TESTING LIDDLE 3-SYNDROME MODEL IN FAMILIES WITH SCHIZOPHRENIA

While the symptoms of schizophrenia can be grouped into positive and n egative syndromes, increasing evidence suggests that three clusters of symptoms are present. Liddle (1987a) described a three-syndrome model comprised of reality distortion, psychomotor poverty and disorganizat ion symptom clusters. This model was assessed in the present study usi ng a sample of 72 members of five families segregating schizophrenia. A wide range of psychopathology was present across a spectrum of diagn oses. Data on symptoms used in Liddle's model were derived from the Po sitive and Negative Syndrome Scale (PANSS) and a mental status examina tion. Factor analysis of the data indicated the presence of three clus ters of symptoms. The psychomotor poverty or negative symptom cluster was confirmed in the familial sample. However, the other two factors d iffered somewhat from the Liddle model. Hallucinations, delusions, dis organized thinking and inappropriate affect formed one factor; suspici ousness and stereotyped thinking formed the other. These three symptom clusters may be comparable to the catatonic, hebephrenic and paranoid classical subtypes of schizophrenia. The implications of Liddle's mod el for genetic studies of schizophrenia require further investigation.