Introduction

The world is rapidly aging. The concept of a few older persons aging successfully into old age was well established at the time of the ancient Greek philosophers, e.g. Socrates, 98 years; Sophocles, 91 years; and Plato, 81 years. In 1900 the average citizen of the United States lived less than 50 years, whereas at the end of the century life expectancy has reached the late seventies. By the year 2030, the percentage of older individuals in the population of most developed nations will be approaching 20%. However, it is not only in the developed nations that persons are living longer. By the year 2000 approximately two-thirds of older persons will live in developing nations, e.g. 300 million in China and 170 million in India.

It is against the backdrop of this age wave that there has been an increasing interest in understanding the scientific basis of the aging process, both physiological and pathological. In the area of mental disorders and aging there have been tremendous advances in our understanding of the pathophysiology of these disorders and an extraordinary development of new therapeutic agents.