The schizophrenias as nervous types

Attenuated Post-Movement Beta Rebound Associated With Schizotypal Features in Healthy People

INTRODUCTION

Schizophrenia and schizotypal personality disorder (SPD) lie on a single spectrum of mental illness and converging evidence suggests similarities in the etiology of the 2 conditions. However, schizotypy is a heterogeneous facet of personality in the healthy population and so may be seen as a bridge between health and mental illness. Neural evidence for such a continuity would have implications for the characterization and treatment of schizophrenia. Based on our previous work identifying a relationship between symptomology in schizophrenia and abnormal movement-induced electrophysiological response (the post-movement beta rebound [PMBR]), we predicted that if subclinical schizotypy arises from similar neural mechanisms to schizophrenia, schizotypy in healthy individuals would be associated with reduced PMBR.

METHODS

One-hundred sixteen participants completed a visuomotor task while their neural activity was recorded by magnetoencephalography. Partial correlations were computed between a measure of PMBR extracted from left primary motor cortex and scores on the Schizotypal Personality Questionnaire (SPQ), a self-report measure of schizotypal personality. Correlations between PMBR and SPQ factor scores measuring cognitive-perceptual, interpersonal and disorganization dimensions of schizotypy were also computed. Effects of site, age, and sex were controlled for.

RESULTS

We found a significant negative correlation between total SPQ score and PMBR. This was most strongly mediated by variance shared between interpersonal and disorganization factor scores.

CONCLUSION

These findings indicate a continuum of neural deficit between schizotypy and schizophrenia, with diminution of PMBR, previously reported in schizophrenia, also measurable in individuals with schizotypal features, particularly disorganization and impaired interpersonal relations.

Paracingulate Sulcus Morphology and Hallucinations in Clinical and Nonclinical Groups

Hallucinations are a characteristic symptom of psychotic mental health conditions that are also experienced by many individuals without a clinical diagnosis. Hallucinations in schizophrenia have been linked to differences in the length of the paracingulate sulcus (PCS), a structure in the medial prefrontal cortex which has previously been associated with the ability to differentiate perceived and imagined information. We investigated whether this putative morphological basis for hallucinations extends to individuals without a clinical diagnosis, by examining whether nonclinical individuals with hallucinations have shorter PCS than nonclinical individuals without hallucinations. Structural MRI scans were examined from 3 demographically matched groups of individuals: 50 patients with psychotic diagnoses who experienced auditory verbal hallucinations (AVHs), 50 nonclinical individuals with AVHs, and 50 healthy control subjects with no life-time history of hallucinations. Results were verified using automated data-driven gyrification analyses. Patients with hallucinations had shorter PCS than both healthy controls and nonclinical individuals with hallucinations, with no difference between nonclinical individuals with hallucinations and healthy controls. These findings suggest that the association of shorter PCS length with hallucinations is specific to patients with a psychotic disorder. This presents challenges for full-continuum models of psychosis and suggests possible differences in the mechanisms underlying hallucinations in clinical and nonclinical groups.

Testing continuum models of psychosis: No reduction in source monitoring ability in healthy individuals prone to auditory hallucinations

People with schizophrenia who hallucinate show impairments in reality monitoring (the ability to distinguish internally generated information from information obtained from external sources) compared to non-hallucinating patients and healthy individuals. While this may be explained at least in part by an increased externalizing bias, it remains unclear whether this impairment is specific to reality monitoring, or whether it also reflects a general deficit in the monitoring of self-generated information (internal source monitoring). Much interest has focused recently on continuum models of psychosis which argue that hallucination-proneness is distributed in clinical and non-clinical groups, but few studies have directly investigated reality monitoring and internal source monitoring abilities in healthy individuals with a proneness to hallucinations. Two experiments are presented here: the first (N = 47, with participants selected for hallucination-proneness from a larger sample of 677 adults) found no evidence of an impairment or externalizing bias on a reality monitoring task in hallucination-prone individuals; the second (N = 124) found no evidence of atypical performance on an internal source monitoring task in hallucination-prone individuals. The significance of these findings is reviewed in light of the clinical evidence and the implications for models of hallucination generation discussed.

