RESUMO
INTRODUCTION: The prevalence of Attention Deficit Hyperactivity Disorder (ADHD) in children varies due to the methodology used. In Mexico, the health sector recognizes difficulties in measuring and treating it, so the WHO recommends carrying out screening in populations with a probability of presenting it. The objective was to measure the prevalence of ADHD for screening purposes in second-grade students, their comorbidity, and to describe the experience using version 3 of the Conners scale. METHOD: Descriptive observational study, with the purpose of screening, applying the short versions to parents and teachers of 3,985 schoolchildren in a sample of 55 public schools obtained at random from two delegations in Mexico City, the cases were referred to psychology and psychiatry to corroborate diagnosis and treatment. Results We detected 458 (16%) cases, both informants, the prevalent subtype was hyperactive in both sexes, predominantly male, learning problems and executive functions more frequent in girls with hyperactive and combined subtype, only completed the psychological evaluation 150 schoolchildren and 127 attended with the paidopsiquiatra, who confirmed 72% of the cases. CONCLUSIONS: The prevalence for screening purposes, subtype of ADHD and affected gender is similar to that reported in the literature, the comorbidity identified by both informants is an advantage offered by the Conners scale 3, the limiting factor to corroborate the diagnosis was the resistance of the parents to go with the specialists. It is necessary to guide and inform parents more about the disorder to achieve better participation.