What Is Seasonal Affective Disorder?

Medically reviewed by Bavani Rajah, MD, Child and Adolescent Psychiatry Fellow at Lurie Children's.

It's common for many individuals to experience "the winter blues" during the cold, dark months of the year but then feel better during the spring, with longer daylight hours. However, some individuals experience more serious symptoms that can affect how they feel, think and handle daily activities. This type of depression is called Seasonal Affective Disorder (SAD) and is characterized by its recurrent seasonal pattern, with symptoms lasting 4 to 5 months per year.

Signs & Symptoms of Seasonal Affective Disorder

Many signs and symptoms of Seasonal Affective Disorder include those associated with major depression, as well as some specific symptoms that differ for winter-pattern and summer-pattern SAD, including: 

• Depressed or irritable mood 
• Lack of energy and motivation 
• Losing interest in previously enjoyed activities 
• Difficulty with sleep or appetite 
• Feelings of isolation and withdrawal from social activities 
• Feelings of hopelessness and helplessness 
• Suicidal thinking*

*If you or someone you know is experiencing suicidal thinking, help is available immediately. The National Suicide and Crisis Line operates 24 hours a day, 7 days a week. Call or text 988 for immediate assistance*

For winter-pattern SAD, additional specific symptoms may include:

• Oversleeping (hypersomnia)
• Overeating, particularly with a craving for carbohydrates
• Weight gain
• Social withdrawal (feeling like “hibernating”)

Specific symptoms for summer-pattern SAD may include:

• Trouble sleeping (insomnia)
• Poor appetite, leading to weight loss
• Restlessness and agitation
• Anxiety
• Episodes of violent behavior

What Causes Seasonal Affective Disorder? 

SAD is a type of depression typically triggered by changes in seasons. During late fall and winter, the amount of light and sunshine our bodies receive drastically changes, which can cause individuals to experience a “circadian rhythms” or sleep-wake cycle. Experiencing periods of feeling sad, low and even unmotivated to leave the house during winter is common, but what makes a diagnosis like Seasonal Affective Disorder different is the length of time and impact it has on an individual’s life. 

Seasonal Affective Disorder Treatment 

There are many treatments that can be used alone or in combination to treat SAD, including medications, light therapy and psychotherapy. If you or someone you know is experiencing symptoms of Seasonal Affective Disorder, help is out there! Talk to your primary care provider or seek help from a mental health professional to determine what type of treatment is best for you.