Increased sensitivity of the circadian system to light in delayed sleep–wake phase disorder

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Patients with delayed sleep–wake phase disorder (DSWPD) exhibit delayed sleep–wake behaviour relative to desired bedtime, often leading to chronic sleep restriction and daytime dysfunction. The majority of DSWPD patients also display delayed circadian timing in the melatonin rhythm. Hypersensitivity of the circadian system to phase-delaying light is a plausible physiological basis for DSWPD vulnerability. We compared the phase shifting response to a 6.5 h light exposure (~150 lux) between male patients with diagnosed DSWPD (n = 10; aged 20.8 ± 2.3 years) and male healthy controls (n = 11; aged 22.4 ± 3.3 years). Salivary dim light melatonin onset (DLMO) was measured under controlled conditions in dim light (<3 lux) before and after light exposure. Correcting for the circadian time of the light exposure, DSWPD patients exhibited 31.5% greater phase delay shifts than healthy controls. In both groups, a later initial melatonin phase was associated with a greater magnitude phase shift, indicating that increased circadian sensitivity to light may be a factor that contributes to delayed phase, even in non-clinical groups. DSWPD patients also had reduced pupil size following the light exposure, and showed a trend towards increased melatonin suppression during light exposure. These findings indicate that, for patients with DSWPD, assessment of light sensitivity may be an important factor that can inform behavioural therapy, including minimization of exposure to phase-delaying night-time light.

Original languageEnglish
Pages (from-to)6249-6261
Number of pages13
JournalThe Journal of Physiology
Volume596
Issue number24
DOIs
Publication statusPublished - 15 Dec 2018

Cite this

@article{73bdf6921c5f456588c05cc0852c96fd,
title = "Increased sensitivity of the circadian system to light in delayed sleep–wake phase disorder",
abstract = "Patients with delayed sleep–wake phase disorder (DSWPD) exhibit delayed sleep–wake behaviour relative to desired bedtime, often leading to chronic sleep restriction and daytime dysfunction. The majority of DSWPD patients also display delayed circadian timing in the melatonin rhythm. Hypersensitivity of the circadian system to phase-delaying light is a plausible physiological basis for DSWPD vulnerability. We compared the phase shifting response to a 6.5 h light exposure (~150 lux) between male patients with diagnosed DSWPD (n = 10; aged 20.8 ± 2.3 years) and male healthy controls (n = 11; aged 22.4 ± 3.3 years). Salivary dim light melatonin onset (DLMO) was measured under controlled conditions in dim light (<3 lux) before and after light exposure. Correcting for the circadian time of the light exposure, DSWPD patients exhibited 31.5{\%} greater phase delay shifts than healthy controls. In both groups, a later initial melatonin phase was associated with a greater magnitude phase shift, indicating that increased circadian sensitivity to light may be a factor that contributes to delayed phase, even in non-clinical groups. DSWPD patients also had reduced pupil size following the light exposure, and showed a trend towards increased melatonin suppression during light exposure. These findings indicate that, for patients with DSWPD, assessment of light sensitivity may be an important factor that can inform behavioural therapy, including minimization of exposure to phase-delaying night-time light.",
author = "Watson, {Lauren A.} and Phillips, {Andrew J. K.} and Hosken, {Ihaia T.} and McGlashan, {Elise M.} and Clare Anderson and Lack, {Leon C.} and Lockley, {Steven W.} and Rajaratnam, {Shantha M. W.} and Cain, {Sean W.}",
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doi = "10.1113/JP275917",
language = "English",
volume = "596",
pages = "6249--6261",
journal = "The Journal of Physiology",
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Increased sensitivity of the circadian system to light in delayed sleep–wake phase disorder. / Watson, Lauren A.; Phillips, Andrew J. K.; Hosken, Ihaia T.; McGlashan, Elise M.; Anderson, Clare; Lack, Leon C.; Lockley, Steven W.; Rajaratnam, Shantha M. W.; Cain, Sean W.

In: The Journal of Physiology, Vol. 596, No. 24, 15.12.2018, p. 6249-6261.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Increased sensitivity of the circadian system to light in delayed sleep–wake phase disorder

AU - Watson, Lauren A.

AU - Phillips, Andrew J. K.

AU - Hosken, Ihaia T.

AU - McGlashan, Elise M.

AU - Anderson, Clare

AU - Lack, Leon C.

AU - Lockley, Steven W.

AU - Rajaratnam, Shantha M. W.

AU - Cain, Sean W.

PY - 2018/12/15

Y1 - 2018/12/15

N2 - Patients with delayed sleep–wake phase disorder (DSWPD) exhibit delayed sleep–wake behaviour relative to desired bedtime, often leading to chronic sleep restriction and daytime dysfunction. The majority of DSWPD patients also display delayed circadian timing in the melatonin rhythm. Hypersensitivity of the circadian system to phase-delaying light is a plausible physiological basis for DSWPD vulnerability. We compared the phase shifting response to a 6.5 h light exposure (~150 lux) between male patients with diagnosed DSWPD (n = 10; aged 20.8 ± 2.3 years) and male healthy controls (n = 11; aged 22.4 ± 3.3 years). Salivary dim light melatonin onset (DLMO) was measured under controlled conditions in dim light (<3 lux) before and after light exposure. Correcting for the circadian time of the light exposure, DSWPD patients exhibited 31.5% greater phase delay shifts than healthy controls. In both groups, a later initial melatonin phase was associated with a greater magnitude phase shift, indicating that increased circadian sensitivity to light may be a factor that contributes to delayed phase, even in non-clinical groups. DSWPD patients also had reduced pupil size following the light exposure, and showed a trend towards increased melatonin suppression during light exposure. These findings indicate that, for patients with DSWPD, assessment of light sensitivity may be an important factor that can inform behavioural therapy, including minimization of exposure to phase-delaying night-time light.

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JF - The Journal of Physiology

SN - 0022-3751

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ER -