A Cognitive Psychology of Mystical and Altered-State Experience

Traditional approaches to the psychology of religious-mystical and altered-state experience have divided between more psychoanalytic and psychiatric views that associate such experience with “schizophrenia,” “regression,” and “primitivity” and the more intuitive Jungian and transpersonal-humanistic assertions of a “higher” path of development (“self-actualization”). By considering the full range of empirical reports from mystical-meditational, psychedelic, and schizophrenic settings, a “positive” cognitive psychology of the abstract symbolic processes underlying such states is developed—potentially reconciling those divergent approaches, explaining the place of these states at the center of culture in “primitive” and classical societies, and casting a unique light on the normally masked core of semantic processes. Features of the abstract, recombinatory, cross-modal operations posited by Neisser, Arnheim, Mead, and Geschwind as criterial for human symbolic capacity are located within the varieties of altered-state report and Rudolf Otto's phenemonology of the numinous. However, such an analysis only becomes powerful when the ostensibly “primitive,” “negative,” or “withdrawn” aspects of such experience—its association with phylogenetically primitive and defensive “tonic immobility,” the subjective “death” or “annihilation” experience of catatonic schizophrenia, and the “white light of the void realization” in deep meditation—are also shown to be consequences of a specifically human creative capacity based on cross-modal translation between touch, vision, and audition. Religious-mystical experience is a full exteriorization and completion of our cross-modal synaesthetic capacity. Entailing an inherent “abstract” stress, it is defensively impacted in paranoid and chronic schizophrenia. Of the traditional “developmental” models suggesting that religious-mystical experience is a regression to fetal, phylogenetic, or normally masked, ultra-rapid microgenetic/iconic stages, only the latter, as demonstrated by a reinterpretation of classical introspectionist research, is consistent with the abstract cognitive features of such experience and the view that all higher mental processes involve a disassembling and reuse of microgenetically preliminary perceptual and affective patterns. The more “primitive” the sensory quality, the more abstract its potential reference when synaesthetically embodied. Accordingly, the “reality status” of mystical experience is addressed.

Psychotic-like experiences and associated socio-demographic factors among adolescents in China

OBJECTIVE

Adolescents with persistent psychotic-like experiences (PLEs) may be at high risk for later development of psychoses. Exploring early age risk factors for PLEs may provide useful information for prevention of mental disorders and improvement of mental health.

METHOD

A total of 5427 adolescents (aged between 10 and 16) participated in a cross-sectional survey, with social and demographic information collected. The Positive Subscale of Community Assessment of Psychic Experiences (CAPE) was used to measure PLEs, and the CAPE Depressive and Negative Subscales were used to examine depressive and negative experiences. The Trauma History Questionnaire (child version) was used to assess experiences of previous traumatic events.

RESULTS

In our study, 95.7% of the adolescents reported more than one episode of PLEs, while 17.2% reported "nearly always" having PLEs. High positive correlations were shown both between frequency scores among experiences of three dimensions (PLEs, depressive and negative experiences), and between frequency and distress scores. Factors associated with a higher risk for more frequent and distressing PLEs include: urban setting, family history of psychiatric illnesses, and higher impact from previous traumatic events at present.

CONCLUSIONS

Episodes of PLEs are common in Chinese adolescents, however only a small proportion have persistent PLEs, with worsening distress as the frequency increased. PLEs shared similar environmental and genetic risk factors not only with the clinical phenotypes, which is consistent with the continuity model of PLEs, but also with depressive and negative experiences, which may imply etiologic relation between different dimensions of psychosis at the subclinical level.

Examining the Psychosis Continuum

The notion that psychosis may exist on a continuum with normal experience has been proposed in multiple forms throughout the history of psychiatry. However, in recent years there has been an exponential increase in efforts aimed at elucidating what has been termed the 'psychosis continuum'. The present review seeks to summarize some of the more basic characteristics of this continuum and to present some of the recent findings that provide support for its validity. While there is still considerable work to be done, the emerging data holds considerable promise for advancing our understanding of both risk and resilience to psychiatric disorders characterized by psychosis.

