The role of knowledge and motivation in symptom identification accuracy among schizophrenic patients: Application of signal detection theory

OBJECTIVE: Many people with schizophrenia have poor awareness of their symptoms, a problem that may result from lack of knowledge about their illness and/or unwillingness to acknowledge it. The present study assessed the joint influence of lack of knowledge and motivated denial in schizophrenic patients' low symptom awareness. METHOD: Schizophrenic patients (N = 85) and normal control participants (N = 35) identified psychotic symptoms and general stress symptoms in a symptom checklist. The signal detection theory was applied to assess levels of sensitivity (which would be knowledge-mediated) and judgment biases (which would probably be motivated). RESULTS: Compared with normal control participants, schizophrenic patients had lower sensitivity and greater aversion to classify a symptom as a psychotic symptom. CONCLUSIONS: These findings suggest that both lack of knowledge and motivated denial are involved in schizophrenic patients' low symptom awareness.