Impaired perception of a partner's synchronizing behavior reduces positive attitude toward humanoid robot in schizophrenia patients.

As interpersonal synchrony plays a key role in building rapport, the perception of another agent's synchronizing behavior could be an important feature to assess, especially with patients with social deficits such as in schizophrenia. Twenty-four schizophrenia patients and twenty-four matched healthy controls performed jointly fitness movements with another agent embodied by a humanoid robot which was programmed to either synchronize with the participants or move at a fixed frequency with them. Self-report of participants' perception of the robot's synchronizing behavior was collected after each interaction. Results indicated that patients were impaired in their ability to accurately perceive the robot's synchronizing behavior. Patients' subjective perception of the robot's synchronizing behavior was associated with positive attitude toward it, suggesting that the belief to be synchronized with others could have similar impact on affiliation than real interpersonal synchrony. It leads to new perspectives for understanding social deficits in people with severe mental illness.

Preliminary evidence that fatigue contributes to anhedonia in stable individuals diagnosed with schizophrenia.

Objectives: Anhedonia and fatigue are trans-diagnostic symptoms commonly observed in schizophrenia. Anhedonia is a core negative symptom with a strong relationship with depression and is associated with diminished global functioning. Similarly, fatigue is also associated to depression and research across psychiatric illnesses indicate that fatigue may persist even when primary symptoms are treated. Although fatigue is common in people diagnosed with schizophrenia, it is under studied within this population. The objective of this exploratory study was to investigate the association of fatigue and anhedonia by controlling for depression in a sample of individuals diagnosed with schizophrenia. Method: Fifty-one stable individuals diagnosed with schizophrenia from the University Department of Adult Psychiatry in Montpellier took part in this study. Participants completed questionnaires on fatigue impact and depression, and were assessed for symptom severity. Following data collection, statistical analyses were conducted in order to explore associations between clinical variables and fatigue impact. Based on the results obtained, a hierarchical linear regression was conducted in order to investigate whether fatigue impact contributed to the variance of negative symptoms. Results: The hierarchical linear regression indicated that when controlling for depression, fatigue impact contributes to ~20% of the variance of anhedonia. Together the social impact of fatigue and depression contribute to 24% of the variation of anhedonia. Conclusion: To the best of our knowledge, this exploratory study is the first to investigate and show that fatigue impact may contribute to anhedonia. We recommend further research to investigate fatigue, its impact on symptomatology, and better categorization of negative symptoms in hopes of developing targeted fatigue treatment interventions.

Validation of the French Clinical Assessment Interview for Negative Symptoms in a Sample of Stable French Individuals With Schizophrenia.

Objectives: The Clinical Assessment Interview for Negative Symptoms (CAINS) is an interview-based instrument evaluating the existence and severity of negative symptoms in people diagnosed with schizophrenia or schizoaffective disorder. The aim of this study is to translate and validate a French version of the CAINS in a French sample of outpatients diagnosed with schizophrenia or schizoaffective disorder. Methods: In this study, we included 84 outpatients with a diagnosis of schizophrenia from the University Department of Adult Psychiatry in Montpellier, France. All participants were assessed for the severity of negative symptoms as well as level of depression. Psychometric properties of the French CAINS were investigated including its factor structure, internal consistency, and interrater and test-retest reliabilities. We also determined the discriminant and convergent validity. Results: Exploratory factor analysis and parallel analysis reproduced the two-factor model, and explained 43.55% of the total score variation with good internal consistency (Cronbach α of 0.87). Both interrater and test-retest reliabilities were high for the CAINS and its subscales (intraclass correlation coefficient range, 0.89-0.99). The standard errors of measurement and minimal detectable change were also investigated. Convergent validity of the CAINS was underpinned by correlations obtained with various measures of negative symptoms. Adequate discriminant validity was established by showing that the CAINS did not correlate with positive symptoms. Conclusion: Overall, our results obtained were similar to those found in the original study of the CAINS. Structural analyses also replicated the two-factor model of the CAINS. Our results indicate that the French CAINS has robust psychometric properties and is a valid tool for evaluating negative symptoms in French-speaking individuals diagnosed with schizophrenia.

Getting a tool gives wings even in schizophrenia: underestimation of tool-related effort in a motor imagery task.

Humans frequently use tools to reduce action-related efforts. Interestingly, several studies have demonstrated that individuals had tool-related biases in terms of perceived effort reduction during motor imagery tasks, despite the lack of evidence of real benefits. Reduced effort allocation has been repeatedly found in schizophrenia, but it remains unknown how schizophrenia patients perceive tool-related benefits regarding effort. Twenty-four schizophrenia patients and twenty-four nonclinical participants were instructed to move the same quantities of objects with their hands or with a tool in both real and imagined situations. Imagined and real movement durations were recorded. Similarly to nonclinical participants, patients overestimated tool-related benefits and underestimated tool-related effort in terms of time when they mentally simulated a task requiring the use of a tool. No association between movement durations and psychotic symptoms was found. Our results open new perspectives on the issue of effort in schizophrenia.

Too much or too little? Exploring effort perception in schizophrenia within the framework of motivational intensity theory.

Introduction: To explain motivational difficulties in schizophrenia (SZ), attention has focused on the reward system and effort-based decision-making deficits. However, according to motivational intensity theory (MIT), effort is not directly determined by reward but by task difficulty. Moreover, no studies have examined the effort perception in the SZ. Therefore, this cross-sectional study compared effort perception in SZ group with healthy controls. Method: Task difficulty was manipulated by increasing the distance covered (from 8 to 48 metres). Walking speed, perceptions of difficulty and effort were assessed for all difficulty levels. Clinical and bodyweight variables were recorded. Results: As postulated by MIT, perceived effort and difficulty increased with task difficulty in both groups. Perceived effort and difficulty were higher in the SZ group. Perceptions of effort were positively correlated with BMI in SZ, but not with clinical variables. Importantly, although SZ patients perceived the task as more effortful, walking speed was similar between groups. Conclusions: Taken together, these results suggested that individuals with SZ perceived more strongly the effort and the difficulty of the task but could mobilise more effort to complete it. This observation may explain in part the decrease in engaging in physical demanding activities in daily life in SZ.