• birth characteristics;
  • hospitalization;
  • mental illness

Objective:  Preterm birth and restricted foetal growth are related to symptoms of psychiatric disorder. Our aim was therefore to investigate possible relations between being born preterm and/or small for gestational age (SGA) and later psychiatric hospitalization.

Method:  A population-based registry study of psychiatric hospitalization of in total 155 994 boys and 148 281 girls born in Sweden in 1973–1975.

Results:  The risk of hospitalization for all mental disorders was increased for preterm SGA boys (OR 2.19, 95% CI 1.49–3.21); at-term SGA boys (OR 1.55, 95% CI 1.34–1.79); at-term SGA girls (OR 1.31, 95% CI 1.15–1.50). At-term SGA boys and girls suffered increased risk of anxiety and adjustment disorders (OR 1.70, 95% CI 1.18–2.45 and OR 1.49, 95% CI 1.14–1.94). Preterm SGA boys were at risk of personality disorders (OR 3.30, 95% CI 1.16–9.41) and psychotic disorders (OR 4.36, 95% CI 1.85–10.30).

Conclusion:  The results show a relationship between being born SGA and later psychiatric hospitalization, where preterm birth and male gender seem to increase the risk.