Schizophrenia

The etiology of schizophrenia remains heavily contested despite extensive research, huge quantities of data, and heavy investment in time and material resources around the world. Not only is there little agreement about the causes of this most devastating of psychiatric conditions, but there is disagreement as to whether the condition exists at all as a coherent entity (Bentall 2006). Evolutionary theorists have had the added problem of explaining how a severe mental illness that causes a significant reproductive disadvantage can continue (...) to exist in human populations, where it is claimed to have a uniform prevalence across the world. Many Darwinian formulations have suggested various forms of tradeoffs where the .. (shrink)

The study argues that linguistic/communication dysfunctions present in disorganized schizophrenia may stem, at least in part, from an impaired theory of mind. Using pragmatics and systemic linguistic theory, the study examined speech samples of two disorganized schizophrenic patients and attempted to determine if their communicative failures are because they lack theory of mind in the sense that they do not take into account the interlocutor's mind, i.e., the interlocutor's intentions, dispositions, and knowledge; or because they have a hyper-theory of mind (...) through which they over-attribute mental states to their interlocutor, i.e., assume that their interlocutor has access to their intentions, dispositions, and knowledge. The study indicates that disorganized schizophrenics are unlikely to be characterized as lacking a theory of mind; rather they seem to have a hyper-theory of mind, to which the psychopathological symptoms of hallucinations, delusions of reference and incoherent speech can be attributed. (shrink)

Evolutionary psychiatrists invariably consider schizophrenia to be a paradox: how come natural selection has not yet eliminated the infamous ‘genes for schizophrenia’ if the disorder simply crushes the reproductive success of its carriers, if it has been around for thousands of years already, and if it has a uniform prevalence throughout the world? Usually, the answer is that the schizophrenic genotype is subject to some kind of balancing selection: the benefits it confers would then outbalance the obvious damage it does. (...) In this paper, however, I will show that the assumptions underlying such evolutionary accounts of schizophrenia are at least implausible, and sometimes even erroneous. First of all, I will examine some factual assumptions, in particular about schizophrenia’s impact on reproductive success, its genetics, its history, and its epidemiology. Secondly, I will take a critical look at a major philosophical assumption in evolutionary psychiatric explanations of schizophrenia. Indeed, evolutionary psychiatrists take it for granted that schizophrenia is a natural kind, i.e. a bounded and objectively real entity with discrete biological causes. My refutation of this natural kind view suggests that schizophrenia is in fact a reified umbrella concept, covering a heterogeneous group of disorders. Therefore, schizophrenia, as we now know it, simply doesn’t have an evolutionary history. (shrink)

Although the evidence remains tentative at best, the conception of hallucinations in schizophrenia as being underconstrained perception resulting from intrinsic thalamocortical resonance in sensory areas might complement current models of hallucination. However, in itself, the approach falls short of comprehensively explaining the neurogenesis of hallucinations in schizophrenia, as it neglects the role of external attributional biases, mental imagery, and a disconnection between frontal and temporal areas.

Background. Positive schizophrenic symptoms, especially passivity phenomena, including auditory hallucinations, may be caused by an abnormal sense of agency, which people with schizotypal personality traits also tend to exhibit. A sense of agency asserts that it is oneself who is causing or generating an action. It is possible that this abnormal sense of self-agency is attributable to the abnormal prediction of one’s own movements in motor control. Method. We conducted an experiment using the “disappeared cursor” paradigm in which non-clinical, healthy (...) participants were required to click on a target using an invisible mouse cursor. Prediction error was defined as the distance between the target and the click point. Results. The results showed that schizotypal personality traits, but not depressive or anxious traits, were correlated with deficits in predicting movements of the subjects’ left hand. In particular, auditory hallucination proneness had the strongest relationship with movement prediction error. In this report, we also discuss the error tendency . Conclusions. This finding is in accordance with the idea that passivity phenomena or proneness may be caused by the abnormal prediction of one’s own actions or movements. (shrink)

When participants observed a rubber hand being touched, their sense of touch was activated . While this illusion might be caused by multi-modal integration, it may also be related to empathic function, which enables us to simulate the observed information. We examined individual differences in the RHI, including empathic and schizotypal personality traits, as previous research had suggested that schizophrenic patients would be more subject to the RHI. The results indicated that people who experience a stronger RHI might have stronger (...) empathic and schizotypal personalites simultaneously. We discussed these relationships in terms of self-other representations. (shrink)

Some patients with schizophrenia are not told their diagnosis. The moral, clinical and practical issues involved in telling or not telling the patient are discussed. In some cases a relative is told the diagnosis but not the patient. The implications for the family and clinical outcome are outlined. A case history illustrating some of these issues is presented.

