It was first developed by American psychiatrist Norman E. Rosenthal and his National Institute of Mental Health colleagues in 1984, and continues to be widely used.
[2] The questionnaire asks subjects to score the amounts of seasonal changes they have experienced in sleep, socialization, mood, weight, appetite and energy.
[3] Subjects are often taught how to interpret their scores, and cautioned that a self-assessment can never substitute for a clinical evaluation.
It has also been found to have low specificity (in that people who have other forms of depression can score as if they have SAD).
This is true because of its early development, historically wide dissemination, and the absence of better-validated alternatives.