The effect of the environment on symptom dimensions in the first episode of psychosis: a multilevel study.
BACKGROUND
The extent to which different symptom dimensions vary according to epidemiological factors associated with categorical definitions of first-episode psychosis (FEP) is unknown. We hypothesized that positive psychotic symptoms, including paranoid delusions and depressive symptoms, would be more prominent in more urban environments.


METHODS
We collected clinical and epidemiological data on 469 people with FEP (ICD-10 F10-F33) in two centres of the Aetiology and Ethnicity in Schizophrenia and Other Psychoses (AESOP) study: Southeast London and Nottinghamshire. We used multilevel regression models to examine neighbourhood-level and between-centre differences in five symptom dimensions (reality distortion, negative symptoms, manic symptoms, depressive symptoms and disorganization) underpinning Schedules for Clinical Assessment in Neuropsychiatry (SCAN) Item Group Checklist (IGC) symptoms. Delusions of persecution and reference, along with other individual IGC symptoms, were inspected for area-level variation.


RESULTS
Reality distortion [estimated effect size (EES) 0.15, 95% confidence interval (CI) 0.06-0.24] and depressive symptoms (EES 0.21, 95% CI 0.07-0.34) were elevated in people with FEP living in more urban Southeast London but disorganized symptomatology was lower (EES -0.06, 95% CI -0.10 to -0.02), after controlling for confounders. Delusions of persecution were not associated with increased neighbourhood population density [adjusted odds ratio (aOR) 1.01, 95% CI 0.83-1.23], although an effect was observed for delusions of reference (aOR 1.41, 95% CI 1.12-1.77). Hallucinatory symptoms showed consistent elevation in more densely populated neighbourhoods (aOR 1.32, 95% CI 1.09-1.61).


CONCLUSIONS
In people experiencing FEP, elevated levels of reality distortion and depressive symptoms were observed in more urban, densely populated neighbourhoods. No clear association was observed for paranoid delusions; hallucinations were consistently associated with increased population density. These results suggest that urban environments may affect the syndromal presentation of psychotic disorders.
Department of Psychiatry, Herchel Smith Building for Brain and Mind Sciences,University of Cambridge,UK.
F J
FJ
Oher
NIHR Biomedical Research Centre, Psychosis Studies Department, Institute of Psychiatry,King's College London,UK.
A
A
Demjaha
MRC Biostatistics Unit,University of Cambridge,UK.
D
D
Jackson
NIHR Biomedical Research Centre and Section of Social Psychiatry, Health Service and Population Research Department,Institute of Psychiatry, King's College London,UK.
C
C
Morgan
NIHR Biomedical Research Centre, Psychosis Studies Department, Institute of Psychiatry,King's College London,UK.
P
P
Dazzan
Department of Psychology,University of Westminster,London,UK.
K
K
Morgan
NIHR Biomedical Research Centre, Psychosis Studies Department, Institute of Psychiatry,King's College London,UK.
J
J
Boydell
Division of Psychiatry,University of Nottingham,UK.
G A
GA
Doody
NIHR Biomedical Research Centre, Psychosis Studies Department, Institute of Psychiatry,King's College London,UK.
R M
RM
Murray
Institute of Psychology, Health and Society,University of Liverpool,UK.
R P
RP
Bentall
Department of Psychiatry, Herchel Smith Building for Brain and Mind Sciences,University of Cambridge,UK.
P B
PB
Jones
Department of Psychiatry, Herchel Smith Building for Brain and Mind Sciences,University of Cambridge,UK.
J B
JB
Kirkbride
D000328:Adult; D003702:Delusions / Q000453:epidemiology / Q000209:etiology*; D003863:Depression / Q000453:epidemiology / Q000209:etiology*; D004739:England / Q000453:epidemiology; D004777:Environment; D005260:Female; D006801:Humans; D008131:London / Q000453:epidemiology; D008297:Male; D010259:Paranoid Disorders / Q000453:epidemiology / Q000209:etiology*; D011618:Psychotic Disorders / Q000453:epidemiology / Q000209:etiology*; D012923:Social Class; D012931:Social Environment; D014505:Urban Population / Q000706:statistics & numerical data*; D055815:Young Adult