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 = 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 = 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.

Background The base rate of transition from subthreshold psychotic experiences (the exposure) to clinical psychotic disorder (the outcome) in unselected, representative and non-help-seeking population-based samples is unknown. Method A systematic review and meta-analysis was conducted of representative, longitudinal population-based cohorts with baseline assessment of subthreshold psychotic experiences and follow-up assessment of psychotic and non-psychotic clinical outcomes. Results Six cohorts were identified with a 3–24-year follow-up of baseline subthreshold self-reported psychotic experiences. The yearly risk of conversion to a clinical psychotic outcome in exposed individuals (0.56%) was 3.5 times higher than for individuals without psychotic experiences (0.16%) and there was meta-analytic evidence of dose–response with severity/persistence of psychotic experiences. Individual studies also suggest a role for motivational impairment and social dysfunction. The evidence for conversion to non-psychotic outcome was weaker, although findings were similar in direction. Conclusions Subthreshold self-reported psychotic experiences in epidemiological non-help-seeking samples index psychometric risk for psychotic disorder, with strong modifier effects of severity/persistence. These data can serve as the population reference for selected and variable samples of help-seeking individuals at ultra-high risk, for whom much higher transition rates have been indicated.

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 = 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 = 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.

Background The base rate of transition from subthreshold psychotic experiences (the exposure) to clinical psychotic disorder (the outcome) in unselected, representative and non-help-seeking population-based samples is unknown. Method A systematic review and meta-analysis was conducted of representative, longitudinal population-based cohorts with baseline assessment of subthreshold psychotic experiences and follow-up assessment of psychotic and non-psychotic clinical outcomes. Results Six cohorts were identified with a 3–24-year follow-up of baseline subthreshold self-reported psychotic experiences. The yearly risk of conversion to a clinical psychotic outcome in exposed individuals (0.56%) was 3.5 times higher than for individuals without psychotic experiences (0.16%) and there was meta-analytic evidence of dose–response with severity/persistence of psychotic experiences. Individual studies also suggest a role for motivational impairment and social dysfunction. The evidence for conversion to non-psychotic outcome was weaker, although findings were similar in direction. Conclusions Subthreshold self-reported psychotic experiences in epidemiological non-help-seeking samples index psychometric risk for psychotic disorder, with strong modifier effects of severity/persistence. These data can serve as the population reference for selected and variable samples of help-seeking individuals at ultra-high risk, for whom much higher transition rates have been indicated.