How Much Does A Private ADHD Diagnosis Cost? You may need to go the private option if you are an adult who suffers from ADHD. This is a good option since many private psychiatrists have experience in diagnosing adults suffering from ADHD. They also look for co-morbidities such as depression http://www.stes.tyc.edu.tw/xoops/modules/profile/userinfo.php?uid=1914065