An investigation of a novel transdiagnostic model of delusions in a group with positive schizotypal symptoms

INTRODUCTION

Although several theories of delusions have been put forward, most do not offer a comprehensive diagnosis-independent explanation of delusion aetiology. This study used a non-clinical sample to provide empirical support for a novel transdiagnostic model of delusions that implicates aberrant semantic memory and emotion perception processes as key factors in delusion formation and maintenance. It was hypothesised that among a non-clinical sample, people high in schizotypy would demonstrate differences in semantic memory and emotion perception, relative to people low in schizotypy.

METHODS

Using the Cognitive Disorganisation subscale of the Oxford-Liverpool Inventory of Feelings and Experiences, 41 healthy participants were separated into high and low schizotypy groups and completed facial emotion perception and semantic priming tasks.

RESULTS

As expected, participants in the high schizotypy group demonstrated different performance on the semantic priming task and reduced facial affect accuracy for the emotion anger, and reaction time differences to fearful faces.

CONCLUSION

These findings suggest that such processes may be involved in the development of the sorts of unusual beliefs which underlie delusions. Investigation of how emotion perception and semantic memory may interrelate in the aetiology of delusions would be of value in furthering our understanding of their role in delusion formation.

Is disorganization a feature of schizophrenia or a modifying influence: evidence of covariation of perceptual and cognitive organization in a non-patient sample

A subgroup of people with schizophrenia is characterized by reduced organization in perception, thought, language, and motor functioning, and these impairments covary significantly. While this may reflect multiple expressions of an illness-related core processing impairment, it may also represent the extreme end of an organization-disorganization dimension that is found throughout the general population. In this view, disorganization is a modifying influence on illness expression. To obtain preliminary information on this hypothesis, we examined covariation of perceptual and cognitive organization in a non-patient sample. Subjects completed a battery of perceptual tasks with demonstrated sensitivity to schizophrenia and disorganization, and a battery of questionnaires examining cognitive organization. Our results indicated that level of perceptual organization ability, across multiple tasks, was associated with self-reported levels of cognitive organization on multiple measures. This is thus preliminary evidence for a common process affecting perceptual and cognitive organization in the general population, suggesting that disorganization may reflect a modifying influence mechanism, instead of an illness-related process, in schizophrenia.

Genetics, cognition, and neurobiology of schizotypal personality: a review of the overlap with schizophrenia

Schizotypy refers to a set of temporally stable traits that are observed in the general population and that resemble the signs and symptoms of schizophrenia. Here, we review evidence from studies on genetics, cognition, perception, motor and oculomotor control, brain structure, brain function, and psychopharmacology in schizotypy. We specifically focused on identifying areas of overlap between schizotypy and schizophrenia. Evidence was corroborated that significant overlap exists between the two, covering the behavioral brain structural and functional as well molecular levels. In particular, several studies showed that individuals with high levels of schizotypal traits exhibit alterations in neurocognitive task performance and underlying brain function similar to the deficits seen in patients with schizophrenia. Studies of brain structure have shown both volume reductions and increase in schizotypy, pointing to schizophrenia-like deficits as well as possible protective or compensatory mechanisms. Experimental pharmacological studies have shown that high levels of schizotypy are associated with (i) enhanced dopaminergic response in striatum following administration of amphetamine and (ii) improvement of cognitive performance following administration of antipsychotic compounds. Together, this body of work suggests that schizotypy shows overlap with schizophrenia across multiple behavioral and neurobiological domains, suggesting that the study of schizotypal traits may be useful in improving our understanding of the etiology of schizophrenia.

An Overview of the Association between Schizotypy and Dopamine

Schizotypy refers to a constellation of personality traits that are believed to mirror the subclinical expression of schizophrenia in the general population. Evidence from pharmacological studies indicates that dopamine (DA) is involved in the etiology of schizophrenia. Based on the assumption of a continuum between schizophrenia and schizotypy, researchers have begun investigating the association between DA and schizotypy using a wide range of methods. In this article, we review published studies on this association from the following areas of work: (1) experimental investigations of the interactive effects of dopaminergic challenges and schizotypy on cognition, motor control, and behavior (2), dopaminergically supported cognitive functions (3), studies of associations between schizotypy and polymorphisms in genes involved in dopaminergic neurotransmission, and (4) molecular imaging studies of the association between schizotypy and markers of the DA system. Together, data from these lines of evidence suggest that DA is important to the expression and experience of schizotypy and associated behavioral biases. An important observation is that the experimental designs, methods, and manipulations used in this research are highly heterogeneous. Future studies are required to replicate individual observations, to enlighten the link between DA and different schizotypy dimensions (positive, negative, cognitive disorganization), and to guide the search for solid DA-sensitive behavioral markers. Such studies are important in order to clarify inconsistencies between studies. More work is also needed to identify differences between dopaminergic alterations in schizotypy compared to the dysfunctions observed in schizophrenia.

