I was doing some research (helping a friend) who complains of being constantly dizzy and disoriented. He had a panic attack in his car a few months ago and now everytime he gets into his car he comes close to suffering another one. However, the dizziness and disorientation (he also has problems sleeping) are constant, car or not. His parents think it's anxiety but I'm not quite sure.
What other diseases or disorders can cause those symptoms?