To what extent do neurobiological sleep-waking processes support psychoanalysis?

Schizotypy unfolding into the night? Schizotypal traits and daytime psychotic-like experiences predict negative and salient dreams

Symptoms of insomnia and frequent nightmares are prevalent in psychotic disorders, and are associated with psychotic-like experiences (PLEs) in the non-clinical population. Whereas the role of impaired sleep in psychosis was extensively examined by longitudinal and interventional approaches, studies on the association between psychosis and dream quality are scarce, and mainly cross-sectional. We conducted a three-week long prospective study in a group of healthy adults (N = 55), assessed schizotypal traits, daily PLEs, and the emotional quality of dreams recalled in the morning (N = 490). We extracted the latent factors of schizotypal traits and dream emotions, and examined the predictive value of trait-and state-like variables on day-to-day reports of PLEs and dream quality. PLEs reported in the evening predicted emotionally more negative and salient dream reports the following morning. On the other hand, the quality of dreams were not predictive of PLEs reported later during the day. Schizotypal personality traits were differentially associated with dream quality: Introvertive Anhedonia, Cognitive Disorganization, and General-Disorganized schizotypy were linked to more negative dream valence, whereas Unusual Experiences were associated with more salient dreams. Our findings highlight the relevance of the multidimensional nature of schizotypal traits, the role of different facets of schizotypy in daytime and nocturnal mental experiences, and the day-to-day associations between PLEs and dream affect. GENERAL SCIENTIFIC SUMMARIES (GSS): The aim of the study was to examine the temporal associations between psychotic-like experiences and dream emotions, taking into account the trait factors of schizotypy. Psychotic-like experiences during the evening hours predicted reporting more negative and salient dreams the following morning, and schizotypal personality traits were differentially associated with the dimensions of dream emotions.

The Functional Role of Dreaming in Emotional Processes

Dream experience (DE) represents a fascinating condition linked to emotional processes and the human inner world. Although the overlap between REM sleep and dreaming has been overcome, several studies point out that emotional and perceptually vivid contents are more frequent when reported upon awakenings from this sleep stage. Actually, it is well-known that REM sleep plays a pivotal role in the processing of salient and emotional waking-life experiences, strongly contributing to the emotional memory consolidation. In this vein, we highlighted that, to some extent, neuroimaging studies showed that the processes that regulate dreaming and emotional salience in sleep mentation share similar neural substrates of those controlling emotions during wakefulness. Furthermore, the research on EEG correlates of the presence/absence of DE and the results on EEG pattern related to the incorporated memories converged to assign a crucial role of REM theta oscillations in emotional re-processing. In particular, the theta activity is involved in memory processes during REM sleep as well as during the waking state, in line with the continuity hypothesis. Also, the gamma activity seems to be related to emotional processes and dream recall as well as to lucid dreams. Interestingly, similar EEG correlates of DE have been found in clinical samples when nightmares or dreams occur. Research on clinical samples revealed that promoting the rehearsal of frightening contents aimed to change them is a promising method to treat nightmares, and that lucid dreams are associated with an attenuation of nightmares. In this view, DE can defuse emotional traumatic memories when the emotional regulation and the fear extinction mechanisms are compromised by traumatic and frightening events. Finally, dreams could represent a sort of simulation of reality, providing the possibility to create a new scenario with emotional mastery elements to cope with dysphoric items included in nightmares. In addition, it could be hypothesized that the insertion of bizarre items besides traumatic memories might be functional to "impoverish" the negative charge of the experiences.

The involvement of noradrenaline in rapid eye movement sleep mentation

Noradrenaline, one of the main brain monoamines, has powerful central influences on forebrain neurobiological processes which support the mental activities occurring during the sleep-waking cycle. Noradrenergic neurons are activated during waking, decrease their firing rate during slow wave sleep, and become silent during rapid eye movement (REM) sleep. Although a low level of noradrenaline is still maintained during REM sleep because of diffuse extrasynaptic release without rapid withdrawal, the decrease observed during REM sleep contributes to the mentation disturbances that occur during dreaming, which principally resemble symptoms of schizophrenia but seemingly also of attention deficit hyperactivity disorder.