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Updated: May 26, 2026

Through-the-Wall Blood Sampling Method to Minimize Sleep Disruption in Clinical Settings
Published on: June 13, 2025
Sleep and circadian rhythm disruption in schizophrenia
Katharina Wulff1, Derk-Jan Dijk, Benita Middleton
1Nuffield Laboratory of Ophthalmology, University of Oxford, The John Radcliffe Hospital, Headley Way, Oxford, UK.
Background:
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.
Aims:
A systematic exploration of circadian time patterns in individuals with schizophrenia with recurrent sleep disruption.
Method:
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.
Results:
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.
Conclusions:
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.
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