In 1880, Dr. George M. Beard published a book called A Practical Treatise on Nervous Exhaustion (Neurasthenia): Its Symptoms, Nature, Sequences, Treatment, with a follow up in 1881 called American Nervousness: Its Causes and Consequences. In these two works he detailed a new disease called neurasthenia, in which nervousness is caused by the lack of “nerve-force” and over-exposure to “modern civilization.” Beard thought excessive intellectual effort caused nervousness that manifested itself in various physical forms, including dyspepsia and sick-headache, two of the illnesses often targeted by patent medicines. In a chart at the front of the book, reproduced on the left, various physical maladies are presented as the “Evolution of Nervousness.” The first part of the chart lists “Nervous Diathesis” or the idea that one illness or source of stress may lead to the next. The second shows the various kinds of nervous exhaustion that nervousness may lead to, with three final outcomes: inebriety (addiction, not to be confused with drunkenness), epilepsy, or insanity.
Today neurasthenia is defined in the International Classification of Diseases (ICD-10) as type of neurotic disorder that often demonstrates a diversity of symptoms depending on the culture it is diagnosed in. ICD-10 states that generally there are two types of neurasthenia – one that emphasizes mental fatigability and one that emphasizes physical weakness after minimal amounts of effort or work. The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) no longer uses neurasthenia as a diagnosis, but as a symptom; it is often described as fatigue and weakness by various cultures around the world, but is generally more of a catch-all term for unexplained physical complaints.