Agency In Schizophrenia Research Articles

Altered awareness of action in schizophrenia: a specific deficit in predicting action consequences

Patients suffering from schizophrenia may report unusual experiences of their own actions. They may either feel that external forces are controlling their actions or even their thoughts, or they may feel in control of events that in fact are not caused by their actions. Most theories link these disturbances in the sense of agency to deficits in motor prediction, resulting in a mismatch between predicted and actual sensory feedback at a central comparator mechanism. Such theories therefore can account for situations in which the sense of agency is reduced. However, other experiments as well as clinical observations show an enhanced rather than reduced sense of agency in schizophrenic patients. Here, we distinguish between a predictive and a retrospective mechanism where both contribute to the experience of agency, and show that schizophrenia is associated with a specific impairment to the predictive component. We measured subjective time estimates of self-initiated voluntary action (a key press) that were followed by a sensory effect (a tone). When the voluntary actions had a high probability of causing tones, healthy volunteers showed a predictive shift of the perceptual estimate of the action towards the tone, even on occasional trials where the tone was omitted. No such shift occurred in the absence of the tone on blocks when tones were less frequent. The predictive component of action awareness was calculated as the difference between time estimates on 'action only' trials from blocks with lower and higher tone probabilities. Schizophrenic patients lacked this predictive component of action awareness, showing a shift on 'action only' trials, regardless of the probability of the tone. Importantly, the schizophrenic deficit in predicting the relation between action and effect was strongly correlated with severity of positive psychotic symptoms, specifically delusions and hallucinations. Furthermore, the patients showed an exaggerated retrospective binding between action and tone, shifting the perceived time of action whenever the tone occurred, relative to when it did not occur. Our quantitative, implicit measures show how basic sensory and motor experience may be altered in acute psychosis. The enhanced sense of agency in schizophrenia reflects reliance on retrospection, rather than prediction, to associate actions with external events. The failure to predict the effects of one's own actions may underlie the blurring and confusion in the relationship between the self and the world that characterizes acute psychosis.

P03-98 - A virtual reality based approach to investigate self monitoring and self agency in schizophrenia

ObjectiveIt has been shown that a disorder of self-monitoring and/or self agency may underlie positive symptoms in schizophrenia, such as hallucinations and delusions of control. The objective of our study was to explore the deficit of these constructs in a sample of schizophrenic subjects by means of low-cost virtual reality.Methods15 schizophrenic subjects and 10 age matched control subjects were tested in two different sessions of a Microsoft Xbox videogame (Dungeons & Dragons: Heroes), in which two players had to cooperate by fighting against various enemies in a virtual space. In each session an avatar was assigned to the test subject: in the first session the test subject's avatar was distinguished by a different coloured circle from the tester's one. In the second session the test subject's avatar was identical to the tester's one. Before playing the game, the schizophrenic test subjects and controls were evaluated on a neuropsychological battery including visuo spatial and executive abilities. Clinical characteristics of the schizophrenic subjects were also assessed.ResultsWhile in the first session patients and normal controls performed similarly, in the second session schizophrenic subjects confused their own avatar more often with the tester's one compared to normal controls (ANOVA Sig.,035). A regression analysis identified visuospatial abilities and set shifting as best predictors of performance in the videogame, while there was no correlation between the performance in the videogame and the clinical variables.ConclusionsLow-cost virtual reality can be used to explore deficits of self monitoring/self agency in schizophrenia.

Misattributions of agency in schizophrenia are based on imprecise predictions about the sensory consequences of one's actions

