A Psychiatric Perspective on Human Development
The miracle of human development has always fascinated phy-sicians. Psychiatrists and pediatricians have formally studied developmental processes and used the knowledge gained from these investigations to create more effective strategies for care of patients. With the evolution of the specialty of geriatrics, interest in the developmental changes that occur after having achieved full maturation has further expanded the scope of investigations. With better understanding of the changes that predictably occur in the last half of life, it has become possible to link more ef-fectively early precursors of illnesses to the later expression of developmental delays and deviations.
There are two classical approaches to the study of human development: the stage model and the longitudinal lines of develop-ment model. Each has distinct advantages and disadvantages. The more traditional approach is to examine each stage of development. Consequently, the unfolding of the many new capabilities of the in-fant is reviewed chronologically so the child as a whole can be bet-ter understood. Thinking about development as a series of stages is a particularly useful approach for clinicians. In this regard, it is traditional to address the development of 1) infants, 2) preschool children, 3) school-age children, 4) adolescents, and 5) adults. Sometimes it is helpful to distinguish phases within these groups. For example, it is common to describe adolescence as being com-prised of early, middle, and late phases as illustrated in Table 7.1.
An alternative strategy used to teach development is to choose a particular aspect of human development and track it
from birth until death. This is a helpful strategy for understanding the process of development and is useful for researchers who are searching for the antecedents of characteristics that occur during later developmental periods. However, accurately charting these lines of development has proved to be difficult. Clearly, it is not feasible for a single investigator to study the extensive changes that occur over the lifespan. In the rare longitudinal studies that span at least 10 years, it is usually necessary for a series of prin-cipal investigators to work sequentially in order to achieve con-tinuity. Consequently, most investigators become specialists in narrow age ranges of the developmental process and must work collaboratively with colleagues to link together the transitions from infancy to childhood or adolescence to the adult years.