This paper focuses on the phenomenological significance of schizophrenics' auditory hallucinations and begins with the face-to-face relationship in order to describe the schizophrenic experience. Following European psychiatrists like Blackenburg and Tatossian, the authors compare the bracketing of reality in the Husserlian phenomenological reduction with that of the hallucinatory experience. "Hallucinatory epoché" is used to refer to the schizophrenic way to experiencing auditory hallucinations. The problem of intentionality is then discussed, in addition to that of dialogue, internal time, living body, and (...) intersubjectivity. In this way, "voices" appear as a modification of the own inner voice of the hallucinating person. The "other, " at the origin of the "voices, " is described in terms of transparence, the quality of being univocal, and the quality of being a priori in the perfect tense. This other is not an alter ego, "it" is an alius. Descriptions of hallucinatory voices at several levels of experience, that is, at the transcendental and empirical levels along with descriptions at the level of the life-world, may be at the basis of certain modern empirical theories of "voices. " Results obtained from the European phenomenological point of view and Hoffman's findings in the cognitive field are then compared. The authors finally discuss a case of "speech therapy" and argue that a possible avenue for phenomenological research on schizophrenia is to explore narrativity on the basis of single case studies. One of the goals of phenomenological psychiatry is to assist empirical research in finding new relationships between the stories told by the hallucinator-relationships that are presupposed in clinical experience. (shrink)

Recent studies have shown that schizophrenia may be a disease affecting the states of consciousness. The present study is aimed at investigating metamemory, i.e., the knowledge about one's own memory capabilities, in patients with schizophrenia. The accuracy of the Confidence level (CL) in the correctness of the answers provided during a recall phase, and the predictability of the Feeling of Knowing (FOK) when recall fails were measured using a task consisting of general information questions and assessing semantic memory. Nineteen outpatients (...) were paired with 19 control subjects with respect to age, sex, and education. Results showed that patients with schizophrenia exhibited an impaired semantic memory. CL ratings as well as CL and FOK accuracy were not significantly different in the schizophrenic and the control groups. However, FOK ratings were significantly reduced for the patient group, and discordant FOK judgments were also observed more frequently. Such results suggest that FOK judgments are impaired in patients with schizophrenia, which confirms that schizophrenia is an illness characterized by an impaired conscious awareness of one's own knowledge. (shrink)

Subjective reports and theories about memory may have an influence on other beliefs and behaviours. Patients with schizophrenia suffer a wide range of deficits affecting their awareness of daily life, including memory. With the Metamemory Inventory in Adulthood we ascertained patients’ memory knowledge and thoughts about their own cognitive capacities and about several aspects of cognitive functioning: personal capacities, knowledge of processes, use of strategies, perceived change with ageing, anxiety, motivation and mastery. The participants’ ratings were correlated with their intellectual, (...) cognitive and psychiatric data. Patients felt they had a lower capacity and marginally lower mastery over their memory than comparison subjects. They reported less recourse to strategies, and higher levels of memory-related anxiety. However, their knowledge of basic memory processes, motivation to succeed, and perception of ageing effects were similar. So patients with schizophrenia do not suffer a general and non specific impairment of their metacognitive knowledge. (shrink)

A number of cognitive and behavioral variables influence the performance in tasks of theory of mind (ToM). Since two of the most important variables, memory and explicit expression, are impaired in schizophrenic patients, the ToM appears inconsistent in these patients. An ideal instrument of ToM should therefore account for deficient memory and impaired ability of these patients to explicitly express intentions. If such an instrument is developed, it should provide information that can be used not only to understand the pathophysiology (...) but also to monitor patients. (shrink)

Phillips & Silverstein argue that a range of cognitive disturbances in schizophrenia result from a deficit in cognitive coordination attributable to NMDA receptor dysfunction. We suggest that the viability of this hypothesis would be further supported by explicit implementation in a computational framework that can produce quantitative estimates of the behavior of both healthy individuals and individuals with schizophrenia.

