despair vs dysthymia

despair

noun
  • That which causes despair. 

  • Loss of hope; utter hopelessness; complete despondency. 

  • That which is despaired of. 

verb
  • To be hopeless; to have no hope; to give up all hope or expectation. 

  • To cause to despair. 

dysthymia

noun
  • A tendency to be depressed, without hope. 

  • A form of clinical depression, characterized by low-grade depression which lasts at least 2 years. 

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