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Reviews/Mini-reviews Information Processing and Attentional Dysfunctions as Vulnerability Indicators in Schizophrenia Spectrum Disorders Rikke Bredgaard and Birte Y. Glenthøj 5 Stress, Depression and the Activation of the Immune System Brian Leonard 17 A Review of 19 Double-Blind Placebo-Controlled Studies in Social Anxiety Disorder (Social Phobia) Marcio Versiani 27 Original Investigations/Summaries of Original Research The Genetic Heterogeneity of "Schizophrenia" Helmut Beckmann and Ernst Franzek 35 Viewpoints Reappraisal of Dementia Praecox: Focus on Clinical Psychopathology Carlos Roberto Hojaij 43 Case Reports/Case Series Psychopathological Changes Preceding Motor Symptoms in Huntington's Disease: A Report on Four Cases Benedikt Amann, Andrea Sterr, Heike Thoma, Thomas Messer, Hans-Peter Kapfhammer and Heinz Grunze 55 Amantadine-Induced Multiple Spike Waves on an Electroencephalogram of a Schizophrenic Patient Katsuya Ohta, Eisuke Matsushim, Masato Matsuura, Michio Toru and Takuya Kojima 59 World J Biol Psychiatry (2000) 1, 5 - 15 L REVIEW/MINI-REVIEW Information Processing and Attentional Dysfunctions as Vulnerability Indicators in Schizophrenia Spectrum Disorders Rikke Bredgaard and Birte Y. Glenthøj University of Copenhagen, Department of Psychiatry, Bispebjerg Hospital, Copenhagen, Denmark Summary Introduction The schizotypal personality disorder is believed to The theory of a schizophrenic spectrum be part of the schizophrenic spectrum of disorders originates from the observation that including schizophrenic patients as well as some of schizophrenics and schizotypal disordered their seemingly unaffected relatives with discreet subjects share common clinical traits, and from symptoms. Spectrum-individuals are characterised genetic studies which have documented an by a genetic vulnerability for schizophrenia. The etiologic relationship (Parnas 1997). The vulnerability is connected with neurocognitive spectrum encompasses a continuum of deficits independent of clinical state. Some cognitive conditions ranging from severe, unremitting dysfunctions are unspecific and probably related to psychotic schizophrenia to milder, episodic non-genetic brain damage. A consistent finding has, psychotic schizophrenia-like disorders and however, been poor performance in tasks involving discreet defects in reality testing and cognitive information processing and attention. The findings function in seemingly unaffected relatives to point to the existence of specific sensory-perceptual schizophrenic patients or patients with deficits or a general attentional dysfunction. schizotypal personality disorder (Braff 1993). Identification of cognitive disturbances characteristic not only of schizophrenics, but also of The schizotypal personality disorder is schizotypal disordered and their relatives in the characterised by a schizophrenia-like boundaries of schizophrenia, is relevant in order symptomatology without psychotic depth. better to understand the pathogenetic mechanisms Patients show odd thinking and speech, and treatment of schizophrenia. In the present inappropriate or constricted affect, autistic review clinical data are analysed based on models features, unusual perceptual experiences and of vulnerability and information processing with pseudo-obsessions. Particularly in response to reference to a characterisation of the neuro- stress they might experience micro-psychotic integrative deficits that form the core abnormalities episodes with intense illusions, hallucinations of the spectrum. and delusions (DSM-IV; ICD-10). The disorder is chronic although 60% never get in contact with Key words: schizotypal personality disorder, the psychiatric system. Only a small proportion schizophrenic spectrum, vulnerability, information of the patients eventually develops processing, attention. schizophrenia (Parnas 1997; ICD-10). Correspondence: Cognitive1 impairments have been considered Birte Y. Glenthøj to be core features of schizophrenia since Dept. of psychiatry E Kraepelin and Bleuler (Braff 1990, 1992, 1993; University Hospital Bispebjerg Dawson et al 1995; Goldberg and Gold 1995). Bispebjerg Bakke 23 Numerous cognitive tasks have confirmed the DK-2400 Copenhagen NV existence of specific problems involving aspects Denmark of memory, imagining, judging, concentration, Tel: + 45 35312315 generating and executing plans, attention2, and Fax: + 45 35313953 information processing3 (Braff 1981, 1993; E-mail: [email protected] Dawson et al 1995; Goldberg and Gold 1995; Nuechterlein and Dawson 1984). Over the last decades there has been a growing interest in elucidating cognitive markers, which hypothetically constitute a common character 1. The term cognition refers to intellectual activities including perceiving, remembering, imagining, conceiving, understanding, reasoning and judging (5). 