First night effect in different forms of schizophrenia (Pilot investigation)

Polysomnograhpy was performed during two consecutive nights in 20 schizophrenic patients and in 10 healthy controls. »First night effect« (the increase of REM sleep latency on the first night by at least 30 minutes in comparison to the second night) was present in 35% of schizophrenic patients and in 80% of healthy subjects. The increase of REM sleep latency in schizophrenic patients was accompanied by the decreased sleep efficiency in the same night as well as by the increased number of awakenings in comparison to healthy subjects. The mean age of subjects and the mean data of positive symptoms were higher in schizophrenic patients with the »first night effect« than in patients without »first night effect«. Search activity concept is used for the explanation of these data.