Children who create imaginary companions

  Are children who create imaginary companions psychologically disturbed? What does the research say about this topic? Should you worry if your child has an imaginary friend? http://www.familyresource.com/parenting/character-development/imaginary-friends-should-you-be-concerned http://www.usatoday.com/news/health/2004-12-19-real-play-usat_x.htm http://seattlepi.nwsource.com/lifestyle/202632_imaginary07.html