Examining the content of psychotic symptoms may be relevant for understanding symptom development particularly in those in the very early stages of psychosis. The Content of Attenuated Positive Symptoms codebook was developed as a means to overcome methodological issues in the current literature. Three separate samples at clinical high risk of psychosis were used to develop, modify and finalize the codebook. The inter-rater reliability was moderate to excellent. Specific content items were consistently endorsed across samples. This codebook offers a reliable way to assess content in the clinical high-risk population.

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