Presents cost estimates for six preventive interventions previously identified through a literature review & analysis of peer-reviewed, published research in mental health or substance abuse services. A report by Dorfman in 2000 yielded a number of well-designed research studies. Twenty-one of those studies supported six preventive interventions that demonstrated patient benefits (i.e., better outcomes) or lower use & cost of medical care. The six are: prenatal & infancy home visits for high-risk mothers; smoking cessation targeted at pregnant women; targeted short-term mental health therapy; health promotion through self-care education; pre-surgical educational intervention with adults; & brief counseling to reduce alcohol use.