The strength of modern diagnostic systems in psychiatry lies in nosology, that is, in the systematic collection of knowledge and in the description and differentiation of the complex phenomena which become manifest as psychiatric disorders. In consequence, the well-established diagnostic systems ICD-10 and DSM-IV have achieved a high degree of perfectionism, thus representing state-of-the-art instruments for the daily work of clinicians worldwide. Yet these diagnostic systems do not offer clinicians reliable guidelines for therapy and prognosis of a particular patient who suffers, for example, from functional psychosis. Only statistical information is available on psychotropic drug treatment, so that it is currently impossible to make any prediction of how a particular patient will respond to a particular antipsychotic or antidepressant therapy. The reason for this disappointing situation originates from the fact that psychiatric disorders are very heterogeneous and do not form distinct entities like most somatic illnesses, while the mechanisms of action of psychotropic drugs are likewise not well enough understood.
Moreover, little is known about the etiology of psychiatric disorders in general and, particularly, of functional psychoses. Even though strong evidence from adoption and twin studies underlines the significance of genetic contributions to the development of functional psychoses, the usefulness of psychiatric diagnoses in the context of phenotype definition is rather limited, as they delineate the familial aggregation of these disorders insufficiently and do not elucidate the modes of genetic transmission from one generation to the next.
Multidimensional quantitative approaches to disentangling the complex processes that underlie psychiatric disorders, their development, acute phase, and further course, apparently offer some major advantages over the qualitative taxonomy of diagnostic systems. Empirical data from our studies carried out over the past two decades clearly support this view, as the chosen multidimensional approach to psychopathology based on quantitative syndromes has turned out (1) to resolve the fine gradations of within-family psychopathologies, (2) to possess a strong biological component as revealed by significant correlations between the severity of illness and molecular-genetic quantities, (3) to model genetic predisposition across ethnicities well compared with epidemiologic data, (4) to relate to the time course of recovery under psychotropic drug treatment, and (5) to lead to a generalized model of genetic vulnerability to functional psychoses, where none of the vulnerability factors by itself is necessary or sufficient for the development of the disorder.
For details see Institute for Response Genetics.
If you have questions or comments concerning the research projects listed above send e-mail to one of the following addresses: