Not just a state of mind. Disability in my opinion is also physical. Not being physically able to see, able to walk due to a physical problem (or disease) not allowing it. There are many more. But being disabled can be both physical and mental.
An old movie with Lee Majors, Just a Little Inconvenience. Lee helps a friend to relearn how to downhill ski afer loosing his left arm and leg in Vietnam.
The title says it all.