ABSTRACT
Introduction: White noise speech illusions index liability for psychotic disorder in case-control comparisons. In the current study, we examined i) the rate of white noise speech illusions in siblings of patients with psychotic disorder and ii) to what degree this rate would be contingent on exposure to known environmental risk factors (childhood adversity and recent life events) and level of known endophenotypic dimensions of psychotic disorder [psychotic experiences assessed with the Community Assessment of Psychic Experiences (CAPE) scale and cognitive ability]. Methods: The white noise task was used as an experimental paradigm to elicit and measure speech illusions in 1,014 patients with psychotic disorders, 1,157 siblings, and 1,507 healthy participants. We examined associations between speech illusions and increasing familial risk (control -> sibling -> patient), modeled as both a linear and a categorical effect, and associations between speech illusions and level of childhood adversities and life events as well as with CAPE scores and cognitive ability scores. Results: While a positive association was found between white noise speech illusions across hypothesized increasing levels of familial risk (controls -> siblings -> patients) [odds ratio (OR) linear 1.11, 95% confidence interval (CI) 1.02-1.21, p = 0.019], there was no evidence for a categorical association with sibling status (OR 0.93, 95% CI 0.79-1.09, p = 0.360). The association between speech illusions and linear familial risk was greater if scores on the CAPE positive scale were higher (p interaction = 0.003; ORlow CAPE positive scale 0.96, 95% CI 0.85-1.07; ORhigh CAPE positive scale 1.26, 95% CI 1.09-1.46); cognitive ability was lower (p interaction < 0.001; ORhigh cognitive ability 0.94, 95% CI 0.84-1.05; ORlow cognitive ability 1.43, 95% CI 1.23-1.68); and exposure to childhood adversity was higher (p interaction < 0.001; ORlow adversity 0.92, 95% CI 0.82-1.04; ORhigh adversity 1.31, 95% CI 1.13-1.52). A similar, although less marked, pattern was seen for categorical patient-control and sibling-control comparisons. Exposure to recent life events did not modify the association between white noise and familial risk (p interaction = 0.232). Conclusion: The association between white noise speech illusions and familial risk is contingent on additional evidence of endophenotypic expression and of exposure to childhood adversity. Therefore, speech illusions may represent a trait-dependent risk marker.
ABSTRACT
OBJECTIVE: The cognitive and motivational impairments observed in psychotic disorders may reflect early developmental alterations that, when combined with later environmental exposures, may drive the onset of positive psychotic symptoms. The epidemiological predictions of this model were tested. METHOD: A longitudinal prospective cohort study (the Early Developmental Stages of Psychopathology Study) was conducted with a representative general population sample of adolescents and young adults from Munich (N=3,021), who were 14-24 years of age at baseline. Sociodemographic factors, environmental exposures, and measures of psychopathology and associated clinical relevance were assessed across three waves, covering a period of up to 10 years, by clinical psychologists using the Composite International Diagnostic Interview. RESULTS: Both negative/disorganized and positive psychotic symptoms were frequent (5-year cumulative prevalence rates of around 12%) and occurred in combination more often than predicted by chance. Negative/disorganized symptoms revealed a pattern of sociodemographic associations indicative of developmental impairment, whereas the positive symptoms were associated with environmental exposures such as trauma, cannabis use, and urbanicity. Negative/disorganized symptoms predicted positive symptoms over time, and co-occurrence of positive and negative/disorganized symptoms was predictive of clinical relevance in terms of secondary functional impairment and help-seeking behavior. CONCLUSION: The results suggest that the negative/disorganized features associated with psychotic disorder are distributed at the population level and drive the ontogenesis of positive psychotic experiences after exposure to environmental risks, increasing the likelihood of impairment and need for care.