The experience of being the initiator of one's own actions seems to be infallible at first glance. Misattributions of agency of one's actions in certain neurological or psychiatric patients reveal, however, that the central mechanisms underlying this experience can go astray. In particular, delusions of influence in schizophrenia might result from deficits in an inferential mechanism that allows distinguishing whether or not a sensory event has been self-produced. This distinction is made by comparing the actual sensory information with the consequences of one's action as predicted on the basis of internal action-related signals such as efference copies. If this internal prediction matches the actual sensory event, an action is registered as self-caused; in case of a mismatch, the difference is interpreted as externally produced. We tested the hypothesis that delusions of influence are based on deficits in this comparator mechanism. In particular, we tested whether patients' impairments in action attribution tasks are caused by imprecise predictions about the sensory consequences of self-action. Schizophrenia patients and matched controls performed pointing movements in a virtual-reality setup in which the visual consequences of movements could be rotated with respect to the actual movement. Experiment 1 revealed higher thresholds for detecting experimental feedback rotations in the patient group. The size of these thresholds correlated positively with patients' delusions of influence. Experiment 2 required subjects to estimate their direction of pointing visually in the presence of constantly rotated visual feedback. When compared to controls, patients' estimates were significantly better adapted to the feedback rotation and exhibited an increased variability. In interleaved trials without visual feedback, i.e. when pointing estimates relied solely on internal action-related signals, this variability was likewise increased and correlated with both delusions of influence and the size of patients' detection thresholds as assessed in the first experiment. These findings support the notion that delusions of influence are based on imprecise internal predictions about the sensory consequences of one's actions. Moreover, we suggest that such imprecise predictions prompt patients to rely more strongly on (and thus adapt to) external agency cues, in this case vision. Such context-dependent weighted integration of imprecise internal predictions and alternative agency cues might thus reflect the common basis for the various misattributions of agency in schizophrenia patients.

Impaired Agency in Schizophrenia: Family Therapy with a Young Adult Patient

ABSTRACT This article illustrates the value of utilizing brief psychodynamically oriented interventions to examine how problematic family dynamics exacerbate underlying internal deficits in a young adult with schizophrenia. The propensity for enactments to occur in psychodynamic family therapy is also emphasized. A clinical example illustrates the family therapist's capacity to detect and understand the potential for an enactment, to remain differentiated from the family, and to make conscious the family's unconscious defensive behaviors, which allows family members to begin to recognize the ways in which they are caught in loyalty binds that may inhibit the development of a personal sense of agency by the young adult.

Misattribution of agency in schizophrenia: An exploration of historical first-person accounts

This paper provides a concise description and discussion of bottom–up and top–down approaches to misattribution of agency in schizophrenia. It explores if first-person accounts of passivity phenomena can provide support for one of these approaches. The focus is on excerpts in which the writers specifically examine their experiences of external influence. None of the accounts provides arguments that fit easily with only one of the possible approaches, which is in line with current attempts to theoretical integration.

Agentivité : se vivre ou se juger agent ?