The target article presents a model for schizophrenia extending four levels of abstraction: molecules, cells, cognition, and syndrome. An important notion in the model is that of coordination, applicable to both the level of cells and of cognition. The molecular level provides an “implementation” of the coordination at the cellular level, which in turn underlies the coordination at the cognitive level, giving rise to the clinical symptoms.

Language anomalies and left-hemisphere dysfunction are commonly reported in schizophrenia. Additional evidence also suggests differences in the integration of information between the hemispheres. Bilateral gain is the increase in accuracy and decrease in latency that occurs when identical information is presented simultaneously to both hemispheres. This study measured bilateral gain in controls and individuals with schizophrenia using a lexical-decision task where word or non-word judgements were made to letter strings presented in the left visual field , right visual field or (...) bilaterally . Language was not abnormally lateralized in the schizophrenia group. Controls exhibited the expected decrease in latency when words were presented bilaterally. This effect was not observed in the schizophrenia group who were actually disadvantaged in this condition. The lack of bilateral gain in schizophrenia is discussed as arising from differences in the connections between areas in each hemisphere that mediate language. (shrink)

This paper focuses on one of the original moments of the development of the “phenomenological” current of psychiatry, namely, the psychopathological research of Ludwig Binswanger. By means of the clinical and conceptual problem of schizophrenia as it was conceived and developed at the beginning of the twentieth century, I will try to outline and analyze Binswanger’s perspective from a both historical and epistemological point of view. Binswanger’s own way means of approaching and conceiving schizophrenia within the scientific, medical, and psychiatric (...) context of that time will lead us to grasp the epistemological stakes at the origins of his project of reforming psychiatry by means of phenomenology. I will finally attempt to upgrade and update Binswanger’s project in light of the current reappraisal of phenomenology within the ongoing debate on psychopathology engaged by studies in the field of science and philosophy of mind. (shrink)

A “multifactorial” model should accommodate a psychological perspective, aiming to relate the phenomenology of complex visual hallucinations not only to neurobiological findings but also an understanding of the patient's psychological problems and situation in life. Greater attention needs to be paid to the role of the “lack of insight” patients may have into their hallucinations and its relationship to cognitive impairment.

Based on recent insight into the thalamocortical system and its role in perception and conscious experience, a unified pathophysiological framework for hallucinations in neurological and psychiatric conditions is proposed, which integrates previously unrelated neurobiological and psychological findings. Gamma-frequency rhythms of discharge activity from thalamic and cortical neurons are facilitated by cholinergic arousal and resonate in networks of thalamocortical circuits, thereby transiently forming assemblies of coherent gamma oscillations under constraints of afferent sensory input and prefrontal attentional mechanisms. If perception is based (...) on synchronisation of intrinsic gamma activity in the thalamocortical system, then sensory input to specific thalamic nuclei may merely play a constraining role. Hallucinations can be regarded as underconstrained perceptions that arise when the impact of sensory input on activation of thalamocortical circuits and synchronisation of thalamocortical gamma activity is reduced. In conditions that are accompanied by hallucinations, factors such as cortical hyperexcitability, cortical attentional mechanisms, hyperarousal, increased noise in specific thalamic nuclei, and random sensory input to specific thalamic nuclei may, to a varying degree, contribute to underconstrained activation of thalamocortical circuits. The reticular thalamic nucleus plays an important role in suppressing random activity of relay cells in specific thalamic nuclei, and its dysfunction may be implicated in the biological vulnerability to hallucinations in schizophrenia. Combined with general activation during cholinergic arousal, this leads to excessive disinhibition in specific thalamic nuclei, which may allow cortical attentional mechanisms to recruit thalamic relay cells into resonant assemblies of gamma oscillations, regardless of their actual sensory input, thereby producing an underconstrained perceptual experience. Key Words: Charles Bonnet syndrome; gamma oscillations; hallucinations; late paraphrenia; Lewy body dementia; perception; schizophrenia; thalamocortical system. (shrink)

The commentators provide a wealth of additional neurobiological data that ought to be integrated in a comprehensive model. This response article, however, focuses on clarification of conceptual queries, thereby outlining the proposed theory of hallucinations more sharply, discussing its relationship with schizophrenia, and explaining why underconstrained thalamocortical activation may well be a candidate mechanism responsible for acute schizophrenic symptoms other than hallucinations.

