, as evidenced by higher diurnal cortisol levels and increased cortisol reactivity to daily stress. Results also suggest a dynamic association between cortisol secretion and the intensity of psychotic-like experiences and negative emotions in daily life, although the direction of this association remains to be elucidated.

Perinatal folate-related exposures and risk of psychotic symptoms in the ALSPAC birth cohort

BackgroundIt is unclear to what extent non-clinical psychotic experiences during childhood and adolescence share underlying aetiological mechanisms with schizophrenia. One candidate mechanism for schizophrenia involves the epigenetic status of the developing fetus, which depends on the internal folate-status of mother and child. Our study examines the relationships between multiple determinants of perinatal folate-status and development of psychotic experiences in adolescence. MethodsStudy participants were up to 5344 mother–child pairs from the Avon Longitudinal Study of Parents and their Children, UK, with information on maternal and/or child MTHFR C677T genotype, maternal folate intake (supplementation at 18/32- weeks gestation; dietary intake at 32- weeks gestation) and psychosis-like symptoms (PLIKS) for children assessed at age 12. ResultsNominal evidence was observed that maternal folate supplementation at 18weeks increased the odds of PLIKS in children (odds ratio(OR)=1.34; 95%-CI:[1.00;1.76]) and, consistent with this, that children of MTHFR C667T TT homozygous mothers had decreased odds of PLIKS (OR=0.72; 95%CI:[0.50;1.02]; recessive model) with strongest effects in boys (OR=0.44, 95%-CI:[0.22;0.79]; sex-specific p=0.029). None of the reported effects remained significant when corrected for multiple testing. ConclusionsOverall, this study found no support that maternal/child MTHFR C677T genotype and maternal folate intake during pregnancy contribute to common aetiological pathways that are shared between schizophrenia and non-clinical psychotic symptoms in adolescents, assuming that decreased folate-status increases schizophrenia risk.

Maternal tobacco, cannabis and alcohol use during pregnancy and risk of adolescent psychotic symptoms in offspring

Adverse effects of maternal substance use during pregnancy on fetal development may increase risk of psychopathology. To examine whether maternal use of tobacco, cannabis or alcohol during pregnancy increases risk of offspring psychotic symptoms. A longitudinal study of 6356 adolescents, age 12, who completed a semi-structured interview for psychotic symptoms in the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. Frequency of maternal tobacco use during pregnancy was associated with increased risk of suspected or definite psychotic symptoms (adjusted odds ratio 1.20, 95% CI 1.05-1.37, P = 0.007). Maternal alcohol use showed a non-linear association with psychotic symptoms, with this effect almost exclusively in the offspring of women drinking >21 units weekly. Maternal cannabis use was not associated with psychotic symptoms. Results for paternal smoking during pregnancy and maternal smoking post-pregnancy lend some support for a causal effect of tobacco exposure in utero on development of psychotic experiences. These findings indicate that risk factors for development of non-clinical psychotic experiences may operate during early development. Future studies of how in utero exposure to tobacco affects cerebral development and function may lead to increased understanding of the pathogenesis of psychotic phenomena.

Evidence that self‐reported psychotic experiences represent the transitory developmental expression of genetic liability to psychosis in the general population

It has been suggested that self-reported, common, non-clinical psychotic experiences may represent the transitory developmental expression of distributed genetic risk for psychosis. In a sample of female MZ (176 pairs) and DZ twins (113 pairs), cross-twin, cross-trait analyses were conducted to investigate the association between repeated continuous measures of self-reported psychotic experiences (PE-three measures over 18 months), assessed with the CAPE, in one twin and clinical interview categorical measures of psychotic symptoms (PS), assessed with SCID-I, in the other twin. The results showed that in MZ but not DZ pairs (interaction: chi(2) = 7.9, df = 1, P = 0.005), the cross-twin association between PE and PS was large and significant (standardized effect size: 0.26, 95% CI: 0.10-0.42) and of similar magnitude as the within-twin PE-PS association (standardized effect size: 0.28, 95% CI: 0.10-0.45), demonstrating both PE validity and genetic effects. In addition, the cross-twin association between PE and PS was significantly larger (interaction: chi(2) = 20.3, df = 1, P < 0.0001) for younger MZ twins (standardized effect size: 0.67, 95% CI: 0.44-0.90) than older MZ twins (standardized effect size: -0.05, 95% CI: -0.26 to 0.16), demonstrating developmental effects. This study indicates that self-reported psychotic experiences in the general population may represent the developmental expression of population genetic risk for psychosis.

Childhood victimisation and developmental expression of non-clinical delusional ideation and hallucinatory experiences

Victimisation in childhood may be associated with adult psychosis. The current study examined this association in the crucial developmental period of early adolescence and investigated whether (1) unwanted sexual experiences, and (2) being bullied, were associated with non-clinical delusional ideation and hallucinatory experiences in a general population sample of 14 year olds. Data were derived from standard health screenings of the Youth Health Care Divisions of the Municipal Health Services in Maastricht, the Netherlands. A self-report questionnaire was filled out by a total of 1290 adolescents to assess non-clinical psychotic experiences, as well as experiences of being bullied and sexual trauma. Non-clinical psychotic experiences were strongly and independently associated with both bullying (OR=2.9, 95% CI 1.8-4.8) and sexual trauma (OR=4.8, 95% CI 2.3-10.1). The results suggest that reported associations between childhood victimisation and adult psychosis can be understood in a developmental framework of onset of at-risk mental states in early adolescence. In addition, the data suggest that the traumatic experience of being bullied may also feed the cognitive and biological mechanisms underlying formation of psychotic ideation.

Early trauma may increase the risk for psychotic experiences by impacting on emotional response and perception of control

Exposure to early trauma may increase the risk of dysfunctional responses to anomalous psychotic experiences resulting in psychotic symptom formation. In a three-wave longitudinal general population study, 4045 never-psychotic individuals exposed and non-exposed to trauma before the age of 16 years, according to baseline interview were interviewed for the onset of psychotic experiences 3 years later (T2). In 36 individuals with incident psychosis at T2, assessments were made, for each psychotic experience, of i) the amount of distress associated with and ii) the degree of coping and subjective control over the experience. In the 16 observations of an incident psychotic experience, in the absence of distress, the baseline rate of early trauma was low (6%), whereas it was much higher in the 21 observations of an incident psychotic experience with distress [43%; odds ratio=10.0, 95% confidence interval (CI): 1.04, 96.3; P=0.046]. Similarly, coping attempts in the context of early trauma was associated with less control (reduction of 2 points on a seven-point scale, 95% CI: -4.0, -0.07). Early experience of trauma may create lasting cognitive and affective vulnerabilities to develop clinical symptoms arising out of early, non-clinical psychotic experiences.