A recent study found that symptoms of psychosis, schizotypy, and normal personality reflect the same underlying dimensions. Specifically, (low) extraversion, negative schizotypy, and negative symptoms form one spectrum, whereas psychoticism, positive schizotypy, and positive and disorganized symptoms form another. This framework helps to understand the heterogeneity of psychosis and comorbidity patterns found in psychotic disorders and also underscores the importance of traits to understanding these disorders. Researchers examined the joint factor structure of normal personality, schizotypy, and schizophrenia symptoms in people with psychotic disorders (n=288) and never-psychotic adults (n= 57) in the Suffolk County Mental Health Project. Highlights of the study included:
- Researchers first evaluated the structure of schizotypal (positive schizotypy, negative schizotypy, and mistrust) and normal traits.
- In both the psychotic-disorder and never-psychotic groups, the best-fitting model had 5 factors: neuroticism, extraversion, conscientiousness, agreeableness, and psychoticism.
- The schizotypy traits were placed on different dimensions: negative schizotypy went on (low) extraversion, whereas positive schizotypy and mistrust went on psychoticism.
- Next, they added symptoms to the model.
- Reality distortion (hallucinations and delusions) and disorganization symptoms were placed on psychoticism, and negative symptoms were placed on extraversion.
Cicero DC, Jonas KG, Li K, Perlman G, Kotov R. Common taxonomy of traits and symptoms: Linking schizophrenia symptoms, schizotypy, and normal personality. [Published online ahead of print February 9, 2019]. Schizophr Bull. doi:10.1093/schbul/sbz005.