Schizophrenia is a severe mental illness, which affects sense of identity. While the ability to have a coherent vision of the self relies partly on its reciprocal relationships with autobiographical memories, little is known about how memories ground “self-images” in schizophrenia. Twenty-five patients with schizophrenia and 25 controls were asked to give six autobiographical memories related to four self-statements they considered essential for defining their identity. Results showed that patients’ self-images were more passive than those of controls. Autobiographical memories underlying (...) self-images were less thematically linked to these self-images in patients. We also found evidence of a weakened sense of self and a deficient organization of autobiographical memories grounding the self in schizophrenia. These abnormalities may account for the poor cohesiveness of the self in schizophrenia. (shrink)

Psychiatric treatment and diagnosis rests upon a richer conception of normativity than, for example, cognitive neuropsychology. This paper explores the role that considerations of rationality can play in defining this richer conception of normativity. It distinguishes two types of rationality and considers how each type can break down in different ways in delusional psychiatric disorders.

Schizophrenia is a severe mental illness affecting sense of identity. Autobiographical memory deficits observed in schizophrenia could contribute to this altered sense of identity. The ability to give a meaning to personally significant events is also critical for identity construction and self-coherence. Twenty-four patients with schizophrenia and 24 control participants were asked to recall five self-defining memories. We assessed meaning making in participants’ narratives and afterwards asked them explicitly to give a meaning to their memories . We found that both (...) spontaneous and cued meaning making were impaired in patients with schizophrenia. This impairment was correlated with executive dysfunctions and level of negative symptoms. Our results suggest that patients’ difficulties in drawing lessons about past experiences could contribute to explain the lack of coherence observed in their life trajectories and their impaired social adjustment abilities. Implications for psychotherapy are also discussed. (shrink)

Diverse evidence from genomics, epidemiology, neurophysiology, psychology, and evolutionary biology converges on simple general mechanisms, based on negative secondary effects of strong selection, for how mental disorders such as psychosis have evolved and how they are sustained. (Published Online November 9 2006).

(2013). Does consciousness entail subjectivity? The puzzle of thought insertion. Philosophical Psychology: Vol. 26, No. 2, pp. 291-314. doi: 10.1080/09515089.2011.625117.

According to what we will call subjectivity theories of consciousness, there is a constitutive connection between phenomenal consciousness and subjectivity: there is something it is like for a subject to have mental state M only if M is characterized by a certain mine-ness or for-me-ness. Such theories appear to face certain psychopathological counterexamples: patients appear to report conscious experiences that lack this subjective element. A subsidiary goal of this chapter is to articulate with greater precision both subjectivity theories and the (...) psychopathological challenge they face. The chapter’s central goal is to present two new approaches to defending subjectivity theories in the face of this challenge. What distinguishes these two approaches is that they go to great lengths to interpret patients’ reports at face value – greater length, at any rate, than more widespread approaches in the extant literature. (shrink)

In the USA and England and Wales, involuntary treatment for mental illness is subject to the constraint that it must be necessary for the health or safety of the patient, if he poses no danger to others. I will argue against this necessary condition of administering treatment and propose that the category of individuals eligible for involuntary treatment should be extended. I begin by focusing on the common disorder of schizophrenia and proceed to demonstrate that it can be a considerable (...) harm to a person's life without causing the person to be a danger to himself. I illuminate this claim by constructing a thought experiment concerning a person who slips on a banana peel and falls into a malfunctioning version of Robert Nozick's experience machine. I propose that the reasons why we should remove the person from the machine are the same reasons why we should administer involuntary treatment to individuals with schizophrenia. I rebut three objections to the analogy and conclude that if we believe that we have a duty to provide treatment for reasons relating to a person's wellbeing, it follows that we should reject the health or safety requirement and instead broaden the category of individuals who are eligible for involuntary treatment. (shrink)

Questionnaires on perceptual distortions, symptoms of schizophrenia, and out-of-body experiences (OBEs) were completed by 71 volunteers with a history of schizophrenia and 40 control subjects (patients in a hospital accident ward). Significantly more of the schizophrenics (42%) than of the control group (13%) answered "yes" to a question about OBEs. However, a follow-up questionnaire showed that only 14% of schizophrenics (i.e., the same as the control group) had had "typical" OBEs, in which a change of viewpoint was reported. Those reporting (...) typical OBEs did not report more perceptual distortions or symptoms of schizophrenia than did those reporting no OBEs, although those reporting other atypical experiences did. On this basis there is no evidence to consider the typical OBE as pathological or as symptomatic of schizophrenia. (shrink)