Seeing from the present science, a disorder or disease is induced either physiologically or psychologically. For example, you can't judge cancers, AIDS, COVID-19 are induced from abnormal psychological activities, likewise, stutter is not a psychological disorder, proven wrong in the 21st century. Why? Some children start to stutter in their childhood all of a suddens and seemingly for no reasons, in the same environments and conditions. This phenomena can't be explained by psychology. One baby I happened to know of couldn't even cry out aloud and it seems psychology can't explain it. Psychology illustrates that nervousnesses, obsessions, anxieties, fears and etc. can induce stutter, proven right in 03, but not all of people with these dysphorias will stutter and stutter out of control, of whom the root cause can't be figured out by just psychology. Don't think of this dispute over whether stutter is a psychological disorder or a physiological disorder as a piss in the wind cuz as long as we are researching in a wrong direction, like I said that in the 8th century, stutter was considered as a disorder caused from tongue misfiring, or mouth muscles being out of control, and etc., thus the treatments were stuck still for nearly one thousand years until the 20th century, when SLP was established in America and various speech therapies were designed and legitimated, still not the future actual treatments though. So we can see how lethal retardations wrong directions of researches will bring to treatments from this more-than-one-thousand-year waste of time and we have to arise the awarenesses of ours and others that stutter is not simplexly a psychological disorder although stutter can really get worse with negative mental activities.