Marked individual fluctuations in blood levels of GABA and GDC revealed in 35 to 50% of adolescents exposed to ionizing radiation several years before indicate the presence of an imbalance in the GABA-ergic system. These children (with GABA-ergic system disturbances) represent a group at risk of developing remote effects of radiation exposure presenting as disturbed rhythms and terms of sexual maturation, of growth, thyroid and adrenal abnormalities, and they should be regularly checked up.