For an adult to be considered disabled by Social Security, he must have a medical condition that prevents him from working and that is expected to last for at least one year or result in death. Social Security uses a five-step process to decide whether you are disabled. As part of that process, it will check to see if a claimant has a condition as described in the listing of impairments. If he does, they consider his medical condition to be disabling. Even if his particular medical condition is not on the list, he may still be determined to be disabled.