Exploring Light Therapy in Psychiatric Treatment
At first glance, the psychiatric ward in Trondheim resembles any typical unit dedicated to supporting individuals in acute mental distress. Yet, as night falls, a transformation occurs—the windows are filtered, and the lights shift to a gentle amber hue. This change aims to eliminate blue light wavelengths, which are known to disrupt the body’s internal clock. Here, doctors are investigating an intriguing theory: could the ward’s design itself serve as a therapeutic method?
Light plays a crucial role in regulating our circadian rhythms—the roughly 24-hour biological cycle that influences sleep and various bodily functions. There’s increasing evidence linking disruptions in these rhythms to issues such as depression, cardiovascular diseases, and dementia. In particular, irregular sleep-wake patterns are often seen in mental health conditions like bipolar disorder.
“There’s growing anecdotal and experimental evidence suggesting that individuals with bipolar disorder may be particularly sensitive to light,” remarked Prof Daniel Smith, a psychiatrist at the University of Edinburgh. He leads the UK Circadian Mental Health Network but wasn’t involved in this particular study. “Seasonal changes in daylight might exacerbate mood swings and lead to more manic episodes in the spring.”
He added that exposure to evening light tends to delay the body’s internal clock and suppress melatonin levels, causing individuals to sleep later—and possibly disrupt their overall quality of sleep. Poor sleep can disrupt daily routines and, for those already vulnerable, may trigger mood disturbances.
This growing awareness has sparked interest in using light as a means to stabilize circadian rhythms and, in turn, enhance mental health symptoms. However, large-scale clinical studies exploring this concept remain somewhat limited.
When the medical team in Trondheim set out to develop a new psychiatric unit, it presented a unique opportunity to put this theory to the test. They installed an innovative lighting system and automated blinds to eliminate blue wavelengths in the evening.
“Many patients dealing with significant mental health issues experience circadian disruption,” noted Håvard Kallestad, a researcher and consultant psychologist at St Olavs Hospital and the Norwegian University of Science and Technology, who led the research. “We aimed to see if changing the lighting could positively impact this.”
The ward was divided into two identical sections, sharing the same layout and staffing. The key difference lay in the evening lighting conditions. One side transitioned to blue-light-free lighting at 6 PM, with blinds and filters preventing similar light from entering the space. The other side maintained standard hospital lighting.
Previous studies involving healthy volunteers showed that staying in the ward altered melatonin levels, sleep patterns, and alertness.
Recently, the team assessed the impact of this intervention on 476 patients requiring short-term psychiatric intensive care for conditions like psychosis, mania, and severe depression. Half were placed in the blue-light-reduced ward, while the remaining half received typical lighting.
The findings, shared at a recent International Society for Bipolar Disorders meeting and published in PLOS Medicine, revealed that while the overall duration of stay was generally similar—averaging three to four days—patients in the specially lit ward exhibited greater clinical improvements and less aggressive behavior.
Kallestad remarked, “We observed additional benefits from the blue-light environment, particularly regarding the number of patients who left in a milder state of illness and the improvements witnessed during their stay.”
He emphasized that changes in lighting quality can enhance treatment outcomes, especially concerning aggressive behavior, which poses significant challenges in acute psychiatric settings. Studies suggest aggressive incidents can occur in 8% to 76% of cases, creating risks for both patients and staff.
Smith noted, “The findings related to aggression are particularly significant, as they may ease the care process for these individuals.”
Prof Derk-Jan Dijk, a sleep and circadian rhythm researcher from the University of Surrey, expressed that one of the study’s compelling aspects was the integration of the intervention within the ward itself. “Participants face virtually no burden; they aren’t required to engage with specific light therapy tools,” he observed.
He added that such methodologies could be applied more broadly by designing indoor spaces that align with human biological needs. “It demonstrates that light’s effects on the brain extend beyond just the biological clock or sleep; they also impact mood and alertness.”
Researchers are also looking into whether circadian lighting could aid individuals outside psychiatric facilities. The UK’s National Institute for Health and Care Research recently initiated a funding call for trials aiming to determine whether light therapy can help reset the internal clocks of individuals in care homes, potentially alleviating behavioral challenges in dementia patients.
Prof Anthony Gordon from NIHR’s health technology assessment program remarked that exploring the potential of light therapy to reduce anxiety, promote better sleep, and provide a cost-effective, non-drug approach to enhancing quality of life is key.
Prof Colleen McClung, a neuroscientist from the University of Pittsburgh, who recently reviewed circadian rhythms in psychiatric disorders, suggested that these strategies might become increasingly tailored. “If someone’s rhythms are delayed, for example, morning light therapy could be effective. Conversely, for individuals with advanced rhythms, afternoon or evening light exposure might be beneficial.”
Wearable technology that tracks sleep and activity could offer insights into these personal differences and guide treatment plans.
