TAE: Seasonal Affective Disorder – Symptoms, Causes, Diagnosis and Treatment


They are known in their acronym in English as SAD (Seasonal Affective Disorder). It is a disorder related to changes in seasons; the TAE (for its acronym in Spanish) begins and ends at approximately the same time every year; some people with this disorder begin to perceive the symptoms in the fall and continue in the winter months.

This type of depression can occur less frequently in the spring or early summer. Treatment for SAD may include light therapy (phototherapy), psychotherapy, and medications.

Symptoms of seasonal affective disorder

In most cases, symptoms arise during late fall or early winter and fade during the warm days of spring and summer.

However, some individuals have an opposite pattern with symptoms that begin in spring or summer. In either case, the symptoms start moderately and increase as the season progresses.

Major depression

The seasonal affective disorder is a subtype of major depression that comes and goes as a function of the seasons. So the symptoms of major depression can be:

  • Feeling depressed most of the day, almost every day.
  • Feeling hopeless or worthless.
  • Have low energy consumption.
  • Loss of interest in daily activities.
  • Problems with sleep.
  • Experience changes in appetite or weight.
  • Feeling weak or agitated
  • Difficult to focus.
  • Suicidal thoughts.

Autumn and winter TAE

The specific symptoms of depression, sometimes called Seasonal Affective Disorder, begin in the winter:


  • Irritability.
  • Tiredness or lack of energy
  • Problems relating to other people.
  • Hypersensitivity to rejection.
  • Changes in appetite.
  • Weight gain.

Spring and summer

The specific symptoms of seasonal affective summer disorder may include:

  • Depression.
  • Insomnia.
  • Weightloss.
  • Loss of appetite
  • Agitation or anxiety

Seasonal changes in bipolar disorder

In people with bipolar disorder, the spring and summer seasons cause mild mania (hypomania) symptoms, while autumn and winter cause them a moment of depression.


The biological clock (circadian rhythm). The reduced level of sunlight in autumn and winter can cause symptoms of SAD in the winter. This decrease in sunlight can alter the body’s internal clock and lead to feelings of depression.

Serotonin levels A decrease in serotonin – a chemical substance in the brain that disturbs mood – could be one of the leading causes of seasonal affective disorder. Low exposure to sunlight can cause a decrease in serotonin and cause depression.

Melatonin levels. The change of season can disturb the balance of the body level of melatonin, which plays a vital role in sleep patterns and mood.

Tests and diagnosis

Physical exam.

Laboratory tests. For example, a blood test called a complete blood count (CBC) or thyroid test.

Psychological evaluation. To check for signs of depression.

Seasonal affective disorder is considered a subtype of major depression or bipolar disorder. Even conducting a thorough evaluation can be challenging to diagnose SAD because other types of depression or other mental health problems can cause similar symptoms.

Treatment of the TAE

The seasonal affective disorder can be treated with light therapy, medications, and psychotherapy. Both treatments can potentially trigger a manic episode.

Light therapy

Also called phototherapy, it is based on sitting the person a few feet away from a bright lightbox. Light therapy mimics natural light outdoors and causes a change in brain chemicals related to mood.

Light therapy is one of the most used treatments for SAD symptoms started in the fall. It usually starts working in a few days to two weeks and causes few side effects. Research on light therapy is limited but seems to work for most people to relieve symptoms.


The antidepressant bupropion (Wellbutrin XL, Aplenzin) helps prevent depressive episodes in people with a history of this disorder. Other common antidepressants can also be used to treat this disorder.

The doctor may recommend starting treatment with an antidepressant before its symptoms typically begin each year. It is important to remember that it may take several weeks to notice the full benefits of an antidepressant.


Also called conversation therapy, it is another option to treat the seasonal affective disorder. It can help:

  • Identify and change negative thoughts and behaviors.
  • Learn healthy ways to deal with the disease.
  • Learn to control stress.