This chapter is devoted to the psychological and psychiatric aspects of population analysis. Traditionally, demographers have utilized the basic triad of fertility, mortality, and age composition in the analysis of changes in a given population. In this chapter, an expanded, more psychologically oriented approach will distinguish between two types of population variables: structural and dynamic. The structural variables of size, distribution, and composition are inherent aspects of any population. The dynamic variables of fertility, mortality, and geographic mobility result from, or are affected by, individual decisions and behavior through which they have an aggregate effect on the population. (112 pp.)