Out of the blue? How the colour of light could be used to treat mental illness

"Light is the main signal regulating the body's circadian rhythm the roughly 24-hour biological clock that governs sleep and many other bodily processes. Mounting evidence links circadian disruption to conditions including depression, cardiovascular disease and dementia, and disturbed sleep-wake cycles are a long-recognised feature of mental illness, particularly bipolar disorder."

"Increasingly, both anecdotal and experimental evidence suggests that bipolar people are quite sensitive to light, which can be unhelpful for them in terms of seasonal changes in mood and more manic relapses with the lengthening days in springtime. The general idea is that evening light exposure, in particular, delays the phase of the clock, suppresses melatonin, and because of that, people go to sleep later and probably don't sleep as well."

"Poor sleep can then destabilise daily patterns of rest and activity, which in vulnerable individuals may trigger mood episodes. Because of this, there is growing interest in using light to stabilise people's body rhythms and, in turn, improve their symptoms although relatively few large clinical studies have tested the idea."

A psychiatric ward in Trondheim is testing whether environmental design, specifically dynamic lighting systems, can serve as a treatment for mental illness. Light is the primary regulator of circadian rhythm, the body's 24-hour biological clock controlling sleep and other processes. Circadian disruption is linked to depression, cardiovascular disease, and dementia. Mental illness, particularly bipolar disorder, features disturbed sleep-wake cycles. Evening light exposure delays the circadian clock phase, suppresses melatonin, and causes later sleep onset and poor sleep quality. Poor sleep destabilizes daily rest-activity patterns, potentially triggering mood episodes in vulnerable individuals. The Trondheim unit installed dynamic lighting and automated blinds that remove blue wavelengths during evening hours to stabilize patients' body rhythms and improve psychiatric symptoms.

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