Thank you for this. I'd say "anxious" was a good description for him right now. He is very unhappy being outside a room he knows someone is inside, and I sent the original question to you after having him pawing me (with very sharp claws) for 2 hours between 2am and 4am (I'm in the UK). He seems happy enough sitting with/on someone, but obsessively so. He had his regular check up with his annual jabs, but they don't normally include blood tests here with that, so I think hyperthyroidism may be a good call, although at the moment he has no weight loss problems, but he will eat four five times a day if we let him. I will also investigate the Feliway too - we have black marks over all sorts of bits of furniture right now as he is also marking more than usual. I'll be making a vet appointment for him today. Thanks.