A patient who changed my practice: Herb Kern, the first light therapy patient

This paper presents the case of Herb Kern, the first patient with clear-cut seasonal mood cycles in whom light therapy was used to reverse depression. His successful treatment was an inspiration to the author to define the syndrome of Seasonal Affective Disorder (SAD) and use light therapy as a systematic controlled treatment for this condition. This is an example of how a single patient can lead to the recognition of a common condition and a novel treatment modality.