How is SAD different from Major Depressive Disorder or mild depression?
Dr. Rosenthal: SAD is a form of major depressive disorder (MDD); in other words, patients with SAD can be just as depressed as patients with MDD and are often more so. The only distinction between these depressive disorders is the timing of the episodes, which occur during the short, dark days of winter in patients with SAD. Do you think there is a genetic predisposition for SAD? Dr. Rosenthal: There certainly appears to be a genetic predisposition. SAD tends to run in families. Also, there are some genetic variants that appear to be associated with those who have SAD, but this does not explain the cause of SAD symptoms in most sufferers. Are there biological findings that support the distinction between these mood disorders? Dr. Rosenthal: Actually, there are very few direct comparisons between SAD patients and those with other forms of MDD, so we do not know how they differ biologically. Clearly, serotonin and dopamine appear to be involved like other forms of depression. Patients wi
