Lighting the Way

Research can have an impact in many ways. The creation of clinical guidelines, while not as obvious as the introduction of a new drug or device, is one such way; herein, an illuminating success story

Psychiatrist Dr. Anthony Levitt co-penned the definitive guidelines on how to treat seasonal affective disorder.

Photo: Doug Nicholson

Since the early 1980s researchers have been investigating how disorders of one’s biological clock and the processing of light affect psychiatric illnesses. They have found that seasonal affective disorder (SAD), or winter depression, is a distinct subtype of clinical depression and that light therapy—daily exposure to bright, artificial light—is an effective treatment.

Although a growing number of papers were being published on SAD two decades ago, there were no summary guidelines to provide health care professionals with a “go-to” resource when diagnosing and treating patients.

Starting in 1994, Dr. Raymond Lam and Dr. Anthony Levitt, experts in mood disorders and SAD, organized the Canadian Consensus Group. It comprised the country’s top researchers in the field and sought to answer commonly asked questions about SAD. The members of the group reviewed the scientific literature, and from this formulated evidence-based recommendations for the diagnosis and treatment of SAD. The result was the Canadian Consensus Guidelines for the Treatment of Seasonal Affective Disorder. The book was published in 1999 in a question-and-answer format for use by family doctors, psychiatrists, psychologists, nurses and other health care professionals.

“We felt it was important to bring experts together because we figured it’s going to be decades, if ever, before we can conduct the research needed to answer all the clinical questions that would form the basis of best-practice guidelines,” says Levitt, who is a psychiatrist at Sunnybrook and scientist in the Brain Sciences Research Program at Sunnybrook Research Institute (SRI).

“The guidelines have had an impact internationally, and there have not been any published since,” he adds.

Fifteen years later the guidelines are still relevant—and needed more than ever. The prevalence of SAD is about 2.6% of the Canadian population, and about 50% of Canadians say they have difficulty with their mood or energy after autumn’s end. “It’s an interesting public health issue: people are reporting a significant change in their mood and energy in the winter time, resulting in noticeable problems with their life and function, even though they are not clinically depressed,” says Levitt.

The guidelines have educated a whole generation of consumers and patients.

The guidelines have had an impact on practice and policy. Levitt says family doctors and psychiatrists are making use of them for educational purposes. For example, he notes universities are using them to teach residents about the treatment of SAD, and some family doctors are lending the book to patients to help them understand the condition.

"The guidelines have educated a whole generation of consumers and patients for whom this information was not available in one spot. We get lots of feedback from patients who like that we’ve written a book on guidelines that is also a self-help book,” says Levitt, who is also a professor at the University of Toronto. Many physicians across Canada also requested—and received at no cost—copies of the book, making its true impact hard to quantify.

Insurance companies were also persuaded to cover light therapy as a result of the guidelines, supported by other research. “In terms of policy, we've been able to convince insurance companies that it's reasonable for them to cover the cost of light therapy units because, in the end, it’s less costly than medications," he says.

Levitt says that perhaps the biggest impact of the guidelines has been that they led to the development of other such tools for managing mental illness. One example is the Guidelines for Adolescent Depression in Primary Care developed by Levitt’s colleague, Dr. Amy Cheung, a clinician-scientist in the Brain Sciences Research Program at SRI.

Cheung, together with pediatricians, family doctors and scientists, created the publication to address the lack of research-based evidence and recommendations for the management of depression in youth. “Her guidelines have precipitated further research and the development of programs internationally—it’s been a really valuable exercise,” Levitt says.

The SAD guidelines not only addressed questions about diagnosis and treatment, but they also helped identify knowledge gaps and promote research. “When we published the guidelines, the rate of increase in the number of publications in seasonal depression was astronomical,” says Levitt.

Guidelines are often updated as new knowledge surfaces, and Levitt says he can see this happening here, too. “It would be worth looking back and saying, ‘How have things changed, and what’s important?’ It wouldn’t require a whole book, but more likely a review of progress.”

Light therapy has become a widely accepted treatment for SAD, followed by antidepressants and psychotherapy. Relatively new to the arena are two types of devices: head-mounted light units, which sit on the head at a fixed distance from the eye; and dawn-simulation units, a technique that uses a digital clock and gradually increases lighting in the bedroom hours before awakening. The use of LED lights, as opposed to fluorescent lights, has also changed treatment, making therapy units more compact and portable.

As for the direction the field is going, Levitt points to neuromodulation, a process that involves direct stimulation of brain structures to adjust disrupted brain circuitry. Neuromodulation alters nerve activity by delivering physical stimulation directly to an area of interest in the brain; this stimulation may be electrical, magnetic, ultrasound or other; indeed, as Levitt notes, light therapy is photic stimulation of the retina, which is actually part of the brain.

Scientists at SRI are at the forefront of this kind of neuromodulation research, preclinically and with patients for certain conditions—though not yet in depression. (Click here for more.) Levitt says he’s optimistic that the first human trials with new forms of neuromodulation are just around the corner.

"The new phase of therapeutics for mental illness is about neuromodulation, and we already have evidence that neuromodulation using light therapy works in seasonal depression. This kind of treatment represents an amazing opportunity for our patients to feel better and stay well," he says.

Still, treatment of psychiatric illness is one thing; stopping it from happening is another. “The field has been focused on treating people when they get sick, but where the field needs to go is prevention. Seasonal affective disorder is one condition that you can look carefully at prevention because you know when it’s going to start. I think the field is now moving toward prevention.”

— Eleni Kanavas

This research was funded by the Canadian Institutes of Health Research, Ontario Mental Health Foundation and Physicians' Services Incorporated Foundation.