dysphoria vs nightmare

dysphoria

noun
  • A state of feeling unwell or unhappy; a feeling of emotional and mental discomfort and suffering from restlessness, malaise, depression or anxiety. 

nightmare

noun
  • Any bad, miserable, difficult or terrifying situation or experience that arouses anxiety, terror, agony or great displeasure. 

  • A very bad or frightening dream. 

  • A feeling of extreme anxiety or suffocation experienced during sleep; Sleep paralysis. 

verb
  • To have a nightmare. 

How often have the words dysphoria and nightmare occurred in a corpus of books? (source: Google Ngram Viewer )