Dear HEALTHbeat subscriber,

The “winter doldrums” — that time period when winter's darkness remains and the march toward spring feels particularly long — can leave many of us feeling a little down. For some, the meager daylight hours during this time of year can lead to a form of depression called seasonal affective disorder (SAD). This issue of HEALTHbeat discusses new treatment options for SAD sufferers. Also, Dr. Celeste Robb-Nicholson, editor in chief of the Harvard Women’s Health Watch, discusses treatments for an overactive bladder.

Wishing you good health,


Nancy Ferrari
Managing Editor
Harvard Health Publications
HEALTHbeat@hms.harvard.edu

Traditional light therapy

Fluorescent light boxes are most often used to deliver traditional bright light therapy. Patients usually expose themselves to 30 minutes of light. Bright white light acts on cells in the retina that connect to the hypothalamus, a part of the brain that helps control circadian rhythms, which are somehow disrupted in seasonal affective disorder.

Two reviews of multiple studies on light therapy, which included only randomized controlled trials, concluded that bright light therapy was as effective at treating seasonal affective disorder as antidepressant therapy, and in some cases more effective.

But investigators have sought to improve on traditional light therapy for three reasons. First, it doesn’t work for everyone. Different studies have reported that 50% to 80% of patients achieve complete relief from depressive symptoms after bright light therapy — and remission may depend upon carefully individualized timing of light.

Second, dosing remains a major question. Dose depends on the strength of the light source, the patient’s distance from the light box, light wavelength, and duration of exposure. The recommendation for 30 minutes of daily exposure is based on average response to white light; some patients may not need that much exposure to benefit, or may experience adverse side effects from that amount. Others — such as parents of toddlers — may not be able to sit in front of a device for 30 minutes each morning.

Finally, side effects of bright light therapy, while mild for many patients, may be more of a concern for others. For example, bright light therapy may trigger hypomania or mania in patients with bipolar disorder, which is why mood-stabilizing medications are often recommended at the same time. And while the risk of retinal damage from light therapy is small over all, some medications and medical conditions increase the risk for some patients.

Enhancing light therapy

Investigations are under way to see if changing the timing of light therapy, or using particular wavelengths of light, might improve response or reduce risk of side effects like mania or retinal damage.

Better timing. Researchers from Columbia University reported that remission from seasonal affective disorder was twice as likely if light therapy was precisely calibrated to melatonin rhythms. They found that 80% of patients achieved remission if light therapy began 7.5 to 9.5 hours after an evening melatonin surge, compared with 38% of patients whose light therapy began 9.5 to 11 hours afterward. Individual melatonin shifts may vary by five to six hours.

Dawn simulation. In this variation of light therapy, a preset light device turns on before a patient awakens. Light intensity increases gradually over a period of 90 minutes. Although the studies so far have been small, they have also been promising.

Blue light. Traditional devices use white light, a mixture of all the colors (such as blue, green, and red) in the visible light spectrum. The use of light-emitting diode (LED) technology has made it possible to create smaller and more portable devices and test specific wavelengths of light.

Studies have found that ganglion cells in the retina are particularly sensitive to blue light, suggesting that this wavelength may powerfully affect circadian rhythms. Researchers are investigating whether blue light might provide the same benefit as white light but with less exposure time — which might reduce risk of side effects in vulnerable patients.

Current guidance

Experts recommend that patients with seasonal affective disorder first try traditional bright white light therapy after awakening. If it does not help or creates bothersome side effects, it may be worth trying antidepressants or one of the alternatives under investigation.

The FDA does not test, approve, or regulate light box devices, so patients considering buying any device should ask about the wavelengths it emits and check to see if it has been used in any reputable research facilities.

For more information on seasonal affective disorder and other forms of depression, order our Special Health Report, Understanding Depression at www.health.harvard.edu/UD.

Q: I suffer from an overactive bladder that hasn’t responded to the usual treatments. My urologist is recommending an Interstim neuromodulator. What are the pros and cons of this therapy?

A. The Interstim neuromodulator is a small, surgically implanted device that’s used to treat the symptoms of overactive bladder, a condition in which the bladder muscles contract suddenly, causing an abrupt and urgent need to urinate and sometimes urine leakage or incontinence. Many women with overactive bladder also have urinary frequency, that is, a need to urinate more than eight times during a 24-hour period, or two or more times at night.

Interstim therapy sends mild electrical pulses to the sacral nerves, which lie just above the tailbone and control bladder muscle contractions. The electrical pulses help to correct faulty signals between the bladder and brain and improve external sphincter tone. Studies have shown that Interstim therapy helps reduce day and nighttime frequency as well as episodes of uncontrollable urgency.

The Interstim neuromodulator doesn’t work for everyone, so it’s fully implanted only after a trial run. For the trial, one end of a special wire is surgically placed near a sacral nerve, and the other end is connected to an external device worn at the waist. If symptoms improve within about a week, a permanent neuromodulator is implanted under the skin of the upper buttock and connected to the sacral nerve by way of a wire tunneled under the skin. The trial and implant procedures are usually performed as day surgery under local anesthesia. Patients can return to normal activities in three to six weeks. The device is small (about the size of a stopwatch) and lightweight (less than 2 ounces).

Interstim is approved for use in women with severe symptoms of urinary urgency or frequency that have not improved with conservative treatments. Like all surgery, there are some risks, including pain where the stimulator is implanted, infection, bleeding, and shifting of the unit or wires over time, which may require surgical correction. The batteries last for three to 12 years and aren’t rechargeable; an incision must be made to remove and replace them. Interstim implantation (including the cost of the device) is expensive, but many insurers as well as Medicare cover the procedure.

Before you consider surgery, you should exhaust all the noninvasive options, including these:

• Adjust your fluid intake, especially before bedtime, to reduce nighttime frequency. Avoid caffeine and alcohol, which stimulate urination.
• Try bladder training, such as timed voiding, which can often help extend the time between trips to the bathroom.
• Practice pelvic floor exercises (Kegels), which help strengthen the muscles that support the bladder, reducing the likelihood of leakage.
• Consider taking an anticholinergic drug — for example, Detrol or Ditropan. These drugs act in the nervous system to relax bladder muscles and prevent the contractions that cause feelings of urgency. However, many women can’t tolerate the side effects, which may include dry mouth and, less commonly, blurred vision, constipation, facial flushing, and rapid heartbeat.

If you decide to try Interstim, be sure to consult a urologist with plenty of expertise in implanting and using the system.

This Question and Answer first appeared in the November 2008 Harvard Women’s Health Watch, available at www.health.harvard.edu/women.

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