Nearly a third of all people with dementia feel "trapped in their home" and have given up on going outside, according to an Alzheimer's Society report.
In an article for ITV News, Philip, who is 69 and suffers from Alzheimer's, has written about his frustrations and fears over his illness.
My name is Philip. I am 69, live on my own in south-west London, and I have dementia.
Lots of things have happened to me over a period of time, since the onset of the illness. It's a gradual thing. Things start happening and you don't realise there is problem.
But as time goes by, you start to do things, things happen to you, and when they happen, a misunderstanding can easily turn into a confrontation, and then I can get anxious and stressed out. Then everything gets a bit foggy. It's like a black out, and you don't really know what you are doing.
One of the most stressful things that's happened to me was an encounter with a bus driver. I wanted to get off a bus at my stop. I have arthritis, and had my shopping trolley with me. So I asked the driver to lower the ramp.
He said that it didn't work, so I asked him if it had been reported, because I needed the ramp to get off. He said 'No. Get off my bus'. Then he swore at me and just looked away. I told him I was going to report him and he closed the door and drove on.
I started to get into a panic, and had a dizzy spell. He was threatening me and said he would throw me off. In the end a policeman had to help me off the bus. I think I got lost after that, because my brain was completely out of it. After that I didn't want to go on buses and I ended up feeling completely isolated.
I have regular contact with the Alzheimer's Society and I had to have a talking session to help me to try to get over it. It didn't work. In the end I had to have a nurse help me get over it by helping me on the buses, and I had to pay for home help to do my shopping.
One time I went on the Tube and I asked a chap if a train was going to a particular place. He said it was the next one. But I got on the train, not a tube, and I ended up somewhere in the countryside and I had to get off the train.
I got into a bit of a panic and I wondered what I had done wrong. I can't quite explain it, but it's like a foggy, dizzy spell. I don't think it's because people don't understand - I find a lot of people don't have time for you, and they don't put themselves out.
If you ask a question, people often don't want to help. If people don't help, I get confused, then I forget the words to express myself, and I get anxious because people start thinking something’s wrong with me.
I worry people will try to take advantage, and sometimes they do.