There are often cost incentives to improving existing systems rather than building new ways of delivering treatment, and evidence suggest that mild-to-moderate disorders can be cost-effectively treated from primary care. However, in order for treatments to be effective and of high quality, the right capacity and knowledge, incentives, and information systems must be in place. In addition, some OECD countries have had some success in building additional tailored services to address unmet need for treatment of mild-to-moderate mental illnesses.