delirium vs dithers

delirium

noun
  • Wild, frenzied excitement or ecstasy. 

  • A temporary mental state with a sudden onset, usually reversible, including symptoms of confusion, inability to concentrate, disorientation, anxiety, and sometimes hallucinations. Causes can include dehydration, drug intoxication, and severe infection. 

dithers

noun
  • The creeps; a feeling of fear or anxiety. 

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