Bright Light Therapy Linked With Higher Rates of Bipolar Disorder Remission

Dorothy Sit, MD, recently presented a session on the current clinical indications of bright light therapy and discussed novel visual and neural biomarkers in patients with bipolar depression at the virtual 2021 American Psychiatric Association (APA) Annual Meeting. The session explored relevant studies to examine the approaches in managing antidepressant treatment in perinatal women and reflect on Dr. Sit’s career in research, education, and advocacy of women’s health.

In this Q&A, conducted before her session, presenter Dr Sit discussed some of the topics she would address in the session "Bright Light Therapy for Treatment of Bipolar Disorder” including her recent study that found patients given bright light therapy experienced higher rates of full response and remission compared to the placebo comparator.

In the upcoming Part 2, Dr Sit discusses her current research on obstetrical and psychiatric care drug concentrations and the practical implications of her findings for clinicians treating patients with bipolar disorder.

Read the transcript: 

Hi, my name is Dr. Dorothy Sit. I am an associate professor in the Department of Psychiatry and Behavioral Sciences at Northwestern University's Feinberg School of Medicine. I am here today to present a talk for the Alexandra Simmons Award.

Q: What are the main points or messages from your upcoming session, “Bright Light Therapy for Treatment of Bipolar Disorder”? (00:29)

A: The main points, or objectives, or messages from this session would include the following.

The first objective is to discuss the known and novel clinical indications of bright light therapy, particularly for the treatment of seasonal affective disorder, nonseasonal major depression, bipolar depression, and perinatal depression.

Objective 2 is to examine the outcome measures of light therapy response that are relevant to patients who have bipolar disorder, examining their remission rates, depression scores, changes in functioning, other measures that could help gauge response, including their sleep quality, chronotype, the level of seasonality in their mood symptoms, and also the risk for mood polarity switch.

Objective 3 is to explore and discuss some of the putative novel visual and neural biomarkers that we can examine in understanding the response to bright light therapy in patients who have bipolar depression.

The fourth objective is to segue into some of the work that encompasses the phenomenology, pathophysiology, and pharmacological responses in women across the life cycle and to examine and discuss the approaches in the management of antidepressant therapy in perinatal women, given our study findings.

Objective five is a reflection on a career path in psychiatry that encompasses research, clinical care, teaching and education, and advocacy of women's mental health.

Q: Please briefly describe the methods and key findings from the study you will be discussing in your session. (2:24)

A: In this program, I will discuss the methods and key findings from our primary study, which has to do with examining bright light therapy as an adjunctive treatment for bipolar depression.

To give it a little bit of context, conventionally, bright light therapy that is used for the treatment of seasonal affective disorder and other types of depression are administered in the morning time. Usually, treatment is implemented for 30 minutes shortly after awakening.

Used daily, it can improve seasonal affective symptoms within 2 to 4 weeks. The onset is very quick and usually within 3 to 4 days.

In our earlier case series report, we implemented the morning light therapy to patients who had bipolar depression were maintained on mood stabilizers. Intriguingly, 3 out of the 4 patients who were first enrolled in this study experienced an induction of hypomania and mixed symptoms rapid-cycling within days after starting treatment.

Upon careful literature review and consultation with experts, we made adjustments to our protocol, adjusted the timing of light therapy to a midday time period. By doing so, we recruited 5 more patients, of which 3 experienced a full response, and 1 responded fully to the transition of morning light.

What we did find in our earlier case series trial is that mid-day light may produce a promising therapeutic effect for bipolar-depressed patients. Given the promising findings, we then conducted a randomized controlled trial to confirm the efficacy of adjunctive midday bright light for bipolar depression.

We compared patients randomized to bright light therapy at midday with patients who were administered a placebo-controlled comparator. We'll discuss that more in the talk.

After 4 to 6 weeks, we discovered that 67% of patients given bright light therapy experienced a full response and remission compared to only 33% who were randomized to the placebo comparator.

In this talk, we will look at not only the primary outcomes, which included remission rates, changes in functioning, and the risk of mood polarity switch, which was very minimal to none. Also, we'll examine secondary outcome measures that may or may not be as predictive of the response that we're looking for, things like sleep quality and the patients' baseline chronotype.

We will explore this a little bit more in-depth and discuss not only the methods but some of the primary and secondary outcome measures that may be of interest.