Background: Substantial variability in age at onset of illness and course of illness exists between patients with schizophrenia. Recent studies suggest that age at illness onset may be useful in defining biologically and clinically distinct subgroups of patients.
Methods: Two hundred and ten males with schizophrenia were classified as early-onset or adult-onset according to their age at first hospitalization. Birth history, clinical functioning and treatment response was assessed in a subgroup of patients. Brain anatomy was assessed from CT scans in all patients and in 32 non-psychiatric control subjects.
Results: Patients with an early-onset were likely to have a history of obstetric complications, a poor response to neuroleptic treatment, and showed no relationship between ventricle size and duration of illness. Adult-onset patients were less likely to have obstetric complications, more likely to respond to treatment in the first years of illness, and showed an association between brain structure and duration of illness.
Conclusions: The distinction between early- and adult-onset patients may have important aetiological and treatment implications.