A simple letter from your doctor can make you eligible for social security benefits. Non profit organizations like Neighborhood Legal Services, Inc. (NLS) provide information on the things to be included in a doctor's letter. They state that the doctor letter should mention ich disease your name and social security number. The letter should detail about the treatment you are undergoing from a doctor. Clubbed with the medical reports it acts a proof of your disability and make you eligible for the benefits. In case you are not able to find a doctor for this, these organizations can help you meet a doctor and can get you a doctor letter.