Computational mechanisms of belief updating in relation to psychotic-like experiences.

Introduction: Psychotic-like experiences (PLEs) may occur due to changes in weighting prior beliefs and new evidence in the belief updating process. It is still unclear whether the acquisition or integration of stable beliefs is altered, and whether such alteration depends on the level of environmental and belief precision, which reflects the associated uncertainty. This motivated us to investigate uncertainty-related dynamics of belief updating in relation to PLEs using an online study design. Methods: We selected a sample (n = 300) of participants who performed a belief updating task with sudden change points and provided self-report questionnaires for PLEs. The task required participants to observe bags dropping from a hidden helicopter, infer its position, and dynamically update their belief about the helicopter's position. Participants could optimize performance by adjusting learning rates according to inferred belief uncertainty (inverse prior precision) and the probability of environmental change points. We used a normative learning model to examine the relationship between adherence to specific model parameters and PLEs. Results: PLEs were linked to lower accuracy in tracking the outcome (helicopter location) (ß = 0.26 ± 0.11, p = 0.018) and to a smaller increase of belief precision across observations after a change point (ß = -0.003 ± 0.0007, p < 0.001). PLEs were related to slower belief updating when participants encountered large prediction errors (ß = -0.03 ± 0.009, p = 0.001). Computational modeling suggested that PLEs were associated with reduced overall belief updating in response to prediction errors (ßPE = -1.00 ± 0.45, p = 0.028) and reduced modulation of updating at inferred environmental change points (ßCPP = -0.84 ± 0.38, p = 0.023). Discussion: We conclude that PLEs are associated with altered dynamics of belief updating. These findings support the idea that the process of balancing prior belief and new evidence, as a function of environmental uncertainty, is altered in PLEs, which may contribute to the development of delusions. Specifically, slower learning after large prediction errors in people with high PLEs may result in rigid beliefs. Disregarding environmental change points may limit the flexibility to establish new beliefs in the face of contradictory evidence. The present study fosters a deeper understanding of inferential belief updating mechanisms