The effect of ambient bright light therapy on depressive symptoms in persons with dementia

J Am Geriatr Soc. 2007 Nov;55(11):1817-24. doi: 10.1111/j.1532-5415.2007.01428.x. Epub 2007 Oct 16.


Objectives: To assess the effect of ambient bright light therapy on depressive symptoms in persons with dementia.

Design: A cluster-unit crossover intervention trial involving four lighting conditions: morning bright light, evening bright light, all-day bright light, and standard light.

Setting: The common areas of two geriatric units in a state-operated psychiatric hospital in North Carolina and in a dementia-specific residential care facility in Oregon.

Participants: Sixty-six older adults with dementia.

Intervention: Ambient bright light therapy was delivered through a high-intensity, low-glare lighting system installed in the public areas of study units at both sites. Each lighting condition was provided for multiple 3-week periods in a predetermined sequence.

Measurements: Staff caregivers completed the Cornell Scale for Depression in Dementia (CSDD) in the last week of each 3-week period to provide information about participants' moods.

Results: Analysis indicated a sex-by-treatment interaction (P=.008). Significant sex differences were found in CSDD scores in response to evening light (P=.003), all-day light (P=.001), and standard light (P</=.001). Depressive symptoms were lowest for women and highest for men during morning light.

Conclusion: Findings do not support the use of ambient bright light therapy as a treatment for depressive symptoms in persons with dementia, although a subpopulation of persons with dementia may benefit from this intervention. It is likely that individual rather than unit-level interventions are a more effective strategy for delivering bright light therapy for this population.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / diagnosis
  • Alzheimer Disease / psychology
  • Alzheimer Disease / therapy*
  • Circadian Rhythm
  • Cross-Over Studies
  • Depression / diagnosis
  • Depression / psychology
  • Depression / therapy*
  • Female
  • Geriatric Assessment
  • Hospitals, Psychiatric
  • Hospitals, State
  • Humans
  • Male
  • Middle Aged
  • North Carolina
  • Oregon
  • Personality Assessment
  • Phototherapy*
  • Social Environment
  • Treatment Failure