milieu therapy. Despite this success token economies declined from the 1980s on. Controversy The application of token economies, especially with adults, became a matter of criticism. In addition some impediments and the evolution of mental health care caused troubles. Token economies have proven their effectiveness and utility for chronic psychiatric patients, despite requiring months or even years to achieve optimal results. This causes problems when insurance and government policies increasingly require the shortest possible hospital stays. Because emphasis has shifted to community-based treatment, outpatient and home-based care is often the preferred choice over institutionalization. This decentralization of patient care methods makes it difficult to further study and develop token economies in a scientific, research-oriented method. Token economies can present issues with concern to patient rights. The right to have their personal properties, basic comfort and freedom of choice of treatment constrains the possibilities for token economies. In addition, ethical and personal concerns of staff members arose, such as the ethics of using certain reinforcers, the ethics of operant conditioning itself, a lack of sincerity, and an emphasis on material goods. Application of a token economy to adults sometimes triggers client resistance. Problems with maintaining what's been learned and the generalization toward new situations have also been signaled. When the token programs stops the acquired behavior might disappear again. Rewarding behavior could increase the extrinsic motivation and at the same time decrease the intrinsic motivation for activities. Applications and findings In the last 50 years much research has been conducted on token economy. Despite controversy and a lack of implementation token programs still exist in several settings. Adults In adult settings token economies are mostly applied in mental health care. When offered a choice, the vast majority of clients in past studies voluntarily chose to stay in the program. Research shows the effects of token economies can more or less be divided into three categories: No effect: 5 to 20% of the clients do not (or minimally) respond to the token economy; Only effect while the token economy is active and no effect once stopped: in this case the token economy is functioning as a prosthesis (like a wheelchair); it does not permanently help the patient once terminated but is necessary to maintain normal functioning; Well established long-term effects (including community reintegration). Schizophrenia The first token economies were designed for chronic, treatment-resistant psychotic inpatients. Even now token economies are applied to