The Use of an Object Sorting Test in Elucidating the Hereditary Factor in Schizophrenia.

Much evidence is now available as to the importance of the hereditary factor in the causation of schizophrenic psychoses. However, the mode of inheritance still remains doubtful, Luxemburger and Kallmann favouring a recessive, and Lenz a dominant type. Kallmann has consistently advanced the theory that a specific recessive gene transmits the disorder, but that its effects can be successfully resisted by a "non-specific and certainly multifactorial type of secondary genetic mechanism" (Kallmann, 1952). He further considers that "the factor for schizophrenia, even though recessive, may sometimes be expressed in a merely heterozygous condition, but only to the extent of schizoid personality changes. . . Schizoid types may be either heterozygote with little resistance to an intermediate expressivity of their single gene, or strongly resistant homozygotes" (Kallmann, 1946). If this theory is correct, both the parents of schizophrenics must be either heterozygous or homozygous with respect to this gene, and so may show these schizoid personality changes. It was therefore considered that it would be of interest to investigate the possibility that the parents of schizophrenics show schizoid features more commonly than a control population.