Natural history group 5806830 90113283 2006-11-25T23:44:51Z Alex Peppe 374243 Clean up of summary The term '''natural history group''' refers to subjects in a [[drug trial]] that receive no treatment of any kind and whose illness is, as a consequence, left to run its "natural" course. The term stems from the [[natural history]] of an [[illness]], which is the course and outcome of that illness in the absence of treatment. ==First usage== In 1863, [[Austin Flint murmur|Austin Flint]] (1812–1886) in his report of the first-ever trial that directly compared the efficacy of a placebo treatment with that of an active treatment, spoke of "the natural history of [an untreated] disease".<ref>Flint (1863), p.18.</ref> ==Third arm== The natural history group is often referred to as the ''third arm'' of a controlled drug trial, from the simple notion that a triad has three arms (or a [[triskelion]] has three legs). The observed outcomes within this group are then compared with the outcomes manifested by a group that has been given the active drug, and with that manifested by a second group who have been given a dummy, [[placebo]] drug (thus, the natural history group is the trial's "third arm"). ==Notes== <references/> ==References== * Flint, A., "A Contribution Toward the Natural History of Articular Rheumatism, Consisting of a Report of Thirteen Cases Treated Solely with Palliative Measures", ''American Journal of Medical Science'', Vol.46, (July 1863), pp.17-36. {{medicine-stub}}