It is much easier to make an exact calculation of the direct treatment costs of intervention than the often hidden indirect costs of nonintervention. This chapter reviews cost-effectiveness studies that explicitly compare benefits in relation to costs and risks in other areas of medicine. It examines a number of research initiatives currently underway to study the indirect costs of psychiatric disorders and the extent to which these costs can be reversed with intervention. The chapter recommends that mechanisms to assure the quality of interventions have to be developed as part of cost-effectiveness studies if we hope to persuade policy makers to increase the allocation of health care resources to psychiatric disorders. It argues that while process assessments have to play a prominent role in any plan for the quality assurance of psychiatric interventions, special features of psychiatric disorders make them especially appropriate for outcomes assessment.