What is SAD?
SAD, Seasonal Affective Disorder, Depression Seasonal Affective Disorder (SAD) is a mood disorder in which people who have normal mental health throughout most of the year experience depressive symptoms typically in the winter, spring or autumn year after year. In the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), SAD is not a unique mood disorder, but is “a specifier of major depression”.
Although experts were initially skeptical, this condition is now recognized as a common disorder, with its prevalence in the U.S. ranging from 1.4% in Florida to 9.7% in New Hampshire. The U.S. National Library of Medicine notes that “some people experience a serious mood change when the seasons change. They may sleep too much, have little energy, and may also feel depressed. Though symptoms can be severe, they usually clear up.” The condition in the summer can include heightened anxiety.
Symptoms of SAD may consist of difficulty waking up in the morning, morning sickness, tendency to oversleep and over eat, especially a craving for carbohydrates, which leads to weight gain. Other symptoms include a lack of energy, difficulty concentrating on or completing tasks, and withdrawal from friends, family, and social activities. This leads to depression, pessimistic feelings of hopelessness, and lack of pleasure which characterize a person suffering from this disorder.
People who experience spring and summer depression show symptoms of classic depression including insomnia, anxiety, irritability, decreased appetite, weight loss and social withdrawal.
According to the American Psychiatric Association DSM-IV criteria, Seasonal Affective Disorder is not regarded as a separate disorder. It is called a “course specifier” and may be applied as an added description to the pattern of major depressive episodes in patients with major depressive disorder or patients with bipolar disorder. The “Seasonal Pattern Specifier” must meet four criteria: depressive episodes at a particular time of the year; remissions or mania/hypomania at a characteristic time of year; these patterns must have lasted two years with no nonseasonal major depressive episodes during that same period; and these seasonal depressive episodes outnumber other depressive episodes throughout the patient’s lifetime.
The Mayo Clinic describes three types of SAD, each with its own set of symptoms. In the popular culture, sometimes the term “seasonal affective disorder” is applied inaccurately to the normal shift to lower energy levels in winter, leading people to believe they have a physical problem that should be addressed with various therapies or drugs.
Seasonal mood variations are believed to be related to light. An argument for this view is the effectiveness of bright-light therapy. The symptoms of SAD mimic those of mild chronic depression or even major depressive disorder.
At times, patients may not feel depressed, but rather lack energy to perform everyday activities. One possibility is that SAD is related to a lack of serotonin. Another theory is that the cause may be related to melatonin which is produced in dim light and darkness by the pineal gland since there are direct connections between the retina and the pineal gland.
Subsyndromal Seasonal Affective Disorder is a milder form of SAD experienced by an estimated 14.3% (vs. 6.1% SAD) of the U.S. population. The blue feeling experienced by both SAD and SSAD sufferers can usually be dampened or extinguished by exercise and increased outdoor activity, particularly on sunny days, resulting in increased solar exposure. Connections between human mood, as well as energy levels, and the seasons are well documented, even in healthy individuals.
There are many different treatments for classic (winter-based) seasonal affective disorder. Light therapy uses a lightbox which emits far more lumens than a customary incandescent lamp. Bright white “full spectrum” light at 10,000 lux, blue light at a wavelength of 480 nm at 2,500 lux or green (actually cyan or blue-green) light at a wavelength of 500 nm at 350 lux are used with the first-mentioned historically preferred.
Bright light therapy is effective with the patient sitting a prescribed distance, commonly 30–60 cm, in front of the box with her/his eyes open but not staring at the light source for 30–60 minutes. Discovering the best schedule is essential. Patients using light therapy can experience improvement during the first week, but increased results are evident when continued throughout several weeks. Most studies have found it effective without use year round but rather as a seasonal treatment lasting for several weeks until frequent light exposure is naturally obtained.
Light therapy has been used for over 20 years to treat SAD with numerous studies citing its effectiveness. It is recommended as a first-line treatment for SAD in Canadian, American, and international clinical guidelines. The mood of individuals with SAD can improve with as little as 20 minutes of bright light exposure. Bright light is more effective than dim light in protecting against “mood lowering” which commonly occurs in SAD.
