Clinical detection of schizophrenia-prone individuals: Critical appraisal

Issues that undermine the early detection of schizophrenia includean inadequate grasp of the construct validity of the conceptof schizophrenia, insufficient conceptualisation of psychosisand of the illness onset, and a general lack of a theoreticalframework for psychopathology. Subjective experience is emphasisedas a potentially promising domain for future research.

INTRODUCTION

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INTRODUCTION

This article focuses on the limitations of contemporary psychopathology which appear to diminish the feasibility of early detectionand prevention of the schizophrenia-spectrum disorders. Basically,there are three options for early intervention: (a) interveningearly in the course of psychosis, to reduce its duration andpotential sequelae; (b) intervening in the ‘prodromal’phase, to prevent or defer the onset of psychosis and/or attenuateits course; and (c) primary prevention, through reducing the prevalence of potential risk factors (e.g. obstetric complications).This paper discusses the first two issues only and abstainsfrom epidemiological considerations on the flexibility of detectionprogrammes and from a critical appraisal of the rationale behindsuch programmes.

Several psychopathological issues merit attention. First, schizophrenia remains a ‘fuzzy’ scientific concept. For example,the so-called polydiagnostic studies (e.g. comparing DSM–III (American Psychiatric Association, 1980), research diagnosticcriteria with other, equally reasonable definitions of schizophrenia)consistently demonstrate that the number of patients with schizophreniadiagnosed in a given sample varies by a factor of 2–3,2–3, depending on the diagnostic criteria applied andthe composition of the examined sample (Jansson et al, 2002).The official endorsing of the DSM–III concept of schizophreniaand its contemporary permutations (DSM–IV (American Psychiatric Association, 1994)and ICD–10 (World Health Organization, 1993))was not so much motivated by its superior validity (asyounger colleagues believe), but was founded by a pragmaticconsensus. In a polydiagnostic scenario, a patient diagnosedas being ‘pre-onset’ by one diagnostic system maybe already considered as ‘post-onset’ by anothersystem. This notorious ‘fuzziness’ of the schizophreniaconcept makes dating the illness onset not only a psychometricproblem, but a theoretical issue intimately associated withthe conceptual validity of schizophrenia, that is, what we conceptualiseor take schizophrenia to be in the very first place (see Kendler, 1990).Evidence is available suggesting that onset dating ispractically impossible in nearly half of those with schizophrenia(Fenton & McGlashan, 1991).

PSYCHOSIS PREVENTION

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PSYCHOSIS PREVENTION

However, since we are here mainly concerned with the feasibilityof psychosis prevention, it may seem that the notion of psychosis,at least, is clear-cut, defining a full-blown illness, andtherefore pragmatically more useful than the notion of schizophrenia.Unfortunately, the concept of psychosis is theoretically (phenomenologically)not analysed in the DSM and ICD and therefore not adequatelydefined, apart from a brief list of ostensive indicators (e.g.delusions, hallucinations). There is no conceptualisation of the alterations of human subjectivity (i.e. self-awareness,relatedness to the world, and relatedness to others) that thenotion of psychosis appears to convey at a naïve-inituitivelevel. This is a serious lacuna indeed because the very rationalefor early therapeutic intervention rests on the assumptionthat untreated psychosis exerts toxic effects on the brain (McGlashan & Johannesen, 1996).Given this conceptual lacuna, however,it appears incomprehensible that certain beliefs should bemore dangerous to the brain than other beliefs, that is, amental state harbouring a false (delusional) rather than aconventional belief should be neurotoxic. This conceptual shortfallbecomes of especial clinical significance in the encounter with young patients with insidious onset, marked by the alterationsof conduct and personal world-views, but without hallucinationsand clear-cut circumscribed delusions.

PRODROMAL PHASE INTERVENTION

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PRODROMAL PHASE INTERVENTION

The feasibility of prodromal case identification (in non-clinicaland clinical samples) is currently negligible because we largelyignore the pre-onset phenotypes strongly predictive of laterschizophrenia. The behavioural ‘negative symptoms’are for that purpose prohibitively common (McGorry et al, 1995)and ‘without exploring subjective experience, [they] lackthe specificity necessary to predict future schizophrenia’ (Weiser et al, 2001, p. 962). Whereas it is true that negativesymptoms were once regarded as the diagnostic indicators ofthe schizophrenia-spectrum disorders, this diagnostic specificitywas believed only to emerge upon a more encompassing gestalt, indicative of profound distortions of the patient’s subjectivity (Parnas et al, 2002). In the process of operationalisation,they were stripped of their subjective experiential significanceand transformed into non-specific behavioural deficits (e.g.a-logia, a-volition, a construal misrepresenting the patient’ssubjective perspective, often populated by quite ‘positive’anomalies of experience: Kring et al, 1993; Danion et al, 2001).

