I applied for PIP last October as I suffer with severe depression, curvature of the spine, high blood pressure and cholesterol plus arthritis in my hands, right wrist, spine, right hip and right ankle. I eventually had a medical assessment a few months and was awarded the enhanced rate of PIP and motability. What helped though was the lady who did my assessment is an ex nurse so she understood my health issues and how to word it.
It does seem to be the luck of the draw who does the assessment as I know a couple of people who have been refused PIP yet have health issues that affect their daily living so need extra help.