Seasonal Affective Disorder (SAD) - Symptoms and Causes

What is Seasonal Affective Disorder?

Seasonal affective disorder (SAD) is a type of depression that's related to changes in seasons, usually when falls starts. This seasonal depression gets worse in the late fall or early winter before ending in the sunnier days of spring.

Symptoms

If you have this disorder, you have mood changes and symptoms of depression, including:

• Sadness, feeling depressed most of the day, almost every day.

• Anxiety.

• Carbohydrate cravings and weight gain.

• Extreme fatigue and lack of energy.

• Feelings of hopelessness or worthlessness.

• Trouble concentrating.

• Feeling irritated or agitated.

• Limbs (arms and legs) that feel heavy.

• Loss of interest in usually pleasurable activities, including withdrawing from social activities.

• Sleeping problems (usually oversleeping).

• Thoughts of death or suicide.

People who have summer SAD may experience:

• Agitation and restlessness.

• Anxiety.

• Decreased appetite and weight loss.

• Episodes of violent behavior.

• Trouble sleeping (insomnia).

Causes

The exact cause of Seasonal Affective Disorder is unknown, but theories suggest:

1. Your biological clock change or Circadian Rhythm

In winter, the days are short with less sunlight, and also the nights are long. This may disrupt your body's internal clock and lead to feelings of depression.

2. Drop in Serotonin levels

Serotonin is a brain chemical that affects mood and a drop in its level might play a role in. Reduced sunlight can cause a drop in serotonin that may trigger depression.

3. Imbalance of Melatonin levels

The change in season can disrupt the balance of body's melatonin level, which plays a role in sleep patterns and mood.

4. Vitamin D deficiency

Since sunlight helps produce vitamin D, less sun in the winter can lead to Vitamin D deficiency. This deficiency can affect your serotonin level and your mood.

5. Negative thoughts

People with SAD often have stress, anxiety and negative thoughts about the winter. Researchers aren’t sure if these negative thoughts are a cause or effect of seasonal depression.

Who is at Risk?

Seasonal affective disorder (SAD) is more common in younger people and women. You’re also at higher risk if you:

• Have another mood disorder, such as major depressive disorder or bipolar disorder.

• Have relatives with SAD or other forms of depression or mental health conditions, such as major depression or schizophrenia.

• Live at latitudes far north or far south from the equator. There’s less sunlight during the winter at these latitudes.

• Live in cloudy regions.