The need for security is the basic psychological need that man experiences. The spatial organisation of an artificial environment may favour the satisfying of this need, or on the contrary - arouse emotions of anxiety. A group of specific psychological hazards is distinguished which can be related to the spatial organization of an artificial environment and can become the source of anxiety states. These are hazards associated with: 1) loss of spatial orientation, 2) large scale and dimensions of buildings and complexes, 3) the complexity and differentiation of spatial systems, 4) the open and closed nature of spatial form, 5) the geometrical type and plastic nature of the forms employed, 6) the symbolical significance of these forms. An understanding of these hazards may contribute to reducing anxiety states and the elimination of unnecessary psychological tension.