2. Attention refers to the ability to consciously focus on a particular internal or external experience (1). 3. Information processing refers to the entire range of mental processes that an external sensory stimulus passes through as it enters the central nervous system. It involves identification and classification of information and its source, assessment of its significance, and comparison of it with other incoming information or that stored in memory. The information may or may not be retained, enter consciousness and/or produce a behavioural response (5). 5 L REVIEW/MINI-REVIEW for individuals in the schizophrenic spectrum. more unspecific deficits. Both conditions Such an identification of a genetic liability or predispose, according to the hypothesis, to vulnerability indicator for schizophrenia is development of secondary disturbances in the relevant in order to define a non-clinical transmitters of the brain and psychosis schizophrenic phenotype, optimise therapeutic (Glenthøj 1995; Glenthøj et al 1993, 1998; strategy, and ultimately achieve a better Glenthøj and Hemmingsen 1997, 1999). They understanding of the etiologic and are believed - together or separately - to pathogenetic mechanism of schizophrenia comprise the vulnerability for development of (Green and Nuechterlein 1999; Andreasen 1997; schizophrenic symptoms. Thus, the "core" of Glenthøj et al 1998; Glenthøj and Hemmingsen the schizophrenias is composed of genetically 1999). determined vulnerability indicators rather than observable clinical symptoms (Green and Using schizotypal disordered patients as a basis Nuechterlein 1999). The environmentally for the identification of cognitive markers for caused impairments are more heterogeneous schizophrenia, instead of schizophrenics, is an and thus less suitable for characterisation of the experimental advantage because the spectrum. It is, however, necessary to take these schizotypals are mostly apsychotic, non- symptoms into consideration as they are partly medicated and non-hospitalised. This identical with disturbances caused by genetic minimises the risk that a given cognitive task disposition. Accordingly, they can influence the performance is determined by psychosis per se, results of the clinical tasks of cognitive medication or institutionalisation instead of a dysfunctions. This has been exemplified by genetic liability for schizophrenia (Braff 1993). Goldberg and colleagues, who studied monozygotic twins (Goldberg and Gold 1995). Several authors have reported attentional and Whether an individual who possesses information processing impairments in genetically determined defects in information schizotypals and other individuals at the border processing and attentional functions develops of schizophrenia (Braff 1993; Lenzenweger et al schizophrenia, depends on both the extent and 1991; Nuechterlein and Dawson 1984; the character of the environmental factors, and Nuechterlein et al 1994). Accordingly, these on other genetic factors. dysfunctions are believed to be vulnerability A vulnerability indicator/dysfunction should indicators for schizophrenia (Lenzenweger et al meet the following criteria: 1991). Thus, clarifying attentional and 1. It should be specific for schizophrenic information processing dysfunctions is patients compared to a normal population important for understanding the pathogenesis 2. It should be present in both psychotic and and treatment of schizophrenia and the asymptomatic periods, and schizophrenia-like disorders. 3. It should be disproportionately present in In the present review clinical data are analysed seemingly unaffected first-degree relatives of based on models of vulnerability and schizophrenic patients (Green and information processing, and relevant cognitive Nuechterlein 1999). tasks and task-results are summarised, with Vulnerability indicators can be identified by reference to a characterisation of the neuro- means of three different experimental designs: integrative deficits that form the core 1. By testing schizophrenic patients for stable, abnormalities of the spectrum. symptom-independent dysfunctions 2. By testing first degree relatives of Theories of vulnerability schizophrenics for a disproportional A genetic predisposition is a necessary, but not presence of dysfunctions sufficient, condition for the development of 3. By testing schizotypal disordered patients schizophrenia. The predisposition is supposed (Green and Nuechterlein 1999). to be composed of one or more defective genes that cause a vulnerability for development of Stable vulnerability indicators refer to deficits, schizophrenia because they induce a which presumably are associated with the dysfunction in the neuro-integrative