Environmental Therapeutics . . .

. . . harnessing neglected properties of light, dark, and air to meet the challenges of mental and physical health in contemporary life.

Therapeutic applications include:

  • seasonal affective disorder
  • non-seasonal depression
  • bipolar disorder (mania/hypomania)
  • mood changes during pregnancy
  • shift work disruption
  • sleep regulation and optimization
  • COVID isolation fatigue/stress
  • circadian rhythm adjustment

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For everyone

Reading and learning how to improve your sleep and mood.

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For professionals

A collection of resources and up-to-date information.

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Self-assessments with feedback

Take our unique, anonymous, automated self-assessments to track depressed mood, find the best time for you personally to start light therapy, and more.

Discover CET's free e-book collection

Our latest “Perinatal Depression: How Light Makes Pregnancy Brighter” is now available.

Light and Body Clock Therapy for Beginners

Internal Clock, Circadian Rythm, Chronotype, Chronotherapy, Seasonal Affective Disorder
Are some of these words or ideas new to you?
Start here!

Journal Watch
CET researchers scan the journals as soon as new issues are published and recommend the best in environmental therapeutics for our visitors to ponder.

Our New Lives With COVID-19

CET and friends in the research community offer a unique set of suggestions for dealing with sleep,
mood changes, and the virus itself – along with some noteworthy history about pandemics and vaccines.

Meet our experts, and a patient whose life turned around with light therapy, in a 6-minute video on seasonal and nonseasonal depression.

Ask Our Experts

Select a category that interests you.

We have a vast library of answered questions.

Faculty at Columbia, Yale, the University Hospitals of Basel and Copenhagen, the Russian Academy of Medical Sciences, and other top institutions around the world serve as our experts. Their cutting edge research offers snapshots of our interdisciplinary enterprise. Please note that the recommendations of our experts are not a substitute for the advice of your own physician or therapist.


I used to use my light box every time I had an important exam, it was the best choice I…

How do artificial electric light exposure and reduced natural light exposure both present health risks?

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We welcome your participation as well as your support.

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of the latest therapeutic and scientific advances.

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31 Harvard St, Worcester, MA, 01609

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