Download Photo Therapy - Association for Academic Psychiatry

Phototherapy
Nadejda Alekseeva, MD
PGY-IV Resident
Department of Psychiatry
LSUHSC-September 2006
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
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
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
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
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
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
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
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)
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
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
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
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
• What are the 4 components of bright
light therapy?
• The 4 components of bright light therapy
are:
• Intensity
• Timing
• Duration
• Wavelength
• What light intensity is necessary for
melatonin suppression?
• Light intensity greater than 2000 lux is
necessary for melatonin suppression in
most people
• What is the recommended use of bright
light box in SAD?
• 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
• 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
• How long does it take to show a response
to bright light?
• 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
Light Therapy
• Has an overall positive treatment response
of up to 70%, with rarely any side effects
• Combination of LT and CBT demonstrated
a lower remission rate than LT alone
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
• 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
• 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