In the 17th century, French philosopher Rene Descartes, without addressing the concept of stress reaction in his writings, nonetheless had a profound impact on psychology, the new scientific pursuit of many of his contemporaries who were beginning to understand the impact of psychological stress on human functioning.
Descartes’ thoughts also touched on the relationship between mind and body. In his view, mind and body were clearly separated, although he recognized that the body could somehow influence the mind, or vice versa. In particular, as Descartes put it,
…as regards the soul and the body together, we have only the notion of their union, on which depends our notion of the soul’s power to move the body, and the body’s power to act on the soul and cause its sensations and passions (Descartes, R., Oeuvres de Descartes, 11 vols., eds. Charles Adam and Paul Tannery, Paris: Vrin, 1974-1989.)
An important contributor to the understanding of psychological stress was the noted American physician George Beard (1839–1883), a specialist in diseases of the nervous system. Beard hypothesized that the newly imposed demands of the Industrial Revolution on 19th century life may cause an overload of the nervous system.
He variously labeled this overload as neurasthenia, a weakness of the nervous system, or nervous exhaustion. This condition, very much equivalent to our modern understanding of chronic stress, was characterized by Beard has exhibiting symptoms of severe anxiety, unexplained fatigue, and irrational fears—a state of affairs that caused an inability of the individual’s nervous system to meet the demands of daily life.