Age at onset and outcome in schizophrenia are related to the degree of familial loading.

Abstract

Recent research suggests that high familial loading is associated with early onset of schizophrenia. Results concerning outcome have been controversial. We assessed the relationship between familial loading, age at onset and outcome in all Finnish patients with schizophrenia born between 1950 and 1969. Patients and their first-degree relatives were identified using nationwide registers. Familial loading scores were calculated for schizophrenia and for combined psychotic disorders, and patients were accordingly classified into three groups: high (n = 761), intermediate (n = 14,247), and low familial loading (n = 725). Linear mixed models and the Cox proportional hazard model were used in the analyses. Onset was earliest, hospitalisation longest and risk of retirement in receipt of a disability pension highest in the group with high familial loading, with opposite extremes found in the group with low familial loading. High familial loading for schizophrenia is associated with early onset and poor outcome of schizophrenia.