Background : The aim of this investigation was to verify whether brain hypoxia represented a risk factor for the occurrence and severity of opioid abstinence syndrome. Methods : Three newborns who manifested seizure activity as a result of hypoxia, focal brain ischemia, and hypoxia and sepsis, respectively, were compared with 17 neonates who suffered from hypoxia without developing seizure activity. Results : The first three neonates suffered a severe withdrawal syndrome (a rating on the neonatal abstinence score >17), the others did not. Conclusions : It is hypothesized that brain hypoxia facilitated the occurrence and severity of the withdrawal syndrome because some key neurochemical processes (such as N-methyl-d-aspartate activation, protein kinase C activation and nitric oxide production) are common to both phenomena. [ABSTRACT FROM AUTHOR]