Abstract
Cognitive deficits are a core feature of schizophrenia and appear with increased severity in early-onset schizophrenia (EOS). EOS is defined as onset of symptoms before 18 years of age. Affected youths often experience increased symptom severity compared to those with later onset, in addition to a more severe clinical course and outcome. The interaction between biological and psychosocial factors seems to determine the incidence and expression of schizophrenia, but the way in which they interact is uncertain. Evidence indicates that the disease reflects underlying deviations in early brain development, and that fetal exposure to obstetric complications (OC) is a risk factor for developing the illness and may also affect cognitive deficits in schizophrenia.
Research questions that remain unexamined are whether cognitive deficits in EOS may derive from exposure to OC, and if so, how the individual OC affect different areas of cognition. Also, there is still uncertainty about the longitudinal cognitive course in EOS; some suggest neurodegeneration after illness onset, while others claim a stable cognitive course after onset. Another question is the extent to which the cognitive course in EOS is influenced by clinical characteristics during the early illness period, such as psychotic and general symptoms and duration of untreated psychosis.