hypnosis vs self-suggestion

hypnosis

noun
  • A trancelike state, artificially induced, in which a person has a heightened suggestibility, and in which suppressed memories may be experienced. 

  • Any of various sleep-like conditions. 

  • The art or skill of hypnotism. 

self-suggestion

noun
  • Synonym of autosuggestion 

How often have the words hypnosis and self-suggestion occurred in a corpus of books? (source: Google Ngram Viewer )