Cinchona bark and quinine as psychiatric treatments in Portugal, 1700-1900.

Cinchona bark and its main medicinal derivative - quinine - are known antimalarials. Until the 20th century, medicines with Cinchona bark or quinine were the only effective treatment for malaria used on a large-scale. However, Cinchona bark and quinine were also used in other diseases. Regarding psychiatric uses, in Britain, Cinchona bark was recommended in mania (17 th century) and nervous diseases (18 th century). Nevertheless, the full scope of Cinchona bark and quinine's proposed activity in psychiatric disorders has not been assessed. We aimed to investigate references to Cinchona bark and quinine's use and recommendation in psychiatric diseases and symptoms in Portugal, published in the 18th and 19th centuries. For this purpose, we reviewed Portuguese medical and pharmaceutical literature from this period. Our sources included books (namely pharmacopoeias) and periodical publications. We found 27 Cinchona bark or quinine medicines recommended in the treatment of psychiatric diseases and symptoms in Portugal. Those diseases included hysteria, hypochondria, and nervous diseases. Cinchona bark and quinine medicines were also advised in psychiatric symptoms such as anxiety-induced palpitations, melancholia, or hypochondriac or hysterical symptoms. For most of these medicines - 17 out of 27 - the authors mention their efficacy in clinical practice. Consequently, our research suggests that, in 18th and 19th -century Portugal, Cinchona bark and quinine medicines were a therapeutic option in various psychiatric conditions. Therefore, it is possible that Cinchona bark and quinine had additional therapeutic indications that remain unknown.