In their search for such a trigger in people who had
become narcoleptic, Mignot's group found elevated levels of antibodies to Streptococcus pyogenes, a bacterium that causes strep throat and has been implicated in other autoimmune diseases, such as rheumatic fever.
Any strong emotion — sadness, elation, laughter, fear — can cause an attack to come on: The
narcoleptic's muscles slacken and his or her face or body may
become weak and begin to sag.