First I thought that Billy had a double and I was fussing and feeding two cats but as Billy has been in the last few days, I've realised that he seems to have two personalities. Is it possible for cats to have mental health issues? He's either got schizophrenia or a very early onset of dementia, which is unlikely I'm sure. I'll explain below. Billy is one years old and is an outdoor cat but occasionally does like to stay in. He comes to me when called and sleeps indoors at night 99% of the time. Recently (like the last few weeks) I've noticed a big change in his behaviour. He is not normally very vocal or shy in any way. Sometimes he is his normal self, my baby Bill - very affectionate, purring, sits on my lap for hours, asks to go out and asks to come in a few hours later, eats three times a day, plays with ribbon and comes up to me to kiss my nose, likes being fussed, generally very happy and loves being carried round like a baby, sits near the dog and licks her. Then other times it's like a different cat in my house - very vocal, five minutes after being fed he's meowing for more until he gets so distressed that he seems to scream until I give in, meowing to go out then when the door shuts, meowing to be let back in (this goes on for about 15 minutes until I walk away in frustration as it ends in him almost screaming at me but he seems very confused like he has forgot he's asked to go out), He doesn't let me fuss him but follows me everywhere screeching for about half hour, making odd noises that I think means he's confused. He seems to forget sometimes that we have a dog and he'll raise his hair and hiss like he did the first time he saw a dog as a kitten. He'll walk in and out of the bathroom meowing, cowers when I do try to fuss him, doesn't purr during these episodes and just seems generally unhappy and confused. After this he'll fall asleep for four hours and then wake up 'normal' again. These episodes are slowly getting more frequent. I'm gonna get him to the vets when I take Princess the dog for her microchipping. What can I expect? Will they take a head scan or something?