Young woman sitting in front of closed wooden window with sunlight streaming in
theresa with light box
Light boxes that meet certain criteria, such as the BOXelite OS shown here, can relieve symptoms of SAD.

CET does not recommend trying light therapy, or any other circadian rhythm treatment, without the supervision of a professional. Although side effects are rare, it is critical to have someone who can recognize them, and treat them. Patients may not be able to do so because they lack the necessary training, and objectivity.

We recognize, of course, that not everyone with circadian rhythm issues is affected at clinical severity, and tweaks of the rhythm – especially using light therapy – can be safely self-administered following the advice and cautions we have provided on our website.

If you are interested in light therapy, please:

As an example of a severe side effect, wake therapy might cause a patient with bipolar depression to begin to become manic―although this side effect occurs no more often than with antidepressants, perhaps in 5% of cases. If this were to occur, it would be necessary to have a professional who could recognize what was happening, and intervene, since people who become manic typically do not notice that anything is amiss.


Upon request, the nonprofit Center for Environmental Therapeutics will try to refer individuals to professionals licensed to practice in their state who are familiar with chronotherapy. Information about licensure is based on information given to CET by the professionals. CET provides referrals as a service to the community, and these listings are not meant as endorsements of specific professionals, and do not in any way guarantee treatment or evaluation outcomes.

CET does not determine, or guarantee, the competence of any professional provided as a referral. Consequently, use of referrals from CET will not result in any liability against CET. In no event shall CET be liable for damages to anyone for the voluntary selection of a professional, for the services provided by any professional, or for any other damages which may occur. CET cannot and does not provide any warranties related to the information about, or resulting services from, a professional listed on the CET web site, or given to an individual as a possible referral.

Unfortunately, few professionals as yet are familiar with chronotherapy or have integrated it into their practice.  Prospective patients in any locality may find that the onus is on them to encourage their doctors and mental health specialists to learn the principles and techniques of chronotherapy in order to monitor and supervise the treatments with confidence.

Treatment in the Absence of Experts in Chronotherapy

If the professionals near you are unfamiliar with light therapy and related techniques, they may be willing and interested to learn about these methods so they can treat you. We recommend that these professionals start by reading our free, five-page guide for doctors and allied clinicians, available at Light Therapy for Major Depression:  A Game Changer for Physicians. Consider printing out a copy and sharing it with them.

After reading the free guide, we recommend the short, but definitive, clinical manual in chronotherapeutics, Chronotherapeutics for Affective Disorders: A Clinician’s Manual for Light and Wake Therapy by Drs. Anna Wirz-Justice, Francesco Benedetti, and Michael Terman. This book is organized for busy clinicians who want to find, and learn, exactly what they need to know to treat a given patient. The book focuses on making clinically relevant information accessible, along with background on the research which led up to these pace-setting applications.

Another way to get your clinician involved is to print out the results and interpretation guides that accompany our online, personalized self-assessment questionnaires, which focus on seasonal mood variation, circadian rhythm state, and depressed mood.  These can help focus attention on your specific concerns, and stimulate productive discussion at office visits.

CET is dedicated to helping patients and clinicians alike.  Chronotherapy is based on clear principles and demonstrated treatment successes both in controlled clinical trials and open treatment by pace-setting clinicians.  Your involvement helps the field grow and become more widely accessible.