Evidence That Onset of Psychosis in the Population Reflects Early Hallucinatory Experiences That Through Environmental Risks and Affective Dysregulation Become Complicated by Delusions

Schizophrenia Bulletin vol. 38 no. 3 pp. 531–542, 2012 doi:10.1093/schbul/sbq117 Advance Access publication on October 28, 2010 Evidence That Onset of Psychosis in the Population Reflects Early Hallucinatory Experiences That Through Environmental Risks and Affective Dysregulation Become Complicated by Delusions 1 Department of Psychiatry and Psychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University Medical Centre, Maastricht, The Netherlands; 2Clinical Psychology and Epidemiology Unit, Max Planck Institute of Psychiatry, Munich, Germany; 3Epidemiology and Health Psychology, Institute of Psychology, University of Basel, Basel, Switzerland; 4Institute of Clinical Psychology and Psychotherapy, Technical University Dresden, Dresden, Germany; 5Department of Psychosis Studies, Institute of Psychiatry, King’s College London, King’s Health Partners, London, UK * To whom correspondence should be addressed; Department of Psychiatry & Psychology, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands; tel: þ31-43-3875443, fax: þ31-43-3875444, e-mail: Key words: psychosis/delusions/hallucinations/ schizophrenia/prevention/risk Objective: To examine the hypothesis that the ‘‘natural’’ combination of delusions and hallucinations in psychotic disorders in fact represents a selection of early subclinical hallucinatory experiences associated with delusional ideation, resulting in need for care and mental health service use. Methods: In the Early Developmental Stages of Psychopathology study, a prospective, 10-year follow-up of a representative cohort of adolescents and young adults in Munich, Germany (n 5 2524), clinical psychologists assessed hallucinations and delusions at 2 time points (T2 and T3). Analyses compared differences in psychopathology, familial liability for nonpsychotic disorder, nongenetic risk factors, persistence, and clinical outcome between groups characterized by: (1) absence of positive psychotic symptoms, (2) presence of isolated hallucinations, (3) isolated delusions, and (4) both hallucinations and delusions. Results: Delusions and hallucinations occurred together much more often (T2: 3.1%; T3: 2.0%) than predicted by chance (T2: 1.0%; T3: 0.4%; OR 5 11.0; 95% CI: 8.1, 15.1). Content of delusions was contingent on presence of hallucinations but modality of hallucinations was not contingent on presence of delusions. The group with both hallucinations and delusions, compared to groups with either delusions or hallucinations in isolation, displayed the strongest associations with familial affective liability and nongenetic risk factors, as well as with persistence of psychotic symptoms, comorbidity with negative symptoms, affective psychopathology, and clinical need. Conclusions: The early stages of psychosis may involve hallucinatory experiences that, if complicated by delusional ideation under the influence of environmental risks and (liability for) affective dysregulation, give rise to a poor prognosis hallucinatory–delusional syndrome. Introduction The early origins of psychotic illness in the general population remain poorly understood.1 Informative findings come from a handful of prospective general population studies showing that the onset of psychotic disorder can be seen as the outcome of earlier subthreshold expressions of psychotic signs and symptoms.2–4 Study results show that the majority of persons with subthreshold expression of psychotic symptoms (prevalence: 5%–10%5) never convert to psychotic disorder and that in those who do, the number and severity of subthreshold psychotic symptoms, and their degree of persistence, under the influence of environmental exposures such as childhood trauma, cannabis use and an urban environment,6,7 are important predictors.8 Furthermore, not just the presence of psychotic symptoms per se, but the psychopathological and developmental context determines the longer-term outcome, particularly the degree of admixture with affective dysregulation, negative symptoms, and premorbid social dysfunction.9–11 One important hypothesis that has remained difficult to examine empirically regards the relationship between perceptual abnormalities and delusional ideation in the early expression of psychosis. Whilst delusions and hallucinations in psychotic disorder are seen as symptoms that naturally pertaintothesame‘‘class’’ofpositive symptoms,they in fact refer to very different phenomena and there is very Ó The Author 2010. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: . 531 Feikje Smeets1, Tineke Lataster1, Maria-de-Gracia Dominguez1, Juliette Hommes1, Roselind Lieb2,3, Hans-Ullrich Wittchen2,4, and Jim van Os1,5,* F. Smeets et al. 1. Hallucinations and delusions cluster together more often than would be expected by chance. 2. Co-occurrence of delusions and hallucinations, compared to either one in isolation, is more strongly 532 associated with parameters predicting transition to clinical outcome, such as more persistence over time, comorbid affective dysregulation, negative symptoms, suicidal ideation, anxiety, and familial psychopathology. 3. Although it is difficult to directly examine the hypothesis relating to the more theoretical issue that the dynamic sequence over time is from hallucinations to secondary delusional ideation, this hypothesis can be examined indirectly by showing that (1) the content of delusions differs as a function of whether or not hallucinations are present whereas (2) modality of hallucinations does not vary as a function of whether or not delusions are present. In other words, confirmation of hypothesis III would yield evidence that delusions ‘‘follow’’ hallucinations but not the other way around. 4. Co-occurrence of delusions and hallucinations, compared with either one in isolation, is more strongly associated with environmental exposures, such as childhood trauma, cannabis use, and an urban environment. Methods Sample Data were from the Early Developmental Stages of Psychopathology (EDSP) Study, which collected data on the prevalence, incidence, risk factors, comorbidity, and course of mental disorders in a random, representative population sample of adolescents and young adults in the general population. The baseline sample was randomly drawn, in 1994, from the respective population registry offices of Munich and its 29 counties to mirror the distribution of individuals expected to be 14–24 years of age at the time of the baseline (T0) interview in 1995. More details on the sampling, representativeness, instruments, procedures, and statistical methods of the EDSP Study sample have previously been presented.36,37 The EDSP study was approved by the Ethics Committee of the Technical University Dresden. Study Design The design of EDSP is longitudinal and prospective, consisting of a baseline (T0) and 3 follow-up surveys, cove (...truncated)