Drug abuse future developments

Even when a disease has been effectively treated in a conntry, retention of the disease in small isolated pockets can act as a source for future infection. This can readily occnr when movement of even a small nnmber of infected people into a population in which the immnne system is impaired can lead to the spread of this new disease to areas that were previously free of it. Chronic illness due to malnutrition can weaken the immune system which then facilitates the spread of an infection. This is a particular problem if malnutrition is accompanied by a chronic illness. Althongh malnutrition and accompanying diseases are associated with developing countries, the phenomenon also occurs in developed countries, for example, in the very poor, the homeless, drug abusers and the elderly. It is now considered to be a major factor in the increased incidence of tuberculosis in these gronps. 

Animal research has revealed that antagonists, such as ketamine, phencyclidine, and dizocilpine [MK-801], at the NMDA receptor channel complex are clearly anxiolytic in animal models of anxiety. Because of the risk of abuse with phencyclidine-related drugs, which are thought to act at a site within the channel itself, antagonists at another site associated with the NMDA receptor channel complex—namely, those that act at the glycine-modulatory site on the NMDA receptor—are believed to have promise in the development of future anxiolytics [Hamon 1994]. 

The development of some of the secondary models such as conditioned place preference and electrical brain stimulation which do not require intravenous drug injections will continue to occur (for complete descriptions of the conditioned place preference paradigm and validation data, see Bardo and Bevins (2000) or Cunningham et al. (2006, 2011) for a complete description of the electrical brain stimulation model, also see O Neill and Todtenkopf (2010) or McBride et al. (1999)). A better understanding of the predictivity of these models and correlation with the traditional self-administration model will be required for these models to assume a mainstream position in abuse potential assessment. The self-administration model s predictive correlation to abuse potential in humans has been well characterized but new models will have to be characterized and published to have equal impact in future abuse potential testing. 

Other considerations that will shape the future include a better understanding of potential screening approaches for abuse potential, how to handle large molecules (see de Zafra 2014), and the development of a broader database for resolution of drug development strategies and the selection of comparator compotmds. 

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