Intoxicated with Madness: Exploring the Psychology of Intoxication in Uncovering the Experimental Roots of the Kraepelinian Dichotomy

Scholarship surrounding the Kraepelinian dichotomy of dementia praecox and manic-depressive insanity has overwhelmingly approached Kraepelin's nosology as the product of Kraepelin's clinical method, use of diagnostic cards, and pre-existing disease concepts, rather than his work in experimental psychology. Revisiting the significance of Kraepelin's 1881–1895 concept of intoxication as model psychosis, this article establishes that Kraepelin's earlier psychological experiments with intoxicants were a potential source of latent, synthesizing concepts, informing the organization of clinical data around two discrete forms of psychosis. Tracking Kraepelin's nosological system over the course of the first six editions of his textbook, it examines Kraepelin's classificatory descriptions relative to the content of his experimental studies on the psychometrics of intoxication, in particular the dualities Kraepelin finds in exogenous and endogenous psychoses. More specifically, it addresses the alignment of inhibitory and excitatory effects at the level of sensation and perception found within both Kraepelin's experiments and psychiatric nosology, proposing that manic-depression and dementia praecox conform with excitatory and inhibitory modes of exogenous psychosis.