Lynda
There are two questions related to PIP Mobility, Going Out and Moving Around
The Moving Around question, that you refer to in your post, is primarily concerned with your ability to physically walk, I would not expect you to score points for mental health issues that prevent you from walking.
The Going Out question is primarily concerned with mental health or cognitive issues that would limit your ability to plan a route or to follow one.
Have a look at page 53 of the current PIP guide for more information.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems