You know that old trope "Crazy Cat Lady?"

[Byrd]

You know, the reverse could be true.  It could be that people with very troubling psychological problems find cats helpful; a friendly little presence that is less trouble to take care of than other pets.  Food and water and a place to sleep... unlike dogs, you can fill their bowl with kibble and they'll graze as needed.  Many people don't bother with a litterbox, but let the cat outdoors (or install a cat flap.)

Don't need to change cage liners, don't need to take them on walks.  

Low maintenance pet, comforting purr when you're stressed.