Many people go through short periods of time where they feel sad or not like their usual selves. Sometimes, these mood changes begin and end when the seasons change. People may start to feel “down” when the days get shorter and begin to feel better in the spring, with longer daylight hours.  In some cases, these mood changes are more serious and can affect how a person feels, thinks, and handles daily activities. If you have noticed significant changes in your mood and behaviour whenever the seasons change, you may be suffering from seasonal affective disorder (SAD).

What is SAD?

SAD is not considered a separate disorder but is a type of depression characterized by its recurrent seasonal pattern, with symptoms lasting about 4 to 5 months per year. In most cases, Seasonal Affective Disorder symptoms appear during late autumn or early winter and go away during the sunnier days of spring and summer. Occasionally, and less common, are people who present with the opposite pattern; having symptoms that begin in spring or summer and go away during autumn and winter. In either case, symptoms may start out mild and become more severe as the season progresses.

Signs and Symptoms

The signs and symptoms of SAD are those associated with major depression, and some specific symptoms that differ for winter-pattern and summer-pattern SAD. Signs and symptoms of SAD may include:

  • Feeling depressed most of the day, nearly every day
  • Losing interest in activities you once enjoyed
  • Having low energy
  • Having problems with sleeping
  • Experiencing changes in your appetite or weight
  • Feeling sluggish or agitated
  • Having difficulty concentrating
  • Feeling hopeless, worthless or guilty
  • Having frequent thoughts of death or suicide

Symptoms specific to winter-onset SAD, sometimes called winter depression, may include:

  • Oversleeping
  • Appetite changes, especially a craving for foods high in carbohydrates
  • Weight gain
  • Tiredness or low energy

Symptoms specific to summer-onset seasonal affective disorder, sometimes called summer depression, may include:

  • Trouble sleeping (insomnia)
  • Poor appetite
  • Weight loss
  • Agitation or anxiety

In some people with bipolar disorder, spring and summer can bring on symptoms of mania or a less intense form of mania (hypomania), and fall and winter can be a time of depression.

What causes SAD?

Scientists do not fully understand what causes SAD. Research indicates that people with SAD may have reduced activity of the brain chemical (neurotransmitter) serotonin, which helps regulate mood. Research also suggests that sunlight controls the levels of molecules that help maintain normal serotonin levels, but in people with SAD, this regulation does not function properly, resulting in decreased serotonin levels in the winter.

Other findings suggest that people with SAD produce too much melatonin—a hormone that is central for maintaining the normal sleep-wake cycle. Overproduction of melatonin can increase sleepiness.

Both serotonin and melatonin help maintain the body’s daily rhythm that is tied to the seasonal night-day cycle. In people with SAD, the changes in serotonin and melatonin levels disrupt the normal daily rhythms. As a result, they can no longer adjust to the seasonal changes in day length, leading to sleep, mood, and behaviour changes.

Deficits in vitamin D may exacerbate these problems because vitamin D is believed to promote serotonin activity. In addition to vitamin D consumed with diet, the body produces vitamin D when exposed to sunlight on the skin. With less daylight in the winter, people with SAD may have lower vitamin D levels, which may further hinder serotonin activity.

Diagnosis

Seasonal Affective Disorder is diagnosed more often in women than in men. And SAD occurs more frequently in younger adults than in older adults.  Factors that may increase your risk of seasonal affective disorder include:

  • Family history. People with SAD may be more likely to have blood relatives with SAD or another form of depression.
  • Having major depression or bipolar disorder. Symptoms of depression may worsen seasonally if you have one of these conditions.
  • Living far from the equator. SAD appears to be more common among people who live far north or south of the equator. This may be due to decreased sunlight during the winter and longer days during the summer months.

Take signs and symptoms of seasonal affective disorder seriously. As with other types of depression, SAD can get worse and lead to problems if it’s not treated. These can include:

  • Social withdrawal
  • School or work problems
  • Substance abuse
  • Other mental health disorders such as anxiety or eating disorders
  • Suicidal thoughts or behaviour

To be diagnosed with SAD, a person must meet the following criteria:

  • They must have symptoms of major depression or the more specific symptoms listed above.
  • The depressive episodes must occur during specific seasons (i.e., only during the winter months or the summer months) for at least 2 consecutive years. However, not all people with SAD do experience symptoms every year.
  • The episodes must be much more frequent than other depressive episodes that the person may have had at other times of the year during their lifetime.
Treatment

Treatments are available that can help many people with SAD. They fall into four main categories that may be used alone or in combination:

  • Light therapy
  • Psychotherapy
  • Antidepressant medications
  • Vitamin D

So if you think you may be suffering from SAD, come and talk to one of our psychologists about your concerns and commence your road to recovery now.

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