Non-psychotic psychiatric disorder and subsequent risk of schizophrenia. Cohort study.
BACKGROUND
Those with schizophrenia often give a history of premorbid non-psychotic psychiatric disorder.


OBJECTIVE
To investigate the association between non-psychotic psychiatric disorders and the later development of schizophrenia.


METHODS
Men aged 18 or 19 years, conscripted to the Swedish army in 1970 (n=50 054) were linked to the Swedish National Psychiatric Case Register.


RESULTS
There was an increased risk of schizophrenia in those with ICD-8 diagnoses of neurosis (OR=4.6,95% Cl 3.2-6.9), personality disorder (OR=8.2, 95% Cl 5.4-12.3), alcohol abuse (OR=5.5, 95% Cl 1.7-17.5) or substance abuse (OR=14.0, 95% Cl 7.8-25.0) at age 18. Of those who developed schizophrenia, 38% (95% Cl 32-45) received a diagnosis of non-psychotic psychiatric disorder at age 18. Only those with personality disorder had a significantly increased risk of schizophrenia (OR=2.4, 95% Cl 1.1-5.2) with onset after age 23.


CONCLUSIONS
Personality factors could represent an underlying vulnerability to schizophrenia. Other diagnoses occurring before schizophrenia may reflect a prodromal phase of the illness.
Lewis
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Division of Psychological Medicine, University of Wales College of Medicine, Cardiff, UK. wpcghl@cardiff.ac.uk
David
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AS
Malmberg
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A
Allebeck
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P
D000293:Adolescent; D000328:Adult; D000437:Alcoholism / Q000150:complications; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009497:Neurotic Disorders / Q000150:complications; D010554:Personality Disorders / Q000150:complications*; D012042:Registries; D012307:Risk Factors; D012559:Schizophrenia / Q000209:etiology*; D012565:Schizophrenic Psychology; D019966:Substance-Related Disorders / Q000150:complications