The role of predisposition to hallucinations on non-clinical paranoid vs. socially anxious individuals after hearing negative affective-laden sounds: an experimental investigation

BACKGROUND

Research suggested that negative affective-laden sounds act as environmental stressors that elicit negative affect (Bradley and Lang, 2000a).

AIMS

We tried to test for the role of an interaction between predisposition to hallucinatory experiences and exposure to negative affective laden sounds for the presence of paranoid ideation.

METHOD

We used an experimental design that followed the vulnerability × stress model. We defined three groups from a sample of students: paranoia group vs. social anxiety group vs. control group. Their psychological characteristics were measured through self-reports of paranoia, anxiety, predisposition to hallucinations and depressive symptoms at Time 1 (before the experiment). Participants had to listen to either negative affective laden sounds (e.g. screaming) or positive affective laden sounds (e.g. sound of ocean waves). Their paranoid ideation and positive vs. negative emotional reactions to sounds were measured through self-reports at Time 2 (after the experiment).

RESULTS

Data showed that the paranoia group presented more serious psychological vulnerabilities than the social anxiety group. A MANCOVA also showed that the independent variables ("group" and "experimental sound conditions") had statistically significant main effects on general paranoia ideation at Time 2. Furthermore, there was a significant three-way interaction between group x predisposition to hallucinatory experiences × experimental condition of sounds for the presence of general paranoid ideation at Time 2. Limitations included the small sample size and the effects of parasite variables, e.g. noise.

CONCLUSIONS

Individuals' predisposition for hallucinatory experiences increases the probability of possessing paranoid ideation. This tendency is a characteristic of paranoid non-clinical individuals.

Psychotic experience subtypes, poor mental health status and help-seeking behaviour in a community sample of young adults

BACKGROUND

Different subtypes of psychotic experiences (PEs) have been identified in clinical and non-clinical samples. Researchers have considered these PEs to either be variations of personality or expressions of vulnerability to psychotic disorder. This study aimed to determine which particular subtypes of PEs were more likely to be associated with poor mental health status and help-seeking behaviour in a non-clinical sample of young adults.

METHODS

The study was conducted on a community sample of 997 young adults. The prevalence of PEs and distress was measured using the community assessment of psychic experiences (CAPE), depressive and anxiety symptoms were measured using Beck depression inventory-II and Beck anxiety inventory, and general functioning was measured using the general health questionnaire-12. Factorial analysis of the CAPE positive dimension was conducted and correlations between factors and clinical variables were analysed.

RESULTS

Four PE subtypes were identified: perceptual abnormalities, persecutory ideas (PI), bizarre experiences, and magical thinking. At least one high frequency PI was endorsed by 60.8% (n = 606) of the sample and proved to be significantly associated both with poor mental health status and help-seeking behaviour.

CONCLUSION

PEs subtypes are differentially associated with various markers of poor mental health status. PI seem to have stronger psychopathological significance than other subtypes of PEs. Further longitudinal studies are required to extend these findings.

The prediction of hallucinatory predisposition in non-clinical individuals: Examining the contribution of emotion and reasoning

BACKGROUND

Emotion, especially anxiety, has been implicated in triggering hallucinations. Reasoning processes are also likely to influence the judgments that lead to hallucinatory experiences. We report an investigation of the prediction of hallucinatory predisposition by emotion and associated processes (anxiety, depression, stress, self-focused attention) and reasoning (need for closure, extreme responding).

METHOD

Data were analysed from a questionnaire survey in a student population (N = 327).

