[…] Although there are no official statistics, some experts believe that as many as one in seven people experience some level of coulrophobia, as fear of clowns is clinically known. Symptoms can include shortness of breath, irregular heartbeat, sweating, nausea and overall feelings of dread.

[from:“Fear of Clowns: No Laughing Matter“ by Alex Waterfield (Columbia News Service; 01/2006) / source: http://www.insnews.org/health/focus/2006/01/clown.fear.htm]