There is much criticism about the effects of blue light emanating from modern devices, such as smartphones, as the light disrupts our circadian rhythm and leads to problems with sleep. On the other hand, there is much research looking to harness blue light to overcome medical issues, such as using blue light to kill off bacteria that causes infections in skin and soft tissues.

Scientists also think blue light can be used as treatment for common concussion symptoms – a team at the University of Arizona (UA), US, has found that by subjecting people with a mild brain injury to a dose of blue light each morning, they could help to reduce some of its typical side effects, including depression.

UA’s preliminary study involved 35 young adults, with all experiencing a concussion within the past 18 months. Some participants were subject to bright blue light for 30 minutes each morning – from a tabletop device – while some received amber light as a placebo. This was done over a period of six weeks.

At both the outset end endpoint of the study, all participants completed tests to assess different symptoms of their concussions, including depression, headaches, fatigue and trouble with sleep, memory and concentration.

Those undergoing the blue light therapy were revealed to have improved by an average of 22% on the Beck Depression Inventory, a standard depression test. The significantly improved scores were linked to relief from concussion symptoms like sleep disturbance, fatigue, concentration, restlessness, and irritability; while the placebo group exhibited only a 4% worsening in mood.

Study author William D. Killgore comments, “These results reinforce that blue light therapy may be an effective, non-drug treatment for concussion and that improvements in depression may result in improvement in both mental and physical concussion symptoms, and thus quality of life.”