Seasonal Affective Disorder – Causes, Symptoms, and Treatments.


Seasonal affective disorder (SAD), formally referred to as recurrent depression with seasonal pattern, is a type of depression that tends to occur (and recur) as the days grow shorter in the fall and winter. It is believed that affected people react adversely to the decreasing amounts of sunlight and the colder temperatures as the fall and winter progress. It is important to note that although seasonal affective disorder usually presents in the fall and winter there are those who suffer from this condition during the summer instead of, or in addition to, during the fall or winter.

Seasonal Affective Disorder


SAD was first systematically reported and named in the early 1980s by Norman E. Rosenthal, M.D., and his associates at the National Institute of Mental Health (NIMH). Rosenthal was initially motivated by his desire to discover the cause of his own experience of depression during the dark days of the northern US winter. He theorized that the reduction in available natural light during winter was the cause. Rosenthal and his colleagues then documented the phenomenon of SAD in a placebo-controlled study utilizing light therapy. A paper based on this research was published in 1984. Although Rosenthal’s ideas were initially greeted with skepticism, SAD has become well recognized, and his 1993 book, Winter Blues has become the standard introduction to the subject.

Research on SAD in the United States began in 1979 when Herb Kern, a research engineer, had also noticed that he felt depressed during the winter months. Kern suspected that scarcer light in winter was the cause and discussed the idea with scientists at the NIMH who were working on bodily rhythms. They were intrigued, and responded by devising a lightbox to treat Kern’s depression. Kern felt much better within a few days of treatments, as did other patients treated in the same way. It has been also suggested that SAD affects risky behavior, and those affected by SAD are more likely to opt for conservative investments, whether financially or scientifically.


SAD is considered to be a relatively common disorder. The prevalence of SAD tends to vary across populations. The prevalence of SAD appears to be most linked to photoperiod and as such tends to be more prevalent with higher latitudes, though the evidence is not equivocal. In the United States, prevalence estimates range from 0.4% to as high as 10% depending on the methodology being used.  There is significant evidence that people who migrate from lower to higher altitudes are more susceptible to SAD.  SAD seems to affect women more commonly than men (4:1 ratio) and appears to decrease in prevalence with age.

Winter-onset SAD is more common (often characterized by atypical depressive symptoms including; hypersomnia, increased appetite, and craving for carbohydrates). On the other hand, spring/summer also seen and is more frequently associated with insomnia and loss of appetite.

Risk factors

Some people have a higher risk for developing Seasonal Affective disorder (SAD) than others.

  • Certain medications/drugs can also aggravate or increase the risk of of SAD.
  • Warning – You must not reduce medications unless you have first agreed this with your doctor!
  • The following drugs/medicines may aggravate or increase the risk of SAD:
  • A recent case study reported in a psychiatry journal suggests that there may be a link between varenicilline (a nicotine substitute used for giving up smoking) and exacerbation of recurrent depression.
  • Melatonin is sometimes used for insomnia or as a pre-med before surgery and this could aggravate SAD. A small study demonstrated that melatonin exacerbated depression in moderately to severely depressed patients.  Melatonin should also not be used alongside light therapy as it will interact with the secretion time of melatonin in the brain that is the achieved with the Light therapy.
  • Caffeine interacts with melatonin and may disrupt sleep patterns.

The following studies have shown evidence that some people have a higher risk of developing seasonal affective disorder:


  • The cause for SAD is unknown. One theory is that it is related to the amount of melatonin in the body, a hormone secreted by the pineal gland. Darkness increases the body’s production of melatonin, which regulates sleep. As the winter days get shorter and darker, melatonin production in the body increases and people tend to feel sleepier and more lethargic.
  • Another theory is that people with SAD may have trouble regulating their levels of serotonin, which is a major neurotransmitter involved in mood. Finally, research has suggested that people with SAD also may produce less Vitamin D, which is believed to play a role in serotonin activity. Vitamin D insufficiency may be associated with clinically significant depression symptoms.
  • There are several known risk factors that increase an individual’s chance of developing SAD. For example, SAD is more frequent in people who live far north or south of the equator. Additionally, people with a family history of other types of depression are more likely to develop SAD than people who do not have this family history.

Symptoms of seasonal affective disorder

SAD has many different symptoms. You do not need all of them to be experiencing SAD. If a doctor gives you a diagnosis of SAD, it is likely to be because you have been experiencing a number of these symptoms in the same season for at least two or three years:

  • Lack of energy for everyday tasks, such as studying or going to work
  • Concentration problems
  • Sleep problems – such as sleeping for longer than usual or not being able to get to sleep
  • Depression – feeling sad, low, tearful, guilty, like you have let others or yourself down; sometimes feeling hopeless and despairing, sometimes apathetic and feeling nothing
  • Anxiety – tenseness and inability to cope with everyday stresses
  • Panic attacks
  • Mood changes – in some people, bursts of hyperactivity and cheerfulness (known as hypomania) in spring and autumn
  • Overeating – particularly ‘comfort eating’ or snacking more than usual
  • Being more prone to illness – some people with SAD may have a lowered immune system during the winter, and may be more likely to get colds, infections and other illnesses
  • Loss of interest in sex or physical contact
  • Social and relationship problems – irritability or not wanting to see people; difficult or abusive behaviour
  • Greater drug or alcohol use

Diagnosis and test

To help diagnose seasonal affective disorder, your doctor or mental health provider may do a thorough evaluation, which generally includes:

Physical exam: Your doctor may do a physical exam and ask in-depth questions about your health. In some cases, depression may be linked to an underlying physical health problem.

