Childhood growth and future development of psychotic disorder among Helsinki high-risk children.

Background: The Helsinki High-Risk (HR) Study is a follow-up study of offspring (born between 1960 and 1964) of all females treated for schizophrenia spectrum disorders in mental hospitals in Helsinki before 1975, and controls.

Aim: To compare childhood growth among HR and control children, and to determine if any patterns in childhood growth predict later development of psychotic disorders within the HR group.

Methods: We accessed growth information from childhood health cards, which we obtained for 114 HR and 53 control offspring. The growth of HR children was compared with that of control children. Within the HR group, we investigated whether any association existed between childhood growth patterns and morbidity from psychotic disorders using logistic regression models.

Results: The HR girls were shorter than controls at birth (p=0.030), but this disparity vanished by age 7. In contrast, HR boys were only slightly shorter at birth than controls, but the height difference increased with age, being statistically significant at 10 years (p=0.020). Among HR children, the combination of being in the lowest tertile for ponderal index at birth but in the highest tertile for BMI at 7 years predicted later development of schizophrenia (OR 22.8, 95% CI 2.0, >100, p=0.040).

Conclusions: Catch-up growth increases the risk of schizophrenia among offspring of mothers with psychotic disorder. Whether this is an independent risk factor or merely a reflection of some other risk factors needs further research.