While cutesy terms like the “winter blues” might make it seem like SAD is no big deal, quite the opposite is true. The symptoms can be distressing and overwhelming and can have an immense impact on a patient’s ability to function normally.

Signs and symptoms of seasonal affective disorder may include:

• Feeling down or depressed most of the day, nearly every day
• Loss of interest in the activities you enjoy
• Low energy
• Trouble sleeping
• Changes in appetite or weight
• Feeling sluggish or agitated
• Difficulty concentrating
• Feeling hopeless, worthless or guilty
• Frequent thoughts of death or suicide
• Avoiding things that trigger anxiety

Because SAD symptoms come and go, it can be tempting to just tough it out until things get better, but it’s important to take SAD seriously and seek diagnosis when symptoms occur consistently.

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) for at least 2 consecutive years.
• 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.

For anyone who thinks they have seasonal affective disorder, a primary care provider is a great first stop so they can rule out other conditions that might cause similar symptoms. SAD can be misdiagnosed in the presence of conditions like hypothyroidism, hypoglycemia, infectious mononucleosis, and other viral infections, so proper evaluation is key.

While the specific cause of seasonal affective disorder remains unknown, SAD has been linked to a biochemical imbalance in the brain that’s prompted by fewer daylight hours and reduced sunlight in winter. As seasons change, people experience a shift in their biological internal clock, which can throw their schedule out of whack and lead to feelings of depression. This change can also disrupt the balance of the body’s level of melatonin, which plays a role in sleep patterns and mood. Reduced sunlight exposure can also cause a drop in serotonin, which also affects mood.

Factors that may increase your risk of seasonal affective disorder include:

• Age: SAD may begin at any age, but it’s more common in younger people and typically starts between ages 18 and 30.
• Gender: SAD is diagnosed more frequently in women than in men, with about 75% of people diagnosed with SAD being female.
• 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, likely due to decreased sunlight during the winter and longer days during the summer months.

In addition to getting regular exercise, eating healthy, getting enough sleep, staying active, and being socially connected, increased exposure to sunlight can help reduce risk or symptoms of seasonal affective disorder. Just be sure to put sunscreen on (even in the winter) to protect against skin cancer.

With the right treatment, SAD can be a manageable condition, but just like other types of depression, SAD can get worse if it’s not treated. This can lead to complications like social withdrawal, problems at school or work, substance abuse, other mental health disorders, or suicidal thoughts or behavior. Once a diagnosis is confirmed, a mental health professional can discuss one of the below treatment options:

• Light therapy involves sitting in front of a light therapy box that emits a very bright light and filters out harmful ultraviolet (UV) rays). It usually requires 20 minutes or more of exposure per day to be effective. Most people see some improvements from light therapy within 1-2 weeks of beginning treatment. Treatment is usually continued through the winter to prevent relapse. Some people may even begin light therapy in early fall to prevent symptoms.
• Talk therapy, particularly cognitive behavior therapy (CBT), can effectively treat SAD.‍
• Selective serotonin reuptake inhibitors (SSRIs) are the type of antidepressant most commonly used to treat SAD.