A variety of factors must be considered in developing assessment procedures to evaluate the cost of schizophrenia. One is the definitional problem: definitions of schizophrenia have varied over time and space, with a tendency in recent years to narrow the concept substantially. These changes in definition, which reflect the increasing scientific rigor in psychiatry, make the task of establishing base rates, assessing morbidity and mortality, and ultimately determining the cost of schizophrenia more difficult. Efforts to assess the cost of schizophrenia must also take into account the fact that its cost is not simply monetary, nor can it be conceptualized using only the cost of treatment. The overall cost of schizophrenia also includes social and psychological costs experienced by patients and family members. The concept of "the overall cost" is discussed--the sum of costs to the patient (including suffering, loss of productivity, and mortality), the cost to the family (including suffering and loss of productivity), and cost of treatment (including medications, rehabilitation services, day hospitals, inpatient facilities, etc.). At present, standardized techniques are available only for assessing some aspects of patient costs, while assessments of family and treatment costs are relatively underdeveloped. Over the long run, reduction of the overall cost of schizophrenia is most likely to come from investment in research. The most effective way to reduce the overall cost is to develop improved treatments, to identify the pathophysiology and etiology of schizophrenia, and ultimately to identify ways to prevent it from occurring.