Seasonal affective
disorder (SAD) is a serious form of depression that occurs around the same time
each year with the changing of the seasons. Researchers have identified two types
of SAD seasonal depression with the most common type being "winter
depression" beginning in the late fall to early winter months and ending in the
spring. The second type of seasonal affective disorder occurs in the summer and
is known as "summer depression". Of the 4 to 6 percent of the population that
suffer from seasonal affective disorder 70 percent are women with
symptoms usually beginning in the person's early twenties. A much larger portion
of the population suffers from a less severe form of seasonal disorder called
the "winter blues". Getting over the winter
blues is a task that many affected individuals must face with the changing
of the seasons.
The exact causes of SAD are unknown, but is believed to
be based to some extent on our body's natural reaction to the changing light levels
in our environment. Statistics show that the winter blues and seasonal affective
disorder become much more common, last longer, and are more severe at higher latitudes.
Getting over the winter blues maybe harder for some because exposure to light
levels in our environment influence the body's production of certain hormones,
specifically serotonin and melatonin.
Serotonin is a neurotransmitter that
helps to maintain many body functions as well as to help maintain emotional balance.
Ninety percent of the body's serotonin is in the abdomen with the rest being found
in the pineal gland of the brain and blood platelets. Low levels of serotonin
affect our mental state, metabolism, and sleep patterns. This wonder hormone helps
to regulate sleep cycles, memory and learning, appetite, mood and behavior, as
well as depression, including seasonal depression.
Melatonin, also known
as the sleep hormone, is a hormone that also affects our sleep cycle and emotional
stability as well. It is synthesized in the pineal gland from serotonin and its
release is stimulated by darkness and lowered lighting levels. The darker our
environment is, the more serotonin is made into melatonin. The hypothalamus of
the brain submits information to the pineal gland based on the light intensity
shining on specialized photorecptors located in the retina of the eye. This information
obtained through bio-chemical reactions determines whether or not more serotonin
should be converted to melatonin.
In the spring and summer months when daylight
hours are longer and we are exposed to more natural lighting our
bodies naturally produce more serotonin. In the fall and winter months due to
the shorter days and less exposure to the intensity of natural light the pineal
gland will change more of the serotonin into melatonin. These decreased levels
of serotonin and increased levels of melatonin bring about the symptoms of seasonal
depression or the winter blues depending on severity.
The symptoms most
common to seasonal affective disorder are:
- Increased sleepiness and difficulty
waking
- Increased appetite and carbohydrate cravings
- Weight gain
- Irritability
- Feelings
of rejection
- Sadness
- Anxiety
- Inability to concentrate
Those
that have serious difficulty getting over the winter blues should seek help from
physicians. Physicians can typically easily diagnose seasonal affective disorder
based on a set of standards developed by the American Psychiatric Association.
The most common seasonal affective disorder treatment is the administration of
light therapy using a SAD lamp that produces 10,000 lux in light intensity. Most
people notice an improvement and relief from seasonal depression symptoms within
2 to 4 days with some individuals taking a few weeks. There are also medications
and other counseling that are sometimes needed in addition if light therapy alone
does not improve the symptoms of seasonal depression.