Lab tests: For example, your doctor may do a blood test called a complete blood count (CBC) or test your thyroid to make sure it’s functioning properly.

Psychological evaluation: To check for signs of depression, your doctor or mental health provider asks about your symptoms, thoughts, feelings and behavior patterns. Your doctor may have you fill out a questionnaire to help answer these questions.

Seasonal affective disorder is considered a subtype of major depression or bipolar disorder. Even with a thorough evaluation, it can sometimes be difficult for your doctor or mental health provider to diagnose SAD because other types of depression or other mental health conditions can cause similar symptoms.

Many mental health professionals use the criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association, to diagnose mental conditions. This manual is also used by insurance companies to reimburse for treatment.

The DSM-5 criteria for diagnosing depression with a seasonal pattern includes having these experiences for at least the last two years:

  • Depression that begins during a specific season every year
  • Depression that ends during a specific season every year
  • No episodes of depression during the season in which you experience a normal mood
  • Many more seasons of depression than seasons without depression over the lifetime of your illness

Treatment and medications

With any mental health problem, there is no one-size-fits-all treatment. Here are a few options to explore with your doctor.

Medication:  Antidepressants have proven to be effective for people with SAD, especially those with intense symptoms. Medication requires patience, because it can take several weeks before you begin to feel the effects. It’s also important not to stop taking the medication if you feel better. Consult with your doctor before you change your dosage, and let him or her know if you experience any side effects.

Psychotherapy : Talk therapy can be an invaluable option for those with SAD. A psychotherapist can help you identify patterns in negative thinking and behavior that impact depression, learn positive ways of coping with symptoms, and institute relaxation techniques that can help you restore lost energy.

Light therapy: Phototherapy involves exposing oneself to light via a special box or lamp. This device produces similar effects to natural light, triggering chemicals in your brain that help regulate your mood. This treatment has proven effective especially for those who experience the winter version of SAD. Don’t make an impulse buy on the Internet though, as it’s important to consult with your doctor first. You want to make sure you’ve purchased an effective and safe device.

Complications of seasonal affective disorder

  • Depression is often chronic, with episodes of recurrence and improvement. About a third of patients with a single episode of major depression will have another episode within 1 year after discontinuing treatment, and more than half will have a recurrence at some point in their lives.
  • Depression is more likely to recur if the first episode was severe or prolonged, or if there have been prior recurrences. To date, even newer antidepressants have failed to achieve permanent remission in many patients with major depression, although the standard medications are very effective in treating and preventing acute episodes.

Coping and support

These steps can help you manage seasonal affective disorder:

  • Stick to your treatment plan. Take medications as directed and attend therapy appointments as scheduled.
  • Take care of yourself. Get enough rest and take time to relax. Participate in an exercise program or engage in another form of regular physical activity. Make healthy choices for meals and snacks. Don’t turn to alcohol or illegal drugs for relief.
  • Practice stress management. Learn techniques to manage your stress better. Unmanaged stress can lead to depression, overeating, or other unhealthy thoughts and behaviors.
  • When you’re feeling down, it can be hard to be social. Make an effort to connect with people you enjoy being around. They can offer support, a shoulder to cry on or a joke to give you a little boost.
  • Take a trip. If possible, take winter vacations in sunny, warm locations if you have winter SAD or to cooler locations if you have summer SAD.

Prevention of seasonal affective disorder

  • There’s no known way to prevent the development of seasonal affective disorder. However, if you take steps early on to manage symptoms, you may be able to prevent them from getting worse over time.
  • Some people find it helpful to begin treatment before symptoms would normally start in the fall or winter, and then continue treatment past the time symptoms would normally go away. Other people need continuous treatment to prevent symptoms from returning.
  • If you can get control of your symptoms before they get worse, you may be able to head off serious changes in mood, appetite and energy levels.


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  1. I hv same symptoms mentioned above there with addition body burning, gas n breathing problem….immediate i need to take Felis S Plus….but if there is any better medicine…please suggest.

  2. blood test name of anxiety disorder panic attect ?

    • Blood tests to check electrolytes, liver function, toxicology screening, and kidney function. Because the kidneys and liver are responsible for the elimination of depression medications, impairment to either of these two organs may cause the drugs to accumulate in the body.

  3. I’m suffering panic attack and anxiety disorder,, I’m taking treatment last 3 years but it’s not controlling fully.. Some times I feel better sometimes very sad… Wt will I do now

  4. I want to now the effects of antidepressants accumulation in the body as bcause of kidney en liver failure

    • nausea
      increased appetite and weight gain
      loss of sexual desire and other sexual problems, such as erectile dysfunction and decreased orgasm
      fatigue and drowsiness
      dry mouth
      blurred vision

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