Association between developmental milestones and age of schizophrenia onset: results from the Northern Finland birth cohort 1966

We investigated relationships between early developmental milestones, schizophrenia incidence and variability in its age at onset. We hypothesised that the period of risk for schizophrenia would be longer for those with later development. The Northern Finland Birth Cohort 1966 was followed until 47 years of age, and those members diagnosed with schizophrenia or any other non-affective psychoses identified. Latent profile analysis was used to classify people into homogenous classes with respect to developmental milestones, and subsequently survival analysis explored relationship between classes and age of schizophrenia onset. Results suggest that 4-classes (early, regular, late, and extra late developers) can be identified, but due to few cases in one class (n=93,