Yes, my friend was forced to put her cat sleep for sake of her children. Her cat was loving for long years until suddenly... Her cat was hissed and jump on her like lion's attack to human being and then bite and scratch her face. It's not normal...
The vet confirmed mentally sick due her age... but it's extremely rare, the Vet said...
Yes, she noticed something on her cat's behavior... become into unfriendly cat... and bite and scratch when she or her children want to pat or cuddle her.... something like that - "LEAVE ME ALONE"... My friend never thought about attack when she thought it's something do with cat age... when she questioned me via MSN chat... Her cat was 12 years old that's time. Few days later after that, her cat suddenly jumped to attack her like lion did to human being or animal... bite her neck and then scratch her face when she was about feed the food for her...