There are great interindividual differences in people's melatonin response to light, which can affect how clinicians treat many neuropsychiatric disorders.
Exposure to light affects circadian rhythm by altering melatonin activity and can influence seasonal affective disorder, bipolar depression, and mania. However, do individuals vary in the intensity of light that would suppress melatonin secretion? These researchers obtained data on 56 healthy people (29 women) to determine group- and individual-level dose-response curves at seven light intensities (range, 10–2000 lux).
After 1 week of dim-light exposure, participants received weekly randomized exposure to various light intensities starting 4 hours before habitual bedtime (study total, 351 nights). Measurement of melatonin suppression from light exposure was based on individuals' baseline melatonin onset in dim light.
Overall, the mean effecti…
Reviewing Author
DisclosuresRoyaltiesTextbook of Traumatic Brain Injury, 2nd and 3rd editions
Editorial BoardsUpToDate; Journal of Neuropsychiatry and Clinical Neuroscience
Leadership Positions in Professional SocietiesNorth American Brain Injury Association (Board Member); National Institute on Disability, Independent Living, and Rehabilitation Research (Chair of Data Monitoring Safety Board for study of donepezil on cognition after traumatic brain injury)
DisclosuresRoyaltiesTextbook of Traumatic Brain Injury, 2nd and 3rd editions
Editorial BoardsUpToDate; Journal of Neuropsychiatry and Clinical Neuroscience
Leadership Positions in Professional SocietiesNorth American Brain Injury Association (Board Member); National Institute on Disability, Independent Living, and Rehabilitation Research (Chair of Data Monitoring Safety Board for study of donepezil on cognition after traumatic brain injury)