The prevalence of sleep problems in adulthood increases with age. While not all sleep changes are pathological in later life, severe disturbances may lead to depression, cognitive impairments, deterioration of quality of life, significant stresses for carers and increased healthcare costs. The most common treatment for sleep disorders (particularly insomnia) is pharmacological. The efficacy of non-drug interventions has been suggested to be slower than pharmacological methods, but with no risk of drug-related tolerance or dependency.
Bright light treatment involves participants sitting in front of a "light box" which emits very high (typically 10,000 lux) fluorescent light for periods of around two hours daily. The timing of this light treatment will depend on the irregular timing of the participant's sleep pattern.