RESULTS

Higher levels of anxiety, self-focus, and extreme responding were associated with hallucinatory predisposition. Interactions between these three variables did not strengthen the predictive effect of each. Depression, stress, and need for closure were not found to be predictors of hallucinatory experience in the regression analysis.

CONCLUSION

Emotional and reasoning processes may both need to be considered in the understanding of hallucinatory experience.

The psychosis threshold in Ultra High Risk (prodromal) research: is it valid?

"Transition to psychosis" has been the outcome of interest in Ultra High Risk (UHR) and "prodromal" studies. However, the point at which an individual crosses the line from high risk or prodromal state to psychosis threshold is arbitrary. There have been few attempts to examine whether this threshold has any validity in terms of biological markers or course and outcome. More research is needed to determine if the current point at which a person is declared "psychotic" is valid. Indeed some persons labeled as having developed psychosis may quickly recover. In such a situation their transition could be seen as "trivial". Others who do not make "transition" may have worse outcomes. Validation of the transition point is an important issue as "risk syndrome for psychosis" (psychosis prodrome) is being considered for inclusion in the DSMV. Further, much research attempts to distinguish markers for psychotic disorders by examining the differences between UHR individuals who do and do not develop psychosis. Thus it behooves us not just to have this risk syndrome validated, but to have the hypothetical endpoint of psychosis validated as well.

Attributional biases in paranoia: the development and validation of the Achievement and Relationships Attributions Task (ARAT)

INTRODUCTION

Attributional biases, in particular a tendency to blame other people for negative events, have been reported among people with persecutory delusions and in people in the general population with subclinical paranoia. However, existing attribution measures have some shortcomings. The present study therefore describes the development and validation of a new attribution measure: the Achievement and Relationships Attributions Task (ARAT). The ARAT assesses attributional style in a range of everyday life situations related to achievement and interpersonal events, and provides a context for attributions. Each scenario has three possible causes embedded within it: internal, personal-external, and situational-external.

METHODS

Three hundred and fifteen healthy volunteers completed the ARAT and measures of paranoia and depression.

RESULTS

A tendency to blame other people rather than themselves was associated with high trait paranoia and multidimensional aspects of paranoid beliefs. Depression was associated with a decreased tendency to internalise success.

CONCLUSIONS

The ARAT is a valid measure of attributional style in relation to paranoid ideation in a nonclinical population and has good interrater reliability.

Psychotic-like experiences in a community sample of adolescents: implications for the continuum model of psychosis and prediction of schizophrenia

OBJECTIVE

Studies conducted in community samples suggest that psychotic-like experiences are common in the general population, leading to suggestions that they are either variations of normal personality or are different expressions of underlying vulnerability to psychotic disorder. Different types of psychotic symptoms may exist, some being normal variants and some having implications for mental health and functioning. The aim of the present study was to determine if different subtypes of psychotic-like experiences could be identified in a community sample of adolescents and to investigate if particular subtypes were more likely to be associated with psychosocial difficulties, that is, distress, depression and poor functioning, than other subtypes.

METHOD

Eight hundred and seventy-five Year 10 students from 34 schools participated in a cross-sectional survey that measured psychotic-like experiences using the Community Assessment of Psychic Experiences; depression using the Centre for Epidemiologic Studies Depression Scale; and psychosocial functioning using the Revised Multidimensional Assessment of Functioning Scale. Factor analysis was conducted to identify any subtypes of psychotic experiences.

RESULTS

Four subtypes of psychotic-like experiences were identified: Bizarre Experiences, Perceptual Abnormalities, Persecutory Ideas, and Magical Thinking. Intermittent, infrequent psychotic experiences were common, but frequent experiences were not. Bizarre Experiences, Perceptual Abnormalities and Persecutory Ideas were strongly associated with distress, depression and poor functioning. Magical Thinking was only weakly associated with these variables. Overall these findings may suggest that infrequent psychotic-like experiences are unlikely to be a specific risk factor for onset of a psychotic disorder in community samples.

CONCLUSIONS

Given that the different subtypes had varying associations with current difficulties it is suggested that not all subtypes confer the same risk for onset of psychotic disorder and poor outcome. Bizarre Experiences, Perceptual Abnormalities and Persecutory Ideas may represent expressions of underlying vulnerability to psychotic disorder, but Magical Thinking may be a normal personality variant.

