I answered this question.
This is such a syndrome that includes everything in general, which is not clear to the doctor. Especially if a young girl sits at the reception and presents non-specific complaints in the form of weakness, dizziness, headache. In general, there is no such diagnosis. It seems to me that this is a purely Russian diagnosis, and the literacy level of our doctors is often very low. Of course, such a syndrome can be found in a patient without even trying. But something has to come later, right? VSD can occur in various diseases and this disease must be looked for, than our doctors after "VSD" do nothing of the kind, but prescribe some "miraculous" vitamin complexes. There are similar conditions in ICD, namely somatoform dysfunction of the autonomic nervous system (F45.3) and disorders of the autonomic nervous system (G90.9). But these things have very specific symptoms. That is, as if a hint that some kind of neurological or psychiatric diagnosis should be formed, as well as somatic diseases that can cause certain symptoms should be excluded.