Pheno-phenotypes

Abstract

Mental disorders are mainly characterized via symptom assessment. Symptoms are state-like macroscopic anomalies of behaviour, experience, and expression that are deemed relevant for diagnostic purposes. An alternative approach is based on the concept of endophenotypes, which are physiological or behavioural measures occupying the terrain between symptoms and risk genotypes. We will critically discuss these two approaches, and later focus on the concept of pheno-phenotype as it is revealed by recent phenomenological research on schizophrenia. Several studies have been recently published on the schizophrenic pheno-phenotype mainly addressing self-disorders, as well as disorders of time and bodily experience. The mainstream approach to psychopathological phenotypes is focussed on easy-to-assess operationalizable symptoms. Thinness of phenotypes and simplification of clinical constructs are the consequences of this. Also, this approach has not been successful in investigating the biological causes of mental disorders. An integrative approach is based on the concept of 'endophenotype'. Endophenotypes were conceptualized as a supportive tool for the genetic dissection of psychiatric disorders. The underlying rationale states that disease-specific phenotypes should be the upstream phenotypic manifestation of a smaller genotype than the whole disease-related genotype. Psychopathological phenotypes can also be characterized in terms of pheno-phenotypes. This approach aims at delineating the manifold phenomena experienced by patients in all of their concrete and distinctive features, so that the features of a pathological condition emerge, while preserving their peculiar feel, meaning, and value for the patient. Systematic explorations of anomalies in the patients' experience, for example, of time, space, body, self, and otherness, may provide a useful integration to the symptom-based and endophenotype-based approaches. These abnormal phenomena can be used as pointers to the fundamental alterations of the structure of subjectivity characterizing each mental disorder.