Objective: The neurodevelopmental model of schizophrenia includes the etiological impact of fetal brain stressors possibly connected with birth seasonality. Specification of social class of origin (SES) as a related risk factor remains unexamined as does type of schizophrenia as an outcome variable. The objective of this study was to test for an interconnection between SES, type of schizophrenia and seasonality of birth.
Methods: Patients (N=436) from a United States psychiatric hospital were separated into deficit/non-deficit presentation and bifurcated into poor/non-poor SES. Birth seasonality was assessed by months hypothetically connected with winter-related trimesters of gestation.
Results: Results showed that there is a significant difference (p=0.0411) in the monthly birth patterns of poor vs. non-poor patients and that the difference connects with the likelihood of deficit vs. non-deficit schizophrenia. Specifically, an elevated proportion of patients with deficit schizophrenia were born to impoverished women who likely conceived in January. Findings were confirmed by multiple levels of statistical assessment including log linear analysis.
Conclusion: The resultant model suggests the environmental location (lower SES) and timing (winter conception) of adult schizophrenia with poor outcome (deficit).