An American neuroscientist has developed a rare condition that leaves him paralysed when he feels the emotion of love. Matt Frerking, 39, from Portland, Oregon, is left immobile if he even has a romantic thought or sees others showing displays of affection.

The affliction has been diagnosed as a combination of the chronic sleeping disorder narcolepsy with cataplexy, a sudden weakening of the muscles which renders the person temporarily immobile but still aware of their surroundings and able to hear.

For Mr Frerking the feeling that sparks an attack is love and being around his family can send him into a state of physical paralysis.

I have to limit those things very carefully.” During an interview with ABC News, he described having to avoid “warm and fuzzy” feelings before passing out after looking at photos in his wedding album. Attacks are also triggered by trailers for romantic films and Mr Frerking said he tries to stave them off by thinking about scientific research. Carol Ash, a sleep specialist at the Sleep for Life Center in New Jersey, said: “In someone like Matt strong emotions are flipping a switch.”