Symptoms often include: debilitating boredom; smiling (usually at the host or hostess) against one's will or when unhappy; anxiety; loss of interest in life, food, and socializing; rage; and social anxiety.
DPS can be cured or prevented with the end of the dinner party, a good book, enjoyable music, or speaking with someone that isn't mind-numbingly boring.
Jack: She said it was boring and she didn't want to suffer from Dinner Party Syndrome.
Mother: Why don't you want to go to the dinner party tonight?
Daughter: Because only your friends will be there and I hate them. If I go, I'll have an intense case of Dinner Party Syndrome.