RESUMEN
The present study analyzed the effects of age and gender on performance on the Conners' Continuous Performance Test (CCPT II) in a sample of Brazilian adolescents aged 12-17 years. The sample consisted of 480 participants (210 boys) with a mean age of 14.34 years (SD ± 1.61 years) who were representative of the socioeconomic class distribution of the city of São Paulo, Brazil. The participants were prescreened for attention-deficit/hyperactivity disorder. The present results found effects of age and gender that were similar to other Brazilian age groups. Compared with males, female participants presented a lower rate of responding to non-target stimuli (i.e., commission errors), a greater ability to discriminate signals (d'), and fewer impulsive responses (i.e., less perseveration) but longer reaction times (Hit RT and Hit RT Std Error). A significant effect of age was found on RTs (Hit RT, Hit RT Sdt Error, Variability, Hit RT Block Change), commission errors, and perseveration. As age increased, the differences diminished. The present results may be useful for research and clinical studies with Brazilian adolescents.