Palmomental reflex, glabellar reflex and oral responses were studied in the course of a treatment with Haloperidol in 14 psychotic patients with a chronic organic brain damage. An increase of the three responses was found; maximum intensity and frequency of the primitive reflexes were reached during the first 5 days of treatment. There was no correlation found between the intensity of primitive reflexes and changes of psychopathological symptoms, of extrapyramidal scores and of homovanillic acid (=HVA) and 5-hydroxyindoleacetic acid (5=5-HIAA) concentration in cerebrospinal fluid (=CSF). The presence of primitive responses is interpreted as a "decompensation phenomenon" induced by neuroleptics, probably in relation to an effect on the central nervous system (=CNS) dopamine receptors. It is suggested that the appearance of several definite, primitive reflexes during neuroleptic therapy may have some diagnostic and prognostic significance.