If you are not doing substantial gainful activity, we always look first at your physical or mental impairment(s) to determine whether you are disabled or blind. Your impairment must result from anatomical, physiological, or psychological abnormalities which can be shown by medically acceptable clinical and laboratory diagnostic techniques. A physical or mental impairment must be established by medical evidence consisting of signs, symptoms, and laboratory findings, not only by your statement of symptoms (see § 416.927). (See § 416.928 for further information about what we mean by symptoms, signs, and laboratory findings.)