How to Know If You Have Seasonal Affective Disorder (Plus How to Treat It) Seasonal affective disorder, or SAD, is a subset of depression that is more severe in the winter months. Symptoms include feeling hopeless and sluggish, withdrawing socially, and not getting pleasure from activities you normally enjoy. To be formally diagnosed with SAD, you need to see these symptoms during the same time of year for a couple of years. If you think you have SAD, visit a mental health specialist to get properly diagnosed and started on treatment. The first course of treatment is usually to go outside and spend more time in the sunlight. Exercising also helps battle symptoms of SAD. Improving your eating habits and taking vitamin D supplements should also help ease your SAD symptoms. A seasonal affective disorder lamp can help increase productivity and decrease the melatonin that is making you feel tired.