Two of the most common illnesses linked to nervousness were dyspepsia and exhaustion. While medical professionals and patent medicine manufacturers clashed over the treatment of these illnesses, they were in agreement that they were common problems. In one essay entitled Influence of Mental Cultivation in Producing Dyspepsia, Third Edition, published in an 1876 medical book, Dr. A. Brigham writes that, “Dyspepsia is generally considered a disease of the stomach primarily; but I apprehend that…it is a disease of the brain and nervous system, and is perpetuated by mental excitement.” Another 1875 text reports on the various symptoms of dyspepsia:
A sense of weight or uneasiness in the stomach after food, occasioned by the slowness of the digestive process...The circulation is depressed...the skin is soft, flabby, clammy, and moist, and the extremities are frequently cold, particularly after meals...Languor and inaptitude for exertion, and a sense of weariness in the limbs...an almost unconquerable drowsiness after food...an impairment of the intellectual faculties...chiefly affects the memory and attention.
Although medical professionals were much more direct in their definition than patent medicine manufacturers, dyspepsia was still a vague and unclear diagnosis. Better known today as indigestion, in the nineteenth century dyspepsia was often applied as a title to general ill-health and considered one symptom of nervous disease.