Validation of the English and French versions of the Community Assessment of Psychic Experiences (CAPE) with a Montreal community sample

OBJECTIVE

The aim of this study was to examine the reliability, validity and factor structure of the Community Assessment of Psychic Experiences (CAPE), a 42-item self-report questionnaire. We analyzed the internal consistency of the CAPE to determine whether the 3-factor structure (positive, negative and depressive symptoms) found by the CAPE authors would also be found in our sample.

METHOD

A sample of 2275 individuals from the general community in the Montreal area completed the questionnaire in either French or English.

RESULTS

The internal consistencies of the original three subscales were good and the confirmatory factor models had a good fit. The exploratory factor analysis suggested a 3-5-factor solution, without improving the alternative factor structures. The 4-factor solution separated positive symptoms into factors we called 'bizarre positive symptoms' and 'social delusions', and the 5-factor solution separated positive symptoms further and included a 'popular psychic beliefs' factor. Results suggest that the scalability might be improved by shortening the original questionnaire to 23 items with the same 3 original scales.

CONCLUSION

We support the internal consistency of the CAPE. Although alternative scaling (4 and 5 factors) did not improve the model fit, researchers interested in distinguishing 3 factors of positive symptoms could find utility in these two new scales. Finally, reducing the number of CAPE items could be useful for shorter surveys. Future studies should test the implications of these suggestions.

Normalizing psychotic symptoms

Individuals in random community samples not diagnosed as mentally ill report a variety of mental states along a continuum from 'normalcy' to psychosis. The existence of this continuum suggests that in addition to hallucinations and delusions, other more subtle reflections of psychotic thought processes might occur in ordinary mental life. Five transient disruptions of ordinary mental life which may mirror the cognitive processes underlying psychosis are identified. Thought experiments designed to heighten awareness of each of these states are described. The thought experiments aim at helping clinicians 'normalize' psychotic symptoms by locating analogies to psychosis in their own mental life. In addition, a questionnaire was administered to subjects in a random community sample to assess the frequency of the transient disruptions explored in the exercises in the general population. These disruptions appear to be quite common. This would suggest that at least some psychotic symptoms are a pathological expression of psychological processes latent in and widely distributed throughout the general population

The influence of schizotypy traits on prepulse inhibition in young healthy controls

Deficits in sensorimotor gating or prepulse inhibition (PPI) have been demonstrated repeatedly in patients with schizophrenia or with schizotypal personality disorder, but not consistently in schizotypal non-psychiatric controls. The appearance of normal PPI in this group has been interpreted as reflecting a discontinuous underlying vulnerability to psychosis in high-risk groups. An alternative interpretation is that underlying vulnerability to psychosis is continuously distributed in the normal population (Claridge, 1972, 1987), and therefore that performance on information processing tasks should vary continuously with increasing levels of schizotypy in non-clinical populations. We attempted to examine further the notion of a continuous relationship between PPI and schizotypy in 44 (17 female, 27 male) healthy, non-smoking subjects controlling for menstrual phase. In this selected sample, the findings do not support a continuum model, and suggest that PPI deficits may indeed be the result of a discontinuous neurophysiological change in those with psychotic illness, rather than one continuously distributed in the normal population.

Analyse der Schizophreniespezifität schizotypischer Fragebogenskalen

Zusammenfassung. Die Untersuchung schizotyper Symptome hat sich in den vergangenen Dekaden als methodisch alternativer Zugang der Schizophrenieforschung etabliert. Entgegen der Annahme, dass die Schizotypie phäno- aber auch genotypisch spezifisch mit der Schizophrenie assoziiert ist, haben verschiedene Fragebogen-Studien zeigen können, dass psychiatrische Kontrollen ähnlich hohe Werte in Instrumenten zur Erfassung der Schizotypie erreichen wie schizophrene Patienten. Zielsetzung der vorliegenden Studie war der Vergleich schizophrener, depressiver, zwangserkrankter und gesunder Personen in verschiedenen Skalen, die auf den Schizotypiedefinitionen von Meehl, Claridge sowie dem DSM beruhen. Schizophrene erzielen zwar höhere Werte in positiv-symptomatischen Schizotypieskalen, weisen aber niedrigere Ausprägungen auf in allen negativ-symptomatischen, desorganisierten und Basissymptomskalen im Vergleich zu mindestens eine der psychiatrischen Kontrollgruppen. Bei etwa 25% der Items konnten keinerlei Gruppenunterschiede gefunden werden. In einem weiteren Schritt wurde eine schizophrenie-nahe Schizotypieskala bestehend aus 24 v.a. positiv-symptomatischen Items komponiert, in denen Schizophrene wenigstens auf statistischem Trend-Niveau höhere Werte als die Kontrollen erzielen. Die Prüfung der prädiktiven Validität dieser Skala ist Ziel zukünftiger Forschungsanstrengungen.

