[This elusive unknown quantity: reflections on the prescription of psychotropic drugs in early childhood].

The scope of this article is to study aspects related to prescription habits and the use of psychoactive drugs in early childhood. It takes as a starting point the bibliographical survey carried out on the BVS and Scielo databases on epidemiological and clinical research in Brazil regarding the use of psychotropic drugs in children under six years of age. Based on international literature, it highlights the increase in the number of children diagnosed with mental and behavioral disorders, as well as the respective prescription of psychotropic drugs. It discusses the predominantly off-label character of psychoactive drugs for children under six years of age, the heterogeneous use of prescriptions and polypharmacology, pointing to an ethical paradox regarding clinical research in this age group. It concludes that the use of psychotropic drugs in early childhood is as yet not well known in Brazil, and epidemiological studies are urgently needed in this area.