translates into generating evidence on affordable and cost-effective mental health care and prevention strategies. Economic evaluation provides a methodology that allows policy makers, managers and clinicians to make choices between differing treatments, settings and illnesses in order to facilitate the judicious use of scarce resources. The current lack of mental health economic evaluative studies in low-income countries is a significant stumbling block to the investment of resources in mental health by governments and international agencies.
Key to the understanding of an economic approach towards mental disorder is the notion of resource scarcity, since this necessarily prompts the requirement to make choices between different courses of possible action or investment. Making a choice implies in turn the sacrifice or foregoing of the alternative action or investment. The economic approach therefore attempts to value the worth of a particular resource, decision or strategy with reference to its “opportunity cost,” namely the value attached to the next best alternative. To give an example, the opportunity cost of an acute psychiatric bed is derived with reference to the alternative use with which those resources could be put to, such as within another medical speciality, outside medicine completely, or investment into an interest-bearing savings account. A further important principle of economic analysis is that it takes a broad, societal perspective, such that account is taken of costs falling to all relevant parties; for example, allowance should be made for inputs of unpaid volunteers/family carers as well as formal care inputs.
For an appropriate economic evaluation of a mental health care intervention, program or strategy, a number of study design features need to be considered. Since economic evaluations often take place alongside clinical evaluations or trials, the design of the study will typically need to be agreed to in conjunction with other evaluators. The most desirable design requirements for the economic evaluation of a mental health care intervention revolve around the presence of a control group (against which to draw comparisons with the intervention group), and the prospective follow-up of these two groups over time (one year would be sufficient for most studies). This “experimental ” study design is the “gold standard” of clinical and economic evaluation, since it is able to demonstrate most clearly that changes in selected measures are attributable to the intervention, as opposed to other possible explanatory factors (“confounding” variables). Where it is not possible or practicable to carry out an experimental study, an observational study design can be used; this design may have better external validity—preserving the context in which care is provided—but shifts the focus of the analysis towards identifying associations between the intervention and changes