It could be possible, but I don't know too much into it. Does she have any other "quirks" that make you believe that she could be suffering from mental illness? If not, it could be she's just darn slow. Dogs, like people, learn at different rates. And like people, different dogs learn differently. If what you're doing isn't working and it's been that long without the slightest hint of progress, I would say try a different approach. Do you mind describing in what way she's not getting potty training and commands? And how are you trying to teach her potty and commands?