Oct. 31 (Bloomberg) -- Shares of Avanir Pharmaceuticals fell the most in seven years after U.S. regulators delayed a decision on whether to approve the company's drug to treat a disorder that often causes unpredictable laughing or crying. The shares fell as much as 46 percent.

The medicine is designed to treat involuntary emotional expression disorder, which can accompany neurological injuries and diseases, including MS...The illness may affect more than 1 million people in the U.S., Avanir said. MORE