Your Social Security disability claim is largely reliant on medical evidence that must support all of the elements of your claim in order to be approved for disability benefits. You must use medical evidence to show that you have a “medically determinable” physical or mental impairment which has lasted or is expected to last for at least 12 months, or is expected to result in death, and that prevents you from engaging in substantial gainful activity. Your medical evidence should show that you meet the time and severity requirements.