a beautiful butterfly perched on an green grass of a meadow. Art view

Researchers studying single-cell blue-green algae or zebra fish, fruit flies or hamsters, often write at the bottom of their grant applications that, “Understanding basic mechanisms will help find new treatments for [this or that] illness.”  Indeed, universities that compete for glory, and politicians who deploy funding, want to see “translational research”, with results from a very fundamental level of behavior, biochemistry, or molecular genetics that can straightaway provide guidelines for improving human health.  This is pretty tough and not easy to achieve, certainly not in a one-step jump.

However, we in chronobiology have a unique advantage: there is a nearly ideal marriage between “algae people” and real people. Clock genes are similar throughout the plant and animal kingdom, and circadian rhythms follow the same rules. Thus. we can study their function in model organisms, and immediately reap the benefit for analogous human situations.  Basic and clinical researchers, both anchored to circadian physiology,  share the same language — we can really talk to each other!

The prime example is light therapy, which is indisputably the first treatment in psychiatry that directly arose from biology.  Recognizing that light hits the biological clock through the eye, and is responsible for synchronizing daily and seasonal rhythms, clinicians tried out light to the eyes as a therapy for patients who were depressed in winter. It worked — a great success story — and has led to an amazing surge of applications of light in all medical specialities where sleep and/or mood are out of sync.  Perhaps someone would have stumbled over light as a therapy for the same disorders, but it would have remained an esoteric alternative treatment. It would have lacked the advantages, methods, and feedback from basic research to validate its scientific integrity and justify acceptance by the medical establishment . . . to the benefit of millions of patients.


Anna Wirz-Justice PhD, Professor emeritus, is a founding member of the Society for Light Treatment and Biological Rhythms and the Daylight Academy, and Board member of the Center for Environmental Therapeutics, introduced light therapy to Europe and now focuses on the applications of chronobiology in architecture and daily life.