Addressing the elephant in the screening room: an item response theory analysis of the Prodromal Questionnaire (PQ-16) for at-risk symptoms of psychosis.

Within the context of patients at-risk of psychosis, where a variety of symptoms are present, identifying the most discriminative symptoms is essential for efficient detection and management. This cross-sectional online study analyzed individuals from the general population in order to better assess their risk of presenting symptoms belonging to the clinical high risk (CHR) for psychosis, called "CHR-related symptoms". The Prodromal Questionnaire-16 (PQ-16) served as a self-report screening tool. Item response theory (IRT) with a graded response model was used to assess the discrimination and difficulty of its criteria. The analysis included 936 participants (mean age: 21.5 years; 28.1% male, 71.9% female). "Déjà vu" stood out for its high discriminative power, while "Voices or whispers" and "Seen things" demonstrated strong precision relatively to the other CHR-related symptoms. Conversely, "Smell or taste" and "Changing face" were associated with the most severe cases relatively to the other CHR-related symptoms. This study identified the most indicative CHR-related symptoms to emphasize their significance in accurately assessing severity and guiding targeted preventative interventions

Network-level mechanisms underlying effects of transcranial direct current stimulation (tDCS) on visuomotor learning

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation approach in which low level currents are administered over the scalp to influence underlying brain function. Prevailing theories of tDCS focus on modulation of excitation-inhibition balance at the local stimulation location. However, network level effects are reported as well, and appear to depend upon differential underlying mechanisms. Here, we evaluated potential network-level effects of tDCS during the Serial Reaction Time Task (SRTT) using convergent EEG- and fMRI-based connectivity approaches. Motor learning manifested as a significant (p \u3c.0001) shift from slow to fast responses and corresponded to a significant increase in beta-coherence (p \u3c.0001) and fMRI connectivity (p \u3c.01) particularly within the visual-motor pathway. Differential patterns of tDCS effect were observed within different parametric task versions, consistent with network models. Overall, these findings demonstrate objective physiological effects of tDCS at the network level that result in effective behavioral modulation when tDCS parameters are matched to network-level requirements of the underlying task

Top-down and bottom-up processes of auditory hallucination: a comparison of clinical and non-clinical sample

International audienceAuditory hallucinations (AH) can be found both in clinical samples (i.e. schizophrenia) and in the general population. To further understand the continuities and discontinues in terms of mechanisms underlying AH, in our study, we sought to better understand the top-down and bottom-up processes behind this phenomenon in both samples. Indeed, Waters et al. (2012) and other recent models, have highlighted the importance of considering the interplay between top-down (e.g., signal detection) and bottom-down (e.g., sensory information) processes. Participants in both samples will be recruited based on the scores on auditory hallucinations (-proneness). All the participants will complete two versions of the auditory Signal Detection Task (aSDT), the Tone Matching Task (TMT), and questionnaires measuring hallucination proneness and creative experiences. For the aSDT, two noises will be used, one with only human-speech frequencies, and the other one without these frequencies. We hypothesize that participants (clinical and non-clinical) with AH (or proneness) will make more false alarms and will have a decision bias on the aSDT only for trials with the noise containing human-speech frequencies. Patients with schizophrenia will have poorer performances in the TMT than the healthy volunteer. The results presented during this meeting will be preliminary and only on the healthy volunteer. This study will help us to better understand the continuities and discontinues in terms of mechanisms underlying AH and their interactions, in both clinical and non-clinical samples

Processes of Auditory Hallucinations (AH) in a non-clinical and clinical sample

International audienceAround 80% of people with schizophrenia experience auditory hallucinations (AH) like hearing voices. However, non-clinical samples also report such experiences, with rates ranging from 5% to 15% (Toh et al., 2022). Hallucination studies in non-clinical samples can bypass clinical limitations (i.e. medication, hospitalization), but processes may differ between clinical and non-clinical samples (Moseley et al., 2022).Disruptions in both top-down and bottom-up processes have been suggested to be implicated in the emergence of AH (e.g., Waters et al., 2012). Reduced sensitivity/accuracy for signal-noise discrimination and increased expectation biases for sensory input are among the altered cognitive functions related to AH (Moseley et al., 2021). Perceptual decision-making in AH has often been studied with the auditory Signal Detection Task (aSDT). However, the choice of noises (i.e. pink or white noise) used is poorly justified. Moreover, fewer studies have explored the association between basic auditory processing and AH (Dondé, 2019) and most of these studies have important limitations (e.g., related to the definition of AH). Therefore, in this study our goal is to measure bottom-up and top-down processes linked to AH. We hypothesized (1) that patients with schizophrenia will have a poorer ability to discriminate pure tones compared to the general population, even more if they have AH, (2) that individuals with AH will do more false alarms and have a more liberal response bias, compared to individuals without AH, and even more in the human-noise condition.We recruited (and still are) individuals with schizophrenia or schizoaffective disorder, with or without AH, and individuals from the general population, with or without proneness to AH (based on the participants’ answers to the Launay and Slade Hallucination Scale). Participants completed a series of questionnaires (i.e. Launay and Slade Hallucination Scale – Extended (modified), Hamilton Program for Schizophrenia Voices Questionnaire (only for patients) and Creative Experience Questionnaire). Moreover, they completed two auditory tasks, in a randomized order, the Tone Matching Task (TMT; Dondé, 2019) and the auditory Signal Detection Task (aSDT; Moseley et al., 2021). The TMT assesses early auditory processes. The aSDT (Moseley et al., 2021) assesses perceptual decision-making. This task used two different noises: human, with human speech frequencies, or non-human, without these frequencies (Laloyaux, et al., 2022). We are still collecting data and aim to have 100 non-clinical participants by March 2024.In our sample of 75 people from the general population, there was no significant difference in TMT scores between individuals with and without proneness to AH (χ²=0.231, p=.631, ε²=.00312). In the human noise condition, there was no significant difference between groups for the number of false alarms (χ²=2.66, p=.103, ε²=.036) or the response bias (χ²=3.03, p=.082, ε²=.0409). In the non-human noise condition, there was a significant difference between groups for the number of false alarms (χ²=4.22, p=.040, ε²=.0571) but not for response bias (χ²=3.54, p=.06, ε²=.0479). However, those with a proneness to AH had more FA on both noises in the aSDT, although there was no interaction between groups and noises (F=0.277, p=.600, η²=.001).Regarding our results in the non-clinical sample, it doesn’t seem that the bottom-up processes we triggered are linked to proneness to AH. However, individuals with a proneness to AH tend to make more false alarms, but depending on the noise condition, this difference is not always significant. Studying the cognitive processes behind AH can improve interventions (Smailes et al., 2015)

