www.BeTreatedWell.com Seasonal Depression
As the days become longer more people begin to notice the impact that daylight
has upon our bodies. Though most people know that light is essential to
regulation of our internal biological clock, only some know that light also plays a
role in the regulation of mood, and even fewer understand the biological process
that explains the relationship between darkness and depression.
Years ago, Dr. Norman Rosenthal at the National Institute for Mental Health found
that some patients became very sluggish, irritable, and depressed as days grew
shorter. They slept excessively, binged on carbohydrates, and withdrew from
social activities. In essence, their depressed behavior replicated a mild form of
primitive biological hibernation.
This type of mood change in response to the decreased exposure to daylight is
known as Seasonal Affective Disorder (SAD). The incidence of SAD in various
regions of the world is directly related to each particular region’s distance from the
equator. That is, SAD is found with higher frequency in locations furthest from the
tropics, where there are fewer hours of daylight.
For those with SAD, the critical variable is not the season, nor the climate, nor
other situational factors such as changes in employment status. The depression is
activated and deactivated by the amount of daylight.
There is a biological explanation of the mechanism:
Light entering our eyes through the retina transmits impulses along the optic
nerve to the hypothalamus. This brain structure controls numerous activities
including sexual urges, thirst and hunger, body temperature, aggression, and
emotions such as pleasure and sadness.
The hypothalamus transmits information about light to the pineal gland which
regulates the production of melatonin which acts on the hypothalamus. Melatonin
induces sleep, decreases mental agility and appears to depress mood. Absence of
light results in increased melatonin secretion and SAD.
SAD can be effectively treated via various behavioral changes. Maintaining a
regular sleep and wakefulness schedule even on weekends and getting regular
exercise can combat some of the symptoms. In addition, use of a specially
designed light box which mimics sunlight can also be very helpful.
Light therapy has been used to treat SAD since the 1980’s. These specially
designed light boxes contain high intensity full-spectrum light bulbs placed behind
a diffusing screen which filters out the glare and almost 100% of the UV rays.
The light emitted from a typical box at a comfortable distance is equivalent to a
clear sunny spring morning. Exposure times of as little as 15 to 30 minutes a day
are sufficient to halt melatonin production. Exposure in the morning is
recommended for those who struggle to wake up during the winter months.
Exposure in the evening is preferable for those who feel sleepy in the early
evening.
If you think that you may have SAD it is important that you consult a professional
in order to get an accurate diagnosis. Light therapy will not help if your symptoms
are not the result of SAD. Before starting light therapy it is important to rule out
other diagnoses which would require other treatments, and to take precautions
and evaluate contraindications for the use of a light box.
As the days become longer more people begin to notice the impact that daylight
has upon our bodies. Though most people know that light is essential to
regulation of our internal biological clock, only some know that light also plays a
role in the regulation of mood, and even fewer understand the biological process
that explains the relationship between darkness and depression.
Years ago, Dr. Norman Rosenthal at the National Institute for Mental Health found
that some patients became very sluggish, irritable, and depressed as days grew
shorter. They slept excessively, binged on carbohydrates, and withdrew from
social activities. In essence, their depressed behavior replicated a mild form of
primitive biological hibernation.
This type of mood change in response to the decreased exposure to daylight is
known as Seasonal Affective Disorder (SAD). The incidence of SAD in various
regions of the world is directly related to each particular region’s distance from the
equator. That is, SAD is found with higher frequency in locations furthest from the
tropics, where there are fewer hours of daylight.
For those with SAD, the critical variable is not the season, nor the climate, nor
other situational factors such as changes in employment status. The depression is
activated and deactivated by the amount of daylight.
There is a biological explanation of the mechanism:
Light entering our eyes through the retina transmits impulses along the optic
nerve to the hypothalamus. This brain structure controls numerous activities
including sexual urges, thirst and hunger, body temperature, aggression, and
emotions such as pleasure and sadness.
The hypothalamus transmits information about light to the pineal gland which
regulates the production of melatonin which acts on the hypothalamus. Melatonin
induces sleep, decreases mental agility and appears to depress mood. Absence of
light results in increased melatonin secretion and SAD.
SAD can be effectively treated via various behavioral changes. Maintaining a
regular sleep and wakefulness schedule even on weekends and getting regular
exercise can combat some of the symptoms. In addition, use of a specially
designed light box which mimics sunlight can also be very helpful.
Light therapy has been used to treat SAD since the 1980’s. These specially
designed light boxes contain high intensity full-spectrum light bulbs placed behind
a diffusing screen which filters out the glare and almost 100% of the UV rays.
The light emitted from a typical box at a comfortable distance is equivalent to a
clear sunny spring morning. Exposure times of as little as 15 to 30 minutes a day
are sufficient to halt melatonin production. Exposure in the morning is
recommended for those who struggle to wake up during the winter months.
Exposure in the evening is preferable for those who feel sleepy in the early
evening.
If you think that you may have SAD it is important that you consult a professional
in order to get an accurate diagnosis. Light therapy will not help if your symptoms
are not the result of SAD. Before starting light therapy it is important to rule out
other diagnoses which would require other treatments, and to take precautions
and evaluate contraindications for the use of a light box.
| Antonia Caretto, Ph.D., PLLC |
| www.BeTreatedWell.com phone: 248.553.9053 |
| Articles of Interest: Business of Therapy Anxiety Why Gender? Asperger's Disorder Adjustment Disorders Self-Injurious Behavior |
