Table 3.

Prenatal stress and schizophrenia.

Authors and year	Location	Type of study	N	Diagnosis	Finding
Huttunen and Niskanen (1978)	Helsinki, Finland	Retrospective population-based cohort study	167 cases	Psychiatric disorders including: schizophrenic psychoses, manic-depressive psychoses, minor depressive and neurotic disorders, alcoholism and/or personality disorders, asocial behavior, childhood behavior disorders determined through review of psychiatric registry	Loss of father during months 3–5 and 9–10 of pregnancy associated with increased risk of psychiatric disorders in offspring
Myhrman et al. (1996)	Northern Finland	Birth cohort study	76 cases	DSM-III-R diagnosis of schizophrenia determined through psychiatric record review	Unwanted pregnancy was associated with a greater than two-fold statistically significant increase in schizophrenia risk in the offspring
van Os and Selten (1998)	Netherlands	Retrospective birth cohort study	1899 cases	Diagnosis of schizophrenia identified through National Psychiatric Case Register	Prenatal exposure to the May 1940 five-day invasion of the Netherlands by the German forces was associated with increased incidence of schizophrenia, especially in those exposed in the 1st trimester (1.28-fold increase in risk) and in men (1.35-fold increase in risk)
Selten et al. (1999)	Netherlands	Retrospective epidemiological study	118 cases	ICD categories schizophrenic disorder, paranoid state and other non-organic, non-affective psychosis identified through Dutch Psychiatric Register	Prenatal exposure to 1953 Dutch Flood Disaster was associated with 1.8-fold increase in risk of non-affective psychosis, but the association was not significant
Herman et al. (2006)	Alameda County, California	Prospectively collected birth cohort analysis	71 cases	Schizophrenia Spectrum Disorders (SSDs), including schizophrenia, schizoaffective disorder, delusional disorder, psychotic disorder NOS, and schizotypal personality disorder, diagnosed through psychiatric record review and diagnostic interview (Diagnostic Interview for Genetic Studies)	Unwantedness of pregnancy was associated with a 1.75-fold increase in risk for adult schizophrenia spectrum disorders but the effect was non-significant
Khashan et al. (2008)	Denmark	National population-based study	7331 cases	ICD-8 and ICD-10 diagnoses of schizophrenia and related disorders determined from Danish Psychiatric Central Register	Offspring whose mothers were exposed to death of a relative, or who had a relative diagnosed with cancer, acute myocardial infarction, or stroke syndrome during the 1st trimester had a 1.67-fold increased risk of developing schizophrenia and related disorders