49 Symptoms of Psychotic-Like Experiences: Estimating an Overlap Between Psychotic-Like Experiences Measures

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Patients’ awareness of recovery mediates the link between clinical and level of functional remission in schizophrenia to a larger extent in those treated with long-acting antipsychotics

Background: Clinical remission is a step towards functional remission for subjects with schizophrenia. While recovery is both a subjective personal journey and a clinical outcome to be targeted, data on patient self-rated outcomes are scarce. Objectives: (i) To determine the extent to which the association between clinical and functional remission is mediated by the subjective experience of recovery as reported by patients versus their relatives or their psychiatrist and (ii) to assess differences according to treatment, specifically with oral antipsychotics only versus long-acting injectable antipsychotics (LAIs). Design: Clinical observational study. Methods: Community-dwelling participants with schizophrenia enrolled in the EGOFORS cohort ( N  = 198) were included. Clinical symptoms and remission were assessed using the Positive and Negative Syndrome Scale. Functional remission was assessed with the Functional Remission of General Schizophrenia Scale. Awareness of recovery was assessed with one question ‘What percentage of recovery do you think you have now (from 0% – no recovery – to 100% – full recovery)?’, asked of the patient, also of the patient’s close relative, and the psychiatrist. We used mediation analyses, taking into account the type of pharmacological treatment. Results: Remission criteria and perceived remission measures were significantly correlated, both within and between groups ( r  > 0.330). The patient’s awareness of recovery mediated the relationship between clinical remission and level of functional remission, while the level of recovery according to psychiatrists or close relatives did not. The direct effect of clinical remission on the level of functional remission became non-significant when taking into account the mediator (patients’ awareness of recovery) in the group of patients with LAI ( t  = 1.5, p  = 0.150) but not in the group of patients with other treatments ( t  = 3.1, p  = 0.003). Conclusion: Patients with LAIs may be more efficient in reporting their level of functional remission. Higher patient awareness could be an interesting candidate to explain this. However, as the study was cross-sectional, such a proposal should be tested with a more specifically designed protocol, such as a long-term cohort

How are efforts allocated in schizophrenia? A meta-analysis of effort-cost decision-making studies

Importance: Motivational impairments in schizophrenia are by definition associated with poor outcome. It is postulated that the reduction of goal-directed behavior arises from abnormal tradeoffs between rewards and efforts. Objective: To determine whether schizophrenia is associated with impairments in effort-cost decision-making. Data Sources: The PubMed, EMBASE and PsycINFO databases (up to July 2021) were searched for studies that investigated effort-cost decision-making in schizophrenia (search terms included ‘effort’, ‘cost’ and ‘schizophrenia’). Study Selection: Consensual criteria for inclusion were peer-reviewed studies using an effort-cost decision-making behavioral paradigm and comparing subjects with schizophrenia to controls. Data Extraction and Synthesis: PRISMA guidelines were used for abstracting data. Data were extracted independently by two authors and then pooled using random-effects sizes and Bayesian approaches. Effects of moderators were tested with meta-regressions and sub-group analyses. Main Outcome(s) and Measure(s): Performance on effort-cost decision-making tasks requiring an effort-reward trade-off. Results: Nineteen studies involving 757 subjects with schizophrenia and 589 controls were included. Subjects with schizophrenia exhibited significantly reduced willingness to expend effort for rewards compared to controls (ESg(k=19) = 0.43 [0.29:0.57]; P < .0000001; I² = 36.8%, Q-test P = 0.06; BF10 = 3386). The magnitude of the deficit was significantly higher for high reward trials. Subjects with high levels of negative symptoms exhibited reduced willingness to expend effort for rewards compared to subjects with low negative symptoms (ESg(k=5) = 0.47 [0.1:0.84]; P = 0.013). The meta-regressions did not reveal any significant effect of the intensity of negative symptoms and antipsychotic daily dosage on altered effort-cost computation. Sub-group analyses did not reveal any effect of the type of effort (cognitive vs. physical) and paradigm on effort-cost decision-making performance. Conclusions and Relevance: Schizophrenia is reliably associated with deficits in effort allocation as indexed by effort-cost decision-making tasks. Understanding the cognitive and neurobiological mechanisms driving effort allocation impairments may assist in developing novel interventions

49 Symptoms of Psychotic-Like Experiences: Estimating an Overlap Between Psychotic-Like Experiences Measures

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