Patients with remitted schizophrenia may have a sleep-circadian phenotype distinguished by longer total sleep time, extended sleep latency, elevated wake after sleep onset, and decreased motor activity, with comparable findings in patients with bipolar disorder. The study findings, published in Schizophrenia Bulletin, demonstrated greater heterogeneity for sleep and circadian rhythm patterns in both schizophrenia and bipolar disorder when compared with controls.
Nicholas Meyer, BMBCh, MRCPsych, of the department of psychosis studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, United Kingdom, and colleagues used EMBASE, Medline, and PsycINFO to identify 30 case-control studies reporting actigraphic parameters in patients with remitted schizophrenia (n=15) or bipolar disorder (n=15), including 967 patients and 803 controls.
Compared with controls, patients with schizophrenia or bipolar disorder had significantly longer total sleep time (standardized mean difference [SMD], 1.26 and 0.46, respectively; P <.001 for both), time in bed (SMD, 1.05 and 0.65; P <.01 and P <.001), sleep latency (SMD, 0.74 and 0.24; P <.001 and P <.05), wake after sleep onset (SMD, 0.90 and 0.24; P <.05 and P <.001), and motor activity (SMD, −0.86 and −0.75; P <.001 and P <.01). Patients with bipolar disorder experienced significant reductions in sleep efficiency, which was not the case in patients with schizophrenia, although effect sizes for bipolar disorder were smaller overall.
Given the heterogeneity of the sleep-circadian disturbances found in this meta-analysis, the researchers also suggested that clinicians be aware of the sleep- or wake-promoting effects of different psychotropic medications and tailor these treatments to address an individual patient’s sleep-circadian phenotype.
Study limitations included the heterogeneity of the different studies in the analysis; the failure to account for primary sleep disorders, such as obstructive sleep apnea, nightmares, and restless leg syndrome; and the inability to account for the sedative effects of many antipsychotic medications, which may explain a significant percentage of the longer sleep duration found in schizophrenia.
The study investigators noted that “these results suggest the presence of common signatures of sleep-circadian dysfunction in schizophrenia and bipolar disorder, and advocate for the development of transdiagnostic interventions that target core difficulties, particularly with sleep initiation, maintenance, and hypersomnia.”
Meyer N, Faulkner SM, McCutcheon RA, Pillinger T, Dijk D-J, MacCabe JH. Sleep and circadian rhythm disturbance in remitted schizophrenia and bipolar disorder: a systematic review and meta-analysis [published online March 10, 2020]. Schizophr Bull. doi:10.1093/schbul/sbaa024