Paradigm failure in functional psychosis: review and implications

Increasing sophistication in the neurosciences has re-stimulated expectations that the underlying biological mechanisms involved in the psychoses might finally be clarified. These expectations however coexist with a sense of mounting frustration over the continuing failure of such progress to occur. One important factor in this failure is an enduring reliance upon obsolete nosological concepts and tools. The persistence of concepts such as schizophrenia and manic-depressive illness, which are substantially based upon unsustainable assumptions concerning the relationship between pathophysiology, symptoms and outcome, interferes with the appropriate deployment of new technologies and the interpretation of the resulting data. As many have suspected for some time, we are in a state of chronic paradigm failure, yet the lack of a superior alternative makes it difficult to dispense with traditional concepts. Following a review of the principal nosological paradigms, it is argued that the psychopathology of psychosis is more fluid than acknowledged by the dominant neo-Kraepelinian paradigm in particular. An alternative, which may be termed the loose linkage model, is proposed, which though it falls short of full paradigm status, does represent more accurately the true state of affairs in psychotic disorder, with fewer historical preconceptions. Its importance lies particularly in its significance for research strategy, and its capacity to minimise early iatrogenic sequelae of the diagnostic process and permit a more honest approach to clinical care.

'The schizophrenias as nervous types' revisited

In 1972 the author proposed that schizophrenia represents an aberration of central nervous processes that underlie cognitive and personality characteristics which can be observed in many healthy people. The present paper brings the evidence for that theory up to date and concludes that over the past 15 years it has received considerable empirical support. The way in which the theory confronts the question of whether or not schizophrenia is a disease is also clarified.

Psychoticism and creativity

Eysenck and Eysenck (1976) cited a number of studies showing that creativity and originality are associated with high scores on their Psychoticism factor, P. In this study, we examined the generality of this claim by using a different set of creativity measures, scales from the Comprehensive Ability Battery (Hakstian & Cattell, 1976) and the Eysenck Personality Questionnaire (Eysenck & Eysenck, 1975), with a sample of 173 students. No appreciable overlap was found between the creativity scales and P. A number of possible explanations for this result are discussed, and we concluded that this finding may cast doubt on the generality of the link between creativity and P.

Do positive symptom and negative symptom subtypes of schizophrenia show qualitative differences in language production?

The present study examined a prominent symptom subtype conception of the psychopathology of schizophrenia. It analysed the presumed dichotomy between hallucinations, delusions and formal thought disorder as positive symptoms and flattening of affect and poverty of speech as negative symptoms, and tested predictions concerning the nature of the mediating processes of positive and negative symptoms. Four different analyses were applied to the transcripts of speech produced by 9 normals, 10 chronic schizophrenics with only positive symptoms of whom 7 had incoherence of speech, and 9 chronic schizophrenics with only negative symptoms of whom 4 had poverty of speech. The conception of the nature of the mediating processes of positive and negative symptoms was not supported by the results. Further, a clear dichotomy between positive and negative symptom groups was not shown to exist, because positive speech disorder and negative speech disorder did not follow the presupposed dichotomy. Thus, contrary to existing conceptions of speech disorder in schizophrenia, both positive and negative speech disorder are marked by poverty of thought, as measured by the production of fewer and shorter ideas and lower speech variability.

