<qa>  What is the primary aims of children?Important secondary aims include the assessment of non-metabolic adverse events, and the assessment of each antipsychotic treatment condition in children with and without concomitant stimulant therapy. Reduced adverse metabolic effects are hypothesized during concomitant stimulant therapy. Children aged 7-18 will be studied, exploring age-related differences in vulnerability to treatment-induced adverse metabolic changes. Finally, treatment effects on regulatory hormones, including cortisol, glucagon, leptin, ghrelin and adiponectin will be explored. This will allow the assessment of possible confounds to the interpretation of the primary hypotheses. It will also permit the generation of additional hypotheses concerning mechanisms contributing to drug-induced changes in weight and fat mass. Relevant data on the primary and secondary aims are critically needed to assess the risks as well as benefits of clinical therapy in children, to identify needs for additional basic research, as well as to guide administrative and regulatory decision-making. 