How Much Does A Private ADHD Diagnosis Cost? If you are an adult suffering from ADHD you may have to pursue a private path to be diagnosed. This is a good option because private psychiatrists are more experienced in diagnosing adults suffering from ADHD. They will also screen for co-morbidities http://www.stes.tyc.edu.tw/xoops/modules/profile/userinfo.php?uid=1372729