Covariation between two-flash threshold and skin conductance level in first-breakdown schizophrenics: relationships in drug-free patients and effects of treatment

Earlier research suggested that, compared with other individuals, schizophrenics show a different form of covariation between electrodermal level and perceptual discrimination, as indexed by the two-flash threshold. However, dispute has arisen as to whether previous contradictory results obtained on patient samples can be explained by a conventional inverted-U function or whether the relationship takes on an entirely different form, i.e., a U function. The latter alternative was confirmed here in a study of first-breakdown drug-free schizophrenics, tested on 3 consecutive days after hospital admission and before treatment began. However, the U function was evident only in the larger of two subgroups of schizophrenics, identified as patients whose treatment was delayed longer after admission, who were clinically less emotionally responsive and who, in basic personality, were more introverted. When the patients were subsequently tested during treatment, no systematic relationship between two-flash threshold and skin conductance could be discerned. The latter presumably reflected the fact that, during this phase of the experiment, there were marked and complex changes in the individual measures, the effects of treatment on which were briefly examined.

Loudness judgments, evoked potentials, and reaction time to acoustic stimuli early and late in the cardiac cycle in chronic schizophrenics

Two experiments were performed to test Broen's (1968) theory that chronic schizophrenics show increased sensitivity of the inhibitory mechanisms assumed to follow cardiovascular baroreceptor stimulation. Subjects were chronic schizophrenics and normals matched for age and education. In Experiment I reaction times, vertex potentials, and loudness judgments to single tones presented during systole or diastole were analyzed. Contrary to expectation, schizophrenics more often judged tones presented during systole to be louder than tones presented during diastole; the opposite was true for normals. A similar pattern was found in Experiment II, where pairs of tones were presented instead of single tones. No influence of cardiac cycle on reacion time or evoked potentials emerged. Results do not support Broen's assumption.

High dose diazepam in schizophrenia

The pharmacological properties and the equivocal antipsychotic effects of diazepam reported in the literature suggested the use of high doses of this drug on schizophrenic patients to re-evaluate its usefulness. Treatment of 15 schizophrenic patients with doses of up to 400 mg/day showed a specific effect on hallucinations and certain forms of delusion. One group (nine patients with paranoid-hallucinatory and one with schizo-affective psychosis) showed a significant reduction in psychopathology as documented in the Brief Psychiatric Rating Scale (BPRS) and the Global Clinical Impressions (GCI), whereas five other patients (all of the schizo-affective type with symptoms of depression, euphoria, and/or psychotic anxiety) did not respond and had to be withdrawn from the study. Under the treatment an absence of sedative effects and a development of the feeling of well-being and euphoria were noticed. In three patients with doses of over 260 mg/day a marked loss of inhibitions in sexual and social behaviour was observed. It is concluded that high doses of diazepam may be useful in certain types of schizophrenia.

Comparison of spontaneous and contraceptive menstrual cycles on a visual discrimination task

21 women with spontaneous ovulatory menstrual cycles, and 7 women who were regular users of oral contraceptives were investigated over two consecutive menstrual cycles. There two groups were compared on their two flash threshold performance and on mood ratings. It was found that, for women with ovulatory menstrual cycles, visual sensitivity was enhanced during the late follicular phase of the cycle, as ovulation approached. At other phases of the menstrual cycle (paramenstrual and luteal) visual sensitivity remained constant and comparable to the values found in women who were taking to the values found in women who were taking contraceptives. Women who were taking contraceptives showed no significant variation in visual sensitivity with phase of the menstrual cycle. The overall level of anxiety, as reflected by mood ratings was higher in women with spontaneous cycles compared to those taking contraceptives. Neither group, however, showed significant variation in anxiety with phase of the cycle.

A curvilinear relationship between extraversion and performance for adult retardates

A curvilinear relationship between extraversion and performance on an operant task for retarded adults was hypothesized. Following previous research with subjects with disturbed cognitive processes, the curve was hypothesized to be opposite from the usual Yerkes-Dodson relationship. The Eysenck-Withers Personality Inventory Extraversion scale was orally administered to 20 adult retardates. These subjects were then required to push a button on either the left or right side for M&M candies. The side that was reinforced changed five times. The number of errors made after the changes indicated the quality of performance. A significant curvilinear relationship between extraversion and errors was found, with moderately introverted subjects making more errors than either extremely introverted or extraverted subjects.