Composante du self, l’agentivité se définit par le fait de se vivre auteur de nos propres actions. Dans la schizophrénie, les idées d’influence, l’automatisme mental et les hallucinations acoustico-verbales seraient dus à un défaut d’agentivité. Frith a suggéré que l’agentivité reposait sur le système automatique de contrôle de l’action (modèles internes). Selon lui, une mauvaise prédiction de celle-ci, ne correspondant pas à l’action désirée, pourrait être à l’origine d’un trouble de l’agentivité. Les travaux de l’équipe de Jeannerod sur les jugements d’attribution ont nuancé cette théorie en avançant que l’agentivité impliquait également des processus conscients. Dernièrement, les travaux de l’équipe de Frith ont fait suggérer que ce serait l’atténuation du ressenti sensoriel, spécifique de nos propres actions, qui rendrait leur vécu différent de celles d’autrui. Le traitement du contexte social et des conséquences sensorielles secondaires à l’action serait également impliqué. L’évolution du concept d’agentivité s’explique par les différentes méthodologies employées. Deux éléments, en lien avec l’utilisation expérimentale de jugements d’attribution, sont source d’ambiguïtés: la définition même de l’agentivité et l’absence de réfutation des théories alternatives. Des études, permettant de préciser et d’explorer ces deux points, seraient nécessaires pour une meilleure compréhension de la physiopathologie de la schizophrénie. Experiencing oneself as the author of an action defines the sense of agency, which is a component of the self. A deficit affecting this process is thought to cause the principle symptoms characterizing schizophrenia - e.g. delusions of control and auditive hallucinations would exist because patients do not experience themselves as the author of their own actions. To explore this specific problem of the sense of agency in schizophrenia, Frith et al. collected a serie of experimental data that lead them to propose that the sense of agency relied on the automatic motor system, processes that enable the predictive adjustment of action. An impairment in these processes (called « internal models » in the literature) would lead to the problem of dissociation between our own actions and those performed by others. More specifically, the problem would lay in the comparison between the predicted state and the desired state (figure 1) . Jeannerod et al. from Lyon used attribution judgements that suggested that the sense of agency would not depend uniquely on the motor mechanisms but would also involve conscious processes. Recently, Frith et al. have published new data that integrates both preceding models. According to this theory, the sense of agency would depend on the processes involved in the predictive control of action but at a conscious level : the attenuation of the sensory feedback, specific of our own actions. This attenuation would depend on the accuracy of comparison between the predicted state and the actual state. Moreover, the sense of agency would also imply the management of social frame, which normally gives the means to cope with human interaction. The conception of the sense of agency has greatly evolved over the years, mainly because of the various experimental methods employed. The consequences of this are the various theoretical interpretations given to the characteristics of the sense of agency. They can be explained in two main points : a non-unified definition of the sense of agency and an absence of experimental data testing alternative interpretations. First, protocols using attribution judgements have proven to be useful to gain better understanding of the attribution mechanism in schizophrenia. However, findings obtained with these judgments have often been used to conclude on deficits of the sense of agency in schizophrenia, whereas the sense of agency is only a sub component of these judgements. More work must be conducted in order to show that generalization from judgements to self-agency is possible. Secondly, data have not been collected in order to go against the accepted proposition that the sense of agency (1) implies conscious processes, comes (2) secondary to action execution because based on sensory attenuation and (3) has subjective consequences only. Further studies would be useful to explore these points, so as to improve our understanding of the physiopathologyogy of schizophrenia.

A pre-reflective indicator of an impaired sense of agency in patients with Schizophrenia

In schizophrenia, passivity phenomenon are clinically related to an abnormal sense of agency, which has been experimentally studied through self-recognition tasks. However, Tsakiris et al. (Cognition 96(3):215-231, 2005) have recently shown in healthy controls that the sense of agency is distinct from self-recognition abilities. We propose a simple motor task to obtain an implicit indicator of the working status of the pre-reflective sense of agency in schizophrenia. Collision dynamics gave us the means to further dissociate agency from motor prediction. Twenty-four patients and a group of matched controls used a hand-held object to stop the fall of a pendulum that was released either by the Subject (task S) or by the Experimenter (task E). The objective indicator of the sense of agency was taken as the efficiency difference between tasks S and E, before the availability of afferent information from collision. Qualitative feedback was provided to assess the top-down effect of explicit information. Motor prediction was as accurate in patients as in controls in tasks E and S. Controls were more efficient in S than in E. Patients revealed similar efficiency levels in both tasks. Qualitative feedback helped but did not affect the efficiency difference between tasks. Our results suggest an impairment of a pure efferent-driven sense of agency in schizophrenia, which is (1) distinct from motor prediction and (2) not under voluntary control. The abnormal judgments previously reported in schizophrenia for self-recognition abilities might be the consequence of a low order deficit of a pre-reflective sense of agency.

Beyond the comparator model: A multifactorial two-step account of agency

There is an increasing amount of empirical work investigating the sense of agency, i.e. the registration that we are the initiators of our own actions. Many studies try to relate the sense of agency to an internal feed-forward mechanism, called the “comparator model”. In this paper, we draw a sharp distinction between a non-conceptual level of feeling of agency and a conceptual level of judgement of agency. By analyzing recent empirical studies, we show that the comparator model is not able to explain either. Rather, we argue for a two-step account: a multifactorial weighting process of different agency indicators accounts for the feeling of agency, which is, in a second step, further processed by conceptual modules to form an attribution judgement. This new framework is then applied to disruptions of agency in schizophrenia, for which the comparator model also fails. Two further extensions are discussed: We show that the comparator model can neither be extended to account for the sense of ownership (which also has to be differentiated into a feeling and a judgement of ownership) nor for the sense of agency for thoughts. Our framework, however, is able to provide a unified account for the sense of agency for both actions and thoughts.