(HealthDay News) -- Seasonal affective disorder (SAD) is characterized by a series of mood changes that appear year after year as the seasons change -- most often as the weather gets colder.

The American Academy of Family Physicians says symptoms of SAD often include:

• A sudden craving for sweet or starchy foods, changes in appetite or gaining weight.
• Lack of energy, feeling tired or sleeping more than usual.
• Anxiety, irritability or having difficulty concentrating.
• Unusual sensitivity to social rejection.
• Feeling guilty or hopeless.