David Hartley's views on Madness: With an introduction by GE Berrios.

The psychiatric aspects of David Hartley's writings have received less attention than the rest of his work. This Classic Text deals with Section VI of his Observations on Man …, namely, the 'Imperfections of the rational Faculty'. Hartley defines madness as an imperfection of reason that can be temporary or enduring. He makes use of his model of mental functioning to differentiate between eight clinical categories of madness, each representing a different pattern of vibrations of the nerves. Hartley developed this model based on Newton's theory of vibrations and, to explain the complexity of mental acts and entities, he combined it with his own version of the mechanism of Association of Ideas borrowed from John Locke. Much work needs to be done to identify the provenance of Hartley's nosology and nosography.