In consequence, only intermittent or low-intensity (‘attenuated’)psychotic features are the current candidate symptoms for predictinga future full-blown psychosis in first-contact clinical populations(e.g. Miller et al, 2002; McGorry et al, 2002), a predicamentthat is theoretically highly tautological.

SUBJECTIVE PERSPECTIVE

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SUBJECTIVE PERSPECTIVE

The explosion of interest in early intervention has thereforehighlighted better than any possible theoretical critique ofthe contemporary psychopathology, an alarming ignorance ofthe subjective perspectives of pre-schizophrenic and schizophrenicpatients. This ignorance is a consequence of many years’domination of the positivistic–behaviourist epistemicdogma (Parnas & Bovet, 1995) which shuns subjectivity asits core belief. Entire domains of anomalous experience, highlyrelevant to early differential diagnosis, have vanished fromthe accepted body of clinical knowledge (e.g. anomalies of self-awareness,identity, temporality, varieties of delusional experience, subtleanomalies in affective, perceptual and cognitive experience),in part also because they cannot be addressed in a simplisticlay vocabulary disconnected from any comprehensive accountof human subjectivity. If forced to deal with the subjectivedimension none the less, psychiatry has only a commonsensicaloption at its disposal, in which subjectivity is treated ona par with the spatial objects of the natural world, that is,subjective experience is believed to be describable in thesame way that we describe a stone (Parnas & Zahavi, 2002).Many existing early detection programmes follow a simplifiedmedical model (e.g. advertising for potential patients by publicisinglists of ‘signal symptoms’), which assumes thatthe self of the patient, on the one hand, and his or her symptoms,on the other are independent entities (as e.g. in tuberculosis),but which is rather infrequent at the onset of schizophrenia.The onset of schizophrenia is often associated with profoundalterations of subjective experience that may modify the patient’sworld-view in the ontological sense and motivate a quest formetaphysical meaning that cannot be adequately addressed inthe medical model terms.

Phenomenologically informed empirical studies, paying attentionto anomalies of subjective experience in early schizophreniaand in schizotypal conditions, appear therefore as a promisingresearch direction in the context of early detection. One groupof such studies, initiated in Germany, is the ‘basicsymptoms’ research, which targets non-psychotic experientialanomalies of affectivity, cognition–perception and body–motorexperience. In a 10-year follow-up of a highly selected clinicalsample (suspected of having the potential for schizophrenia),these symptoms predicted subsequent development of schizophreniawith remarkable accuracy (Klosterkötter et al, 2001).These results are obviously in need of replication in morerepresentative clinical samples. Another, overlapping symptom dimension consists of anomalies of self-experience. These anomaliespre-date the onset of schizophrenia, occur in the schizotypalconditions and differentiate schizophrenia from the psychoticbipolar illness (Parnas et al, 1998, 2003; Møller & Husby, 2000;Parnas & Handest, 2003). Guided byphenomenological considerations, it has been recently proposedthat alterations of self-awareness constitute the phenotypic core of schizophrenia-spectum disorders (Sass & Parnas, 2003).Self-anomalies comprise unstable first-person perspectivewith varieties of depersonalisation, disturbed sense of ownershipand agency of experience and action, fluidity of the basicsense of identity, distortions of the stream of consciousnessand experiences of disembodiment. Our group at Hvidovre Hospital is finalising an English version of a psychometric instrumenttargeting these phenomena. However, these symptoms are notsuited to rapid, structured screening by non-clinicians, becausereliable eliciting and evaluating of these phenotypes requirepsychopathological sophistication, interviewing skill and considerabletraining.

CONCLUSION

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CONCLUSION

The limitations of current clinical knowledge constitute a sufficient reason for not launching large-scale societal programmes forearly detection and intervention in schizophrenia. Rather,they should serve as an imperative for further research. However,there is already tremendous room for improvement of ordinarydiagnostic practices. Thus, a majority of first-admission schizophrenia-spectrumpatients examined in our studies had one or several pre-admissionpsychiatric outpatient contacts (e.g. a general practitioneror practising psychiatrist). These patients were usually diagnosedas suffering from affective disorders and offered ineffective treatments. We need to teach mental health professionals howto use our limited clinical resources optimally in order toenhance the accuracy of diagnosis at these crucial early contacts.

REFERENCES

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