Seasonal affective disorder is a mood disorder, in which symptoms of depression set in during specific seasons of the year. Most people afflicted with the condition become symptomatic during the winter months, but the condition can manifest during the spring, summer or autumn as well. Patients with seasonal affective disorder report normal mood stability and mental health during the other months of the year. Symptoms include prolonged periods of low mood, lack of energy and hypersomnia. Those with summertime seasonal affective disorder may also develop anxiety. Light therapy, cognitive-behavior therapy (CBT), melatonin supplements and antidepressants may be used to treat the condition.