brain spect imaging (bsi) with statistical parametric mapping (spm) offers a clear and accurate vision of perfusion changes. objective: to study brain perfusion abnormalities in adolescents' dependent of multiple drugs. method: sixteen male patients (15.1±2.1 years) were submitted to 99mtc-hmpao bsi with spm. results: cortical hypoperfusion occurred in 7/16 patients (44%). there was a significant inverse correlation between the number of hypoperfused regions and the patient's age (p= -0.6737; p=0.004) and with the age when the drug dependence began (p= -0.5616; p=0.023). there was also a tendency towards an inverse correlation between regions of hypoperfusion and the duration of the drug dependence. conclusion: bsi with spm can help detect hypoperfusion in adolescents dependent on multiple drugs. the younger the patients, the more regions of hypoperfusion are noted. probably, the neuronal plasticity has an important role in this phenomenon because the highest neural activity occurs in childhood.