Abstract
Recent attention to the early phases of schizophrenia has generated a renewed interest in the subtle, self-experienced cognitive, perceptual, and emotional changes that have been described since the earliest articulation of dementia praecox [1–3].
We agree with Dr Raballo [4] on the intrinsic developmental characteristics of subjective experiences in schizophrenia. According to the original concept, subjective experiences of psychosis occur in several developmental forms: the uncharacteristic basic symptoms, the characteristic and qualitatively peculiar basic symptoms, and the psychotic symptoms per se [2,3]. Following the first psychotic episode, basic symptoms evolve into the post-symptomatic basic stages where some forms of basic symptoms may persist on a level that interferes with functioning [2,3]. Therefore, the structure of the subjective experiences is sensitive to the patients’ characteristics and their illness stages, and is influenced by the instruments used for measurement. As noted in our article and as mentioned by Dr Raballo, the moderate magnitudes of the correlations between subjective experiences and objective psychopathology may be accounted for by this factor. In addition, it is likely that the observed features of patients (i.e. third-person data), and the patients’ subjective experiences (i.e. first-person data), gravitate into separate dimensions, without implying a real split between them or a homogeneity of subjective experience [5].
In assessing basic symptoms or subtle changes in the structure of subjective experiences, it is preferable to use the Bonn Scale for the Assessment of Basic Symptoms (BSABS), which is a comprehensive interview schedule that has been translated into several languages, since self-rating questionnaires, with the possible exception of the Frankfurt Complaint Questionnaire, do not necessarily target the qualitative or structural alterations of subjective experiences [5]. Nonetheless, the usefulness of the BSABS as a screening measure for the early detection of schizophrenia should be evaluated in studies using general population with a large sample size to allow for naturalistic sampling [6].
Subjective experience is not an observable one. However, such experience is considered to be a fundamental feature of schizophrenia-spectrum disorders [7,8] and thus may represent a potentially important trait phenotype although disturbances of subjective experiences are poorly considered in the current diagnostic system. The issue of fine-grained clinical assessment is always at the forefront of the modellization of the vulnerability to schizophrenia.