Sleep and circadian rhythm disruption in schizophrenia
Wulff K., Dijk D-J., Middleton B., Foster RG., Joyce EM.
<jats:sec><jats:title>Background</jats:title><jats:p>Sleep disturbances comparable with insomnia occur in up to 80% of people with schizophrenia, but very little is known about the contribution of circadian coordination to these prevalent disruptions.</jats:p></jats:sec><jats:sec><jats:title>Aims</jats:title><jats:p>A systematic exploration of circadian time patterns in individuals with schizophrenia with recurrent sleep disruption.</jats:p></jats:sec><jats:sec><jats:title>Method</jats:title><jats:p>We examined the relationship between sleep–wake activity, recorded actigraphically over 6 weeks, along with ambient light exposure and simultaneous circadian clock timing, by collecting weekly 48 h profiles of a urinary metabolite of melatonin in 20 out-patients with schizophrenia and 21 healthy control individuals matched for age, gender and being unemployed.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Significant sleep/circadian disruption occurred in all the participants with schizophrenia. Half these individuals showed severe circadian misalignment ranging from phase-advance/delay to non-24 h periods in sleep–wake and melatonin cycles, and the other half showed patterns from excessive sleep to highly irregular and fragmented sleep epochs but with normally timed melatonin production.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>Severe circadian sleep/wake disruptions exist despite stability in mood, mental state and newer antipsychotic treatment. They cannot be explained by the individuals' level of everyday function.</jats:p></jats:sec>