We have similar troubles with my sister. She has "learning difficulties" and has suddenly developed a fear of going through doors which are dark on the other side. It's a fear of the unknown. The astounding thing is, and it's something I cannot get my head around, she won't trust her mother who has taken care of her for 40 years when she says "It's perfectly OK on the other side. There are lights and everything". We can't even drag her in. But when a perfect stranger (like the ticket person at a museum or another visitor) tells her it's OK she capitulates. We're sure it's a mixture of fear of the unknown and attention seeking from anyone but the people she lives with.