When one becomes depressed as the fun of the holidays comes to an end and everyone has to return to their boring, everyday lives.

Often goes hand-in-hand with christmas tight.
Bob: "What is Steve's problem?"

Sue: "I think he has a severe case of Post-Holiday Depression (PHD). I heard him crying when his co-workers in the next cubicle were talking about their holiday vacations.
by hahaidontgetit December 28, 2010
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