Center for Environmental Therapeutics



  • Do you have depression or Seasonal Affective Disorder (SAD)?

  • Are you curious or concerned about your circadian rhythm?

  • Are you sleeping the wrong hours?

  • Are you fighting fatigue when you need to be alert?

  • Do you need treatment for your symptoms but don't want to use medications?



  • We're here to help with these and other questions you might have. We offer a variety of services including background information, self-assessment questionnaires, and environmental therapy products. We are a 501(c)(3) nonprofit organization founded in 1994 in response to accelerating international interest in new environmental therapies.


    In the News



    Dr. Anna Wirz-Justice receives Velux Prize. Basel, Switzerland. CET is thrilled to share the news of this award from the Velux Foundation to Anna Wirz-Justice, our longtime Board member and Director of Chronotherapeutics Consultants. They write: “For the first time, the Velux Foundation, together with the Department of Architecture of the Swiss Federal Institute of Technology, has given this prize for lifetime achievement. With Anna Wirz-Justice, the Velux Foundation is rewarding a scientist who has had sustained impact on the understanding of daylight’s influence on health and wellbeing, as well as the application of light therapy for psychological disorders. As Professor Emeritus, Anna Wirz-Justice is now concentrating on the implications of her biological knowledge of light for the fields of architecture and building design.”



    New York Times: "Enter the Chronotherapists". New York, USA. We were glad to see this ambitious future-look at our field. Olivia Judson writes, "Here’s my prediction for the Next Big Thing in health care: chronotherapy, or therapy by the clock. . . . The implications of all this are huge. Living against your body clock — as so many of us do — can affect your health and well-being in myriad ways. . . . Chronotherapy has [been used] with great success . . . in psychiatry. Several mental disorders, including bipolar disorder, can be rapidly ameliorated by a resetting of the body clock. Indeed, it’s been argued that manipulating the body clock affects the same parts of the brain as antidepressant drugs — but that chronotherapy works faster and with fewer side effects." Read the whole story.


    Announcing a major publication from CET! Basel, Switzerland. After four years of preparation, testing and peer review, CET's Anna Wirz-Justice, Francesco Benedetti and Michael Terman published in 2009 a treatment manual entitled "Chronotherapeutics for Affective Disorders". As an international team with a strong chronobiology background and long experience in research and the clinic, they have integrated the practical details of light therapy, wake therapy (sleep deprivation) and sleep phase advance as effective antidepressants.


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    CHRONOTHERAPEUTICS FOR AFFECTIVE DISORDERS - Practical methods for implementing light and wake therapy against depression

    by Anna Wirz-Justice, Francesco Benedetti & Michael Terman

    This manual introduces chronotherapeutics for depression, a new synthesis of non-pharmacologic interventions designed to accelerate remission in bipolar and unipolar patients alike. It examines the underlying clinical research, explains the involvement of the circadian timing system, and provides hands-on instructions for treating inpatients and outpatients. Written by three of the most prominent experts in the research and clinical applications of chronotherapy, this book enables clinicians to implement its principles and let their patients benefit from its practicality and effectiveness. Read the Reviews in Acta Psychiatrica Scandinavica (English) or Schweizer Archiv für Neurologie und Psychiatrie (German).



    CET's Mission



    CET's mission is to serve patients, consumers, health care providers and workplace managers to:


  • Educating the public, students and professionals about effective use of environmental therapies.

  • Offering authoritative information on non-medication treatments for seasonal affective disorder, nonseasonal depression and circadian rhythm sleep disorders.

  • Fostering research on environmental interventions that promote alertness, energy, and performance — while combating fatigue, stress, depression and sleep disturbances that affect millions of people.