Phototherapy Nadejda Alekseeva, MD PGY-IV Resident Department of Psychiatry LSUHSC-September 2006

1. Phototherapy Nadejda Alekseeva, MD PGY-IV Resident Department of Psychiatry LSUHSC-September 2006

2. Light Therapy (LT) The least invasive, most natural and effective treatment of Seasonal Affective D/O (SAD) The original theory behind LT was that it would cause a normalization of the phase-shift delay in SAD, to lengthen the photoperiod in winter in those with SAD and to suppress the production of melatonin by the pineal gland

3. Seasonal Affective Disorder • There is much more seasonal difference in higher latitudes than in the lower • In a significant portion of the population of the northern US, the shorter days of fall and winter precipitate SAD

4. Seasonal Affective Disorder • SAD is a syndrome that can consist of depression, fatigue, hypersomnolence, hyperphagia, carbohydrate craving, weight gain, and loss of libido • If these symptoms persist in the winter, abate as the days grow longer, and disappear in the summer, the diagnosis of SAD can be made

5. Seasonal Affective Disorder • Melatonin from the pineal gland has been implicated in SAD • Some individuals with SAD go to the other extreme in the spring and summer, experiencing a manic state

6. Seasonal Affective Disorder • DSM Criteria for SAD: • -can be applied to the pattern of MD episodes in Bipolar I d/o, Bipolar II d/o or MDD recurrent • -there has been a regular temporal relationship between the onset of MD episode (appearance of MD episode in winter) • -full remission or change to mania in spring • For the last 2 years, 2 SAD episodes

7. Epidemiology of SAD • Incidence of SAD in the general population is 4-10%, with a higher incidence in women than men • SAD incidence increases in population further North • People from Southern latitudes who move North may have an increased risk of SAD • Some individuals develop a tolerance to seasonal changes over time

8. Seasonal Affective Disorder • Decreased exposure to sunlight in the winter increases the risk of SAD • But studies of populations native to Iceland discovered a possible genetic adaptation to the low light of winter in the arctic • This population had a SAD prevalence of 1.2% • Another genetic finding: SAD occurs more often in relatives of those with SAD

9. Seasonal Affective Disorder • The most commonly used SAD diagnostic research tools are the: • -Seasonal Pattern Questionnaire (SPAQ) • -Structured Interview guide for the Hamilton Depression rating-Seasonal Affective D/O (SIGH-SAD)

10. Mechanisms of Seasonal Changes in SAD • Individuals with SAD have longer periods of melatonin synthesis at night in the winter • Melatonin synthesis is triggered by darkness • Melatonin synthesis can be suppressed by application of LT

11. Role of Melatonin • Melatonin is the immediate downstream metabolite of serotonin • Low brain level of serotonin might contribute to SAD symptoms (hyperphagia and carb cravings) • Increased carb cravings in SAD may be a coping mechanism that stimulates the release of serotonin

12. Light Therapy • Is a natural, noninvasive, effective, well-researched method of treatment for SAD • Various Light temperatures and times of administration of LT have been studied • Combination of morning and evening exposure appears to offer the best efficacy

13. Light Therapy • Been used to suppress the production of melatonin by the pineal gland • Light enters the retina, which in turn stimulates the suprachiasmatic nucleus of the hypothalamus • This in turn inhibits the pineal gland from converting serotonin to melatonin

14. What are the 4 components of bright light therapy?

15. The 4 components of bright light therapy are: • Intensity • Timing • Duration • Wavelength

16. What light intensity is necessary for melatonin suppression?

17. Light intensity greater than 2000 lux is necessary for melatonin suppression in most people

18. What is the recommended use of bright light box in SAD?

19. Exposure to the eyes of diffuse visible light with an intensity of at least 2500 lux daily, preferably in AM, for at least 2 h • Most light boxes produce 2500 lux at a distance of 3 feet, and light intensity is inversely related to the square root of distance of the eyes to the light source

20. Using the 2500 lux box at 1.5 feet from the eyes produces 10,000 lux, and the duration of treatment can be reduced, as 30 min at 10,000 lux is equivalent to 2 h at 2500

21. How long does it take to show a response to bright light?

22. Response to bright light therapy usually begins within 3 to 4 days, with full response in 1 to 2 weeks • when LT stopped, relapse can occur in 3 to 4 days

23. Light Therapy • Has an overall positive treatment response of up to 70%, with rarely any side effects

24. Combination of LT and CBT demonstrated a lower remission rate than LT alone

25. Light Therapy • Experimental treatment extended to other conditions: • Non-seasonal mood d/o • Alzheimer’s disease • Circadian-related sleep d/o • Jet lag • Eating d/o

26. LT improves nocturnal sleep in people with dementia • LT reverse age-associated disturbances of circadian sleep-wake rhythm • LT prevent the age-associated decrease in the number of vasopressin-secreting neurons in the suprachiasmic nuclei of the hypothalamus

27. Despite the growth in clinical and research programs, there is an absence of recognition and support for LT • Most insurers do not pay for this treatment • Most residency training programs do not provide training in Light Therapy