At one time, a person could not recover mental distress unless there was a tort associated with the mental distress.  However, there is now a separate tort for intentionally causing mental distress.  This tort arises when a defendant purposely subjects a plaintiff to unnecessary emotional distress.  Outrageous conduct must generally be present.  For example, if a person bawls someone out in public with the intent to humiliate the person, this could possibly be the tort of intentional infliction of mental distress.  Damages must be proven, however.  A collection agency who uses harassing techniques to collect a debt could possibly be held liable for committing this tort.