Nightmares, dreams, and schizotypy.

The theory that psychosis and dreaming share some common underlying mechanism finds support in the observation that chronic nightmare sufferers are at increased risk for psychopathology. We examined this connection in a large general population sample, administering a battery of psychosis proneness and other personality scales, together with a nightmare distress scale; participants also answered a single question on pleasurable mood associated with dreaming. In addition, they completed the Bem Sex Role Inventory, to reinvestigate previously observed gender differences in nightmare susceptibility. It was found that, among the psychosis proneness scales, the best predictor of nightmare distress was STA, a mostly cognitive measure of schizotypy; this was true even after allowing for a strong influence in the data of general neuroticism. Other aspects of psychosis proneness--e.g. anhedonia--were unrelated to nightmares. However, sex and sex role differences did make a significant contribution, self-confessed feminine females and masculine males reporting, respectively, the highest and lowest nightmare distress. For schizotypy it was further shown that relationships were not confined to the nightmare experience; high (STA) schizotypes also significantly more often reported enjoyable dreaming. It was concluded that a unifying theme explaining the data is the schizotype's greater imaginativeness, which can have both positive and negative expression in sleep and consciousness.