Sleeping much more than usual
Eating less or more than usual
Losing interest in play, toys, or activities they normally enjoy
Hiding or avoiding people more often
Becoming less affectionate or unusually clingy
Grooming less, leading to a dull or unkempt coat
Litter box changes, such as accidents outside the box
Vocalizing more or less than usual
Acting irritable, withdrawn, or unusually quiet
Changes in body weight
Reduced curiosity or engagement with surroundings
Not responding to attention the way they normally do
Signs lasting more than a few days
Behavior changes after a move, new pet, loss, or other major change