adolescence vs second childhood

adolescence

noun
  • The transitional period of physical and psychological development between childhood and maturity. 

second childhood

noun
  • A childlike state in any adult, resulting from mental illness, trauma, or other conditions. 

  • The period or state of cognitive decline of an elderly person, characterized by childlike judgment and behavior. 

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