According to researchers, Seasonal Affective Disorder or SAD, affects up to twenty percent of the population.
Common symptoms of SAD are tiredness, sleeping more often, carbohydrate cravings and sadness or depression. During winter seasons, chemicals in the brain produce higher levels of melatonin, which in turn makes people feel more lethargic. Serotonin levels, which help regulate people’s moods, are lower in the winter months.
There are several treatment options for SAD. However, many experts highly recommend light therapy using a SAD light therapy unit. These light boxes provide 10,000 lux of illumination (10-25 times brighter than ordinary light) which act as forty minutes of outdoor sunlight.
Download our brochure to see the variety of SAD light offered by Daavlin.
- Seasonal Affective Disorder at the Open Directory Project
Frequently Asked Questions
What are winter blues and seasonal affective disorder (SAD)?
Winter blues refers to a set of symptoms many people get in the short daylight months- typically September to March- including sadness, fatigue, decreased libido, difficulty concentrating, irritability, increased sleep and appetite, carbohydrate craving and weight gain. SAD is the severe form of winter blues, so that you become clinically depressed and the other symptoms become seriously debilitating. A key feature is that symptoms appear as daylight decreases in the fall and disappear as daylight increases in the spring.
How common are winter blues and SAD?
As one might expect, winter blues and SAD are more common as you move further from the equator. Winter days are shorter and daylight decreases as you move toward the North or South Poles. Perhaps 25% of people in the northern US & Canada suffer from winter blues, with about 15-30% of these having SAD. People living in lower latitudes may also experience winter blues if they spend their days in offices that are typically much less bright than the outdoors, or if their winter weather is cloudy.
What is a circadian rhythm?
We all have an internal clock that determines our wake/sleep cycle, or circadian rhythm. This circadian rhythm normally matches our day/night cycle, but may be disrupted by jet travel across time zones, work shift changes (day shift to night shift and back again), or some insomnias where our sleep phase gets “out of sync”. When you circadian rhythm is disrupted, you suffer fatigue, decreased concentration and productivity, and increased work errors.
What is light therapy?
Light therapy is the shining of bright light into your eyes-typically for a half hour each session. Since the 1980’s, light therapy has become the first line treatment for winter blues and SAD. Bright light can also be used to shift your circadian (wake/sleep) cycle, so it is used to prevent jet lag, minimize work shift change fatigue, and help abnormal sleep phase insomnias.
How does light therapy work?
We know that shining bright light into your eyes:
- a) suppresses brain melatonin, causing wakefulness, and
- b) enhances brain serotonin, causing mood elevation.
Light therapy takes advantage of these effects to alter your circadian rhythm to prevent jet lag and work shift change fatigue and some insomnias, as well as to treat winter blues and SAD.
How much light is best?
Light therapy is measured in lux, which is measured of the intensity of light as perceived by our eyes. Typical room light intensity is several hundred lux. Light therapy began years ago with what we now consider to be low doses-500-2500 lux- for 1-2hours. Studies showed that treatment times can be reduced by increasing the light dose. Now, 10,000 lux for ½ hour is considered by many to be a standard dose. The Feel Bright Light brackets this “standard dose” by providing 8,000 or 12,000 lux so you can adjust to surrounding light conditions while receiving a very effective dose.
How can I compare light doses between different devices?
Each device manufacturer publishes the intensity of their device (usually in lux) as measured at the recommended distance from your eyes. So, the lux from a portable device that is 1-2 inches from your eyes is comparable to the lux of a desk-top device that is 18 inches from your eyes, etc.
What time of day is best?
For winter blues, a bright light session shortly after arising in the morning works best for most people. Some people benefit from an additional session in the late afternoon. Bright light use in the evening may disrupt your sleep pattern. For circadian rhythm shifting, i.e. jet lag, shift work, and sleep phase insomnias, the time of day to use bright light depends on whether you want to shift your circadian clock forward or backward.
