Many names, including muscular rheumatism, fibrositis, psychogenic rheumatism, and neurasthenia were applied historically to symptoms resembling those of fibromyalgia.
In the 1920s and 1930s, new theories of the cause arose, with physicians proposing a combination of nervous system and psychological disorders such as nerve weakness (neurasthenia) and female hysteria.
Many soldiers returned with severe trauma, suffering from shell shock (also called neurasthenia, a condition related to posttraumatic stress disorder).
