seasonal affective disorder
noun /ˌsiːzənl əˈfektɪv dɪsɔːdə(r)/
  /ˌsiːzənl əˈfektɪv dɪsɔːrdər/
 [uncountable] (abbreviation SAD)
- a medical condition in which a person feels sad and tired during late autumn and winter when there is not much light from the sunTopics Illnessc2