Geographical variation in rates of common mental disorders in Britain: prospective cohort study.
BACKGROUND
There is little geographical variation in the prevalence of the common mental disorders. However, there is little longitudinal research.


OBJECTIVE
To estimate variance in rates of common mental disorders at individual, household and electoral ward levels prospectively.


METHODS
A 12-month cohort study of 7659 adults aged 16-74 years in 4338 private households, in 626 electoral wards. Data were collected as part of the British Household Panel Survey. Common mental disorders were assessed using the 12-item General Health Questionnaire (GHQ). Ward-level socio-economic deprivation was measured using the Carstairs index.


RESULTS
Less than 1% of total variance, in onset and maintenance of common mental disorders and change in GHQ score between waves, occurred at ward level. However, 12% of variance, which is a statistically significant difference, was found at household level (a much smaller geographical unit) and this difference remained after further analyses.


CONCLUSIONS
Ward level socio-economic deprivation does not influence the onset and maintenance of common mental disorders in Britain but local factors at the household level do. Reasons for this remain unclear.
Division of Health in the Community, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK. s.weich@warwick.ac.uk
Scott
S
Weich
Liz
L
Twigg
Glyn
G
Lewis
Kelvyn
K
Jones
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology* / Q000209:etiology; D008875:Middle Aged; D011204:Poverty Areas; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D012111:Residence Characteristics; D012307:Risk Factors; D012959:Socioeconomic Factors; D006113:United Kingdom / Q000453:epidemiology