What type of lamp is best?
The best lamp provides:
- high intensity;
- maximum blue-to-green spectrum;
- focused light to make the best use of the available light;
- long life;
- small power requirement.
Should I use light?
Reasons to consider bright light:
Most people with winter blues are likely to respond well to light. If your symptoms are severe, you may suffer from SAD. Light therapy may work well for you, but you should consult with your clinician before choosing any therapy. Bright light can be used along with other treatments- e.g., antidepressants for SAD. Likewise, most people will respond to light for circadian rhythm adjustment- i.e., jet lag, shift change work, and some insomnias.
Reasons to not use light:
Generally, bright light is very safe. If you:
- a) have any eye disorder (e.g., cataracts, glaucoma, retinal disease),
- b) have any disease with high risk for eye problems (e.g., diabetes, lupus),
- c) have any problem triggered by bright light (e.g., migraine),
- d) take photosensitizing medication (e.g., certain psychiatric drugs, melatonin), you should consult your clinician prior to starting bright light sessions.
Should I look directly at the light?
No. You should let the light be in your peripheral vision field- preferably above your line of sight, so the bright light hits your lower retina for the best effect. Some clinicians recommend occasional looks directly at the light for brief periods.
Can I get light therapy with my eyes closed?
The positive effects of most light therapy studies have been done with the eyes open. The standard 10,000 lux for ½ hour session assumes your eyes are open.
Does light cause side-effects?
Reported side effects from bright light are generally uncommon and mild. They include:
- a) nausea-which tends to pass quickly as light is continued
- b) headache, eye strain, agitation, insomnia-which is usually controlled by decreasing the light dose or altering the time of day that the light is used.
Will bright light hurt my eyes?
Bright light at 10,000 lux is within the range of light we experience almost every day- from a dimly lit room of 100 lux to a sunny day outside of 40,000 lux. Eye exams of subjects receiving up to 20,000 lux have revealed no risks. Bright lights may cause some people to “see spots” for a short period after use. These “spots” normally disappear within a few minutes. Elderly people may take longer-up to 10 minutes-to return to normal.
What research has been done?
Many studies have been done over the years that yield information about various aspects of phototherapy. Light effectiveness for winter blues and circadian rhythm shifting is well established.
In addition, research is now looking at using light for:
- non-seasonal depression
- post-partum depression
- pre-menstrual syndrome
- chronic fatigue syndrome
- ADD, ADHD
- sustained wakefulness
- substance abuse
Are lights medically approved and reimbursed?
Although clinicians increasingly understand and prescribe light therapy, there is, as yet, no light device that has completed the FDA process. Since light therapy is relatively new, insurance coverage is spotty. A claim may be initially rejected, but upon further explanation, may be covered. Medicare does not routinely cover such devices. Expect coverage for SAD to improve as insurance companies learn that light therapy is far less expensive than antidepressants.
Should I use a portable or a desk-top device?
Most desk-top devices provide 10,000 lux and are effective. If you can sit in one place for a half-hour each morning, a desk-top device may work well for you. However, you may find it much more convenient to do your normal daily activities while receiving your bright light sessions. A portable device may be the only way to achieve your goals and stay with a light program. Many people own both a desk-top and a portable device, and they use either under different circumstances.
How soon should I feel better after using lights?
The effect of light is prompt-hours to days, generally not weeks or months. For jet lag and shift change fatigue, the light is used to prevent symptoms before they actually occur.
How long will I need to use the lights?
- For winter blues, most people use the lights daily each winter until the symptoms abate as days lengthen-typically in March or April.
- For jet lag, the bright lights are used prior to the trip
- For shift change fatigue, the lights are used prior to changing shifts.
- For sleep phase insomnias, the problem may be long-term for the elderly, but teens tend to “grow out of it”
Can I drive my car while using the Feel Bright Light?
No. The Light may be safely used while doing many daily activities, but should not be used while driving or operating equipment. Depending upon the background light, it may be difficult to see well beyond the lights mounted on your visor.