Certain tests can only be administered by a clinical psychologist. From what I know they are the only ones who do neuropsychological testing (for ADHD or Autism for example). they also do intense psychological testing for other psychiatric disorders. As far as I know, psychiatrists don't do this testing. To go to SSI for a claim, you need a detailed psych evaluation and this would be from a psychologist. A social worker or licensed counselor can give you a diagnosis, but they do not do diagnostic testing. That requires special in depth training and is only done by someone with a doctoral degree. And takes hours. My daughter has Aspergers and had a full neuropsych done (about 4 hours though they said it would be 8). She needs this documentation for any school or government supported services. It is the same with ADHD. It doesn't seem to make sense that you can't get it all from one provider, especially a medical doctor, but that is the way the system is set up. They make it very difficult on purpose I think so less people apply for services. I hope this is helpful. Do you have insurance? These tests are very expensive but most insurance covers them to some extent.