ABSTRACT
Since the turn of the century, clinical studies of anxiety have appeared in the psychiatric literature with increasing regularity. Prior to 1950, however, there were relatively few experimental investigations of human anxiety. The complexity of anxiety phenomena, the lack of appropriate instruments for assessing anxiety, and ethical problems associated with inducing anxiety in the laboratory all contributed to this paucity of research. With the development of self-report procedures for the measurement of anxiety in the early 1950s, experimental research on human anxiety has rapidly accelerated, and more than 5000 articles or books on anxiety have been published during the past two decades (Spielberger, 1972a).
