Numerical taxonomy applied to Leonhard's classification of endogenous psychoses

Among the existing classifications in the field of psychiatry, Leonhard's comprises 35 forms of endogenous psychoses, allowing a more precise differentiation. Computer-assisted mathematical methods of numerical taxonomy, frequently used in other fields of biological sciences, were used to check its coherence, definitely proving its taxonomic validity. Numerical values were assigned to signs and symptoms described by Leonhard, taking into account their frequency and diagnostical importance. The resulting data matrix was processed, obtaining the dissimilitude coefficients and the main components which validate Leonhard classification. This method can be applied to other psychiatric classifications validating them or displaying their weaknesses.