Dream research in schizophrenia: methodological issues and a dimensional approach

Dreaming in patients with schizophrenia was and is of particular interest to researchers and clinicians due to the phenomenological similarities between the dreaming state and schizophrenic daytime symptomatology such as bizarre thoughts or hallucinations. Extensive literature reviews have shown that dream studies in the field of psychopathology often do not fulfill common scientific criteria. The present paper focuses on the methodological issues like sampling methods, the dream collection method, and dream content analysis that are crucial with regard to the validity of the findings. It is also suggested that the so-called dimensional approach (linking severity of daytime symptoms directly to specific dream characteristics) will be very helpful for identifying which psychopathological symptoms of schizophrenia are most closely linked to dream content.