Does Harvey Walters' ability to reduce Sanity loss by 1 break the game?
Page 4 on Arkham Horror FAQ from the Fantasy Flight website:


  Q: Does the Strong Mind ability (reduce all Sanity loss 
  by 1) of the professor, Harvey Walters, apply to the casting of spells?
  
  A: No. The professor’s ability works on losses, not costs. 
  The same distinction applies to the gangster, Michael 
  McGlen, and his ability to reduce Stamina losses.