A Scotland-wide study is to investigate how light and the body’s internal clock influence symptoms in people with bipolar disorder.
People diagnosed with the condition are being invited to take part in research that will test their sensitivity to light at night.
The study will help scientists understand if lithium – the most effective treatment for bipolar disorder – stabilises the condition by altering patients’ response to light. Despite being used for more than 70 years, precisely how lithium acts to improve patient health is unknown, experts say.
Body clock
So-called circadian rhythms are part of the 24-hour internal clock that helps to synchronise bodily functions and behaviour to regular cycles of night and day. Light in the morning can help people feel awake, while darkness in the evening signals the brain to make the sleep hormone, melatonin.
Changes to the body’s internal clock have long been thought to play a role in bipolar disorder.
Among those with the condition, hospital admissions related to depression peak in autumn and winter, while admissions for mania – periods of high energy and excited behaviour – are highest in spring and summer.
Light sensitivity
The University of Edinburgh-led project, named after the Greek sun god Helios, will explore if people with bipolar disorder are hypersensitive to excess light in the evening – disrupting their body clock and increasing the risk of manic relapse.
More than 100 volunteers from across Scotland will take part in a sleep study, with participants being exposed to a bright light during the night. Melatonin levels will be tested to see if they are reduced in those with bipolar disorder, compared with those who have no history of mental illness.
Scientists will also investigate whether treatment with lithium helps to prevent hypersensitivity to light and normalise melatonin production in those with bipolar disorder.
Future treatments
If successful, the project could pave the way for a new generation of treatment approaches that are light-focused, experts say.
Bipolar disorder affects one in 50 people in Scotland. It is characterised by extreme mood swings ranging from depression to periods of manic behaviour, often with periods of relative stability in between.
“The study will help us to understand the complex relationship between light, circadian rhythms and treatment response. The findings could have major implications for the way that we treat bipolar disorder in the future.”
-Professor Daniel Smith, Project lead and Chair of Psychiatry at the University of Edinburgh’s Centre for Clinical Brain Sciences
Take part
Individuals aged 18 and over – both with bipolar disorder and those with no history of mental illness – are invited to register their interest via the study website: https://www.heliosbd.com/take-part
The study, funded by Wellcome, is being carried out in collaboration with Bipolar Scotland, the charity for people living with bipolar in Scotland. The project team includes partners from Northumbria University, Newcastle University and the Technical University of Munich.
“We are delighted to support this important research and hope the findings can lead to new and improved treatments for people with bipolar disorder. Working alongside the University of Edinburgh has provided opportunities for our members to be part of the Lived Experience Advisory Panel, and has helped to ensure that the lived experience of people with bipolar informs the development of this project.”
-Jayne Laidlaw, CEO of Bipolar Scotland
“We know lithium is an effective treatment for bipolar disorder, but this important research will help us understand if it helps patients by altering their response to light. This study is an example of the wider work we are supporting around ‘back translation’ – taking an existing effective approach in mental health and working backwards to understand exactly what makes it work. This information will help us refine existing mental health treatments and develop new ones.”
-Inês Pote, Research Lead in the Mental Health Evidence team at Wellcome
