The potential relevance of the planning process to mental health is rwo-fold. First, it can have an indirect effect on mental health as a preceding cause of many of the aspects of the environment already described as potentially relevant to mental health in earlier chapters such as pollution, density, traffic, fear of crime, or the relations between neighbours (all of which have been shown to be affected by design features) . However, it was reasonable to discuss these aspects of the environment without dose reference to the planning process that may have helped create them. Generally, the planning process is not a unique cause of these environmental problems and would not have explained further variance in levels of distress.' In other words, the causal relevance of the planning process could be considered as independent from the final effects. Second, the planning process may have a direct effect on mental health. Sometimes the planning process cannot be separated from its outcome as the process itself is implicated in how the event or environment is experienced. Perhaps the dearest instance of this is the effect of relocation and slum dearance, which is explored below. This discussion is followed by a more general consideration of the importance of resident participation in the planning process. The possible conflict berween the aesthetics of designers and residents is discussed. Finally, a study is presented ofthe impact of aseries of planning decisions on the 2000 residents of a New Town housing estate unexpectedly threatened with demolition.