Sleep in patients with schizophrenia

Numerous electrophysiological and neuroimaging studies have reported neurophysiological and cognitive deficits in schizophrenia patients during wakefulness. However, these findings have been inconsistently replicated across different groups of patients, thus complicating the identification of underlying neuronal defects. Sleep minimizes possible waking-related confounds, including decreased motivation and presence of active symptoms. Additionally, the two main sleep rhythms, slow waves and spindles, reflect the intrinsic activity of corticothalamic circuits and are associated with cognitive activities, including learning and memory, occurring during wakefulness. In this review I will present the most relevant sleep findings in schizophrenia, with particular emphasis on several recent studies that have consistently reported sleep spindle deficits in patients with schizophrenia. I will then elaborate on how these findings may contribute to a better understanding of the neurobiology of schizophrenia as well as to the development of novel pharmacological and non-pharmacological interventions to ameliorate the symptoms and cognitive impairments of schizophrenia patients.