Definition of "seasonal affective disorder" []

• A form of depression occurring at certain seasons of the year, especially when the individual has less exposure to sunlight. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Light therapy has been used previously for people with significant seasonal affective disorder as well as nonseasonal depression."