Social adversity in childhood and the risk of developing psychosis: a national cohort study.
OBJECTIVE
There is conflicting evidence concerning the association of social childhood factors and subsequent psychosis. Previous studies have had inadequate designs. The aim of the present study was to describe a broad range of social factors during childhood and the risk of developing psychosis later in life in a national cohort.


METHODS
The study population consisted of all children born in Sweden in 1963-1983-2.1 million persons-in family households participating in the national census of 1970, 1980, 1985, or 1990. Hazard ratios were estimated for five different indicators of socioeconomic position (living in rented apartments, low socioeconomic status, single-parent households, unemployment, and households receiving social welfare benefits) from hospital admissions for schizophrenia and other psychoses during 1987-2002.


RESULTS
Increased age- and sex-adjusted hazard ratios for schizophrenia and other psychoses were found for all childhood socioeconomic indicators, ranking from lowest to highest hazard ratio: rented apartments, low socioeconomic status, single-parent households, unemployment, and households receiving social welfare benefits. Hazard ratios increased with an increasing number of adverse social factors present. Those with four measures of adversity had a 2.7-fold higher risk of schizophrenia than those with none.


CONCLUSIONS
The results indicate that social adversity in childhood and fetal life is independently associated with the risk of developing schizophrenia and other psychoses later in life. The risks increased with an increasing number of exposures, suggesting a dose-response relationship.
Wicks
Susanne
S
Unit of Epidemiology, Stockholm Centre for Public Health, Norrbacka, Floor 5, 171 76 Stockholm, Sweden. susanne.wicks@sll.se
Hjern
Anders
A
Gunnell
David
D
Lewis
Glyn
G
Dalman
Christina
C
D000328:Adult; D000367:Age Factors; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011618:Psychotic Disorders / Q000453:epidemiology* / Q000209:etiology / Q000523:psychology; D012111:Residence Characteristics; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology / Q000209:etiology; D012565:Schizophrenic Psychology; D020954:Single-Parent Family; D012923:Social Class; D012924:Social Conditions / Q000145:classification*; D012946:Social Welfare; D012959:Socioeconomic Factors; D013548:Sweden / Q000453:epidemiology; D014478:Unemployment