The authors evaluated neuroleptic-induced extra-pyramidal symptoms (EPS) in 61 children and adolescents over four weeks of treatment. In patients treated with low potency neuroleptics, EPS was twice as common with higher doses > 300 mg, (60%) than with lower doses < 299, (26%) mg chlorpormazine equivalents. In patients who were neuroleptic-free before initiation of drug treatment, EPS were more than three times as common in higher doses (73%) than in lower doses (18%). The authors discusses the implications of these findings and suggests the use of prophylactic antiparkinsonian agents in combination with higher doses of low potency neuroleptics.