I'd like to think so. Or it could be a case of a condition lying undetected for so long that in the end it causes a disability, either mentally or intellectually. A case in point is the late famed actor Robin Williams who, after his death, was discovered had an underlying condition that was undetected.
In 2014, Williams was given a Parkinsons disease diagnosis but after his death, a brain autopsy revealed he had Lewy Body Dementia.
Lewy Body Dementia starts out like Parkinsons Disease so its easy to confuse them while make it hard to diagnose and treat effectively.