Certain functional disorders, inadequately classified as neurosis, arise from a pure reflex mechanism, not a psychogenic one; only later on the evolution psychic elements apear and complicate the clinical picture. Illustrating this concept the author presents and comments cases of vasovagal disorders following cranial trauma, colitis, incoercible vomiting, hiperfagia and anorexia, in which the initial vegetative reflexes criated conditions for the installation of psychic disturbances. It this pointed out how these reflex disorders are established and complicated with neurotic symptoms, depending on the patient's personality and on the existential value of the vegetative reflex disturbance. The relationship between constitution and the aptness to acquire reflex disfunctions is outlined. Patients with mental defectives and/or with endocrine disorders are prone to present such disturbances. The author thinks that many cases of nocturnal enuresis, dysmenor-rhoea, nervous urinary disorders, impotence and frigidity seem to be originally simple "reflex physiogenic disturbances".