A reader asks:

 Does SAD typically get more severe over the years? Is it common to have anxiety with it?

Answer:

Many, but not all, SAD patients report worsening over the years, at least through middle age. SAD seems to be less of a problem during old age. We’re not sure why, but it could be that the depression becomes more chronic. Anxiety, tenseness and irritability are common in SAD, as they are in other types of depression. On the other hand, many SAD patients report being lethargic, apathetic and “vegged out,” rather than anxious. Although anxiety per se is not a defining characteristic of SAD, it improves as mood lifts with successful treatment.