psychiatric vs psychological

psychiatric

adj
  • Of, or relating to, psychiatry. 

psychological

adj
  • Of or pertaining to psychology. 

  • Relating to the mind and behavior or to the mental, emotional, and behavioral characteristics pertaining to a specified person, group, or activity. 

  • Without an objective, or reasonably logical foundation. 

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