Major Depressive Disorder with a Seasonal Pattern (formerly known as seasonal affective disorder, or SAD) is characterized by recurrent episodes of depression in late fall and winter, alternating with periods of normal mood the rest of the year. Scientists have identified that the neurotransmitter serotonin may not be working optimally in many people who experience this disorder.

The prevalence of this condition appears to vary with latitude, age and sex:

• Prevalence increases among people living in higher/northern latitudes.
• Younger persons are at higher risk.
• Women are more likely than men to experience this condition.

Symptoms

Although not everyone experiences all the following symptoms, the classic characteristics of Major Depressive Disorder with a Seasonal Pattern include:

• Hypersomnia (or oversleeping)
• Daytime fatigue
• Overeating
• Weight gain
• Craving carbohydrates
• Decreased sexual interest
• Lethargy
• Hopelessness
• Suicidal thoughts
• Lack of interest in usual activities and decreased socialization

Diagnosis

The key to an accurate diagnose of this condition is recognizing its pattern. Symptoms usually begin in October/November and subside in March/April. Some people begin to experience a “slump” as early as August, while others remain well until January. Regardless of the time of onset, most people don’t feel fully “back to normal” until early May.

Treatment

As with most depressive disorders, the best treatment includes a combination of antidepressant medications, cognitive behavioral therapy and exercise. Unlike other depressive disorders, this condition can also be treated with light therapy. Light therapy consists of regular, daily exposure to a “light box,” which artificially simulates high-intensity sunlight. Be aware that ordinary indoor light is not sufficient to treat this condition

Planning Ahead

• Exercise more toward the end of summer
• Get into therapy around September*
• Start your light box in October
• Plan a vacation to a sunny spot in January

*Some people may require treatment only during the time of the year in which they experience symptoms, or they may need treatment that begins before symptoms are most severe. Others may choose year-round treatment.