The study of high-risk groups and the development of schizophrenia.
To investigate further schizotypy, measured by the Structured Interview for Schizotypy (SIS), and to examine relationships between schizotypal components, psychotic symptoms on the Present State Examination (PSE) and subsequent schizophrenia.
The SIS and PSE were administered on entry. Schizophrenia onsets were recorded during follow-up.
The SIS yielded four principal components labelled social withdrawal, psychotic symptoms, socio-emotional dysfunction and odd behaviour. On entry, these differentiated between controls, subjects at risk for schizophrenia with and without symptoms and patients with schizophrenia. Seven of 78 subjects at risk developed schizophrenia within 39 months. This was best predicted by combining the four SIS components.
Schizotypy is heterogeneous and may become psychosis, particularly if several of its components are present. As psychosis develops, odd behaviour gives way to psychotic symptoms and social function deteriorates.