How Much Does A Private ADHD Diagnosis Cost? If you are an adult with ADHD You may have to go through a private process to be diagnosed. This is a great option since many private psychiatrists have experience in diagnosing adults with ADHD. They will also screen them for co-morbidities http://www.stes.tyc.edu.tw/xoops/modules/profile/userinfo.php?uid=1557478