As someone formerly diagnosed with ADHD I tend to agree with you, but I thought there were studies which found specific genes and brain structures common to many people diagnosed with ADHD, I need to look in to this. On symptoms alone the overlap between trauma-noise and ADHD means someone with C-PTSD may share the symptoms of ADHD and vice versa but psychologists need only be aware of the conditions which are often confused and find criteria to rule one or the other out. There's no doubt that many of disorders/conditions in the DSM need more work to make them as helpful as they can possibly be, and for the world to recognize that they are clusters of symptoms not true things with firm borders (unless they turn out to be through neuro-science). Once certain issues become recurrent/troublesome enough to seek a diagnosis I only hope the DSM aligns people to something which is helpful, whether it be pharmicological or developing coping strategies. Some may find it invalidating for their DSM diagnosis to be questioned but it's not an attack on the validity of their problems, only on what the labels are referring to.