Seasonal depression is also known as seasonal affective disorder, or SAD. It is a form of depression that is associated with the change in seasons and occurs at the same time every year. Most people who suffer from seasonal affective disorder being to experience symptoms in the fall and continue experiencing them throughout the winter. However, there are some people who get seasonal affective disorder in the spring or summer. About six percent of the population in the United States is affected by seasonal affective disorder. In addition, another 14 percent of adults in the United States suffer from a form of seasonal affective disorder that is milder.

Seasonal affective disorder is a type of major depression. Because of this, some of the symptoms of seasonal affective disorder may be some of the same symptoms seen with major depression. This includes feeling depressed most of the day, nearly every day, feeling hopeless or worthless, having low energy, losing interest in activities you once enjoyed, having problems with sleeping, experiencing changes in your appetite or weight, feeling sluggish or agitated, having difficulty concentrating, or having frequent thoughts of death or suicide.

Symptoms of seasonal affective disorder that occurs during the fall and winter include irritability, tiredness or low energy, problems getting along with other people, hypersensitivity to rejection, heavy feeling in the arms or legs, oversleeping, appetite changes (especially a craving for foods high in carbohydrates), or weight gain.

Symptoms of seasonal affective disorder that occurs in the spring and summer include depression, trouble sleeping (i.e. insomnia), weight loss, poor appetite, agitation or anxiety.

The risk factors that increase your risk of developing seasonal affective disorder include:

·         Being female. It is more common for women to be affected by SAD than men. However, men may have more-severe symptoms.

·         Age. Young people have a higher risk of winter SAD, and winter SAD is less likely to occur in older adults.

·         Family history. You are at a higher risk for developing SAD if you have a family member who has had SAD or another form of depression.

·         Having clinical depression or bipolar disorder. Symptoms of depression may worsen seasonally if you have one of these conditions.

·         Living far from the equator. It is more common for people to develop SAD in areas that are located further from the equator. This may be due to the fact that there is less sunlight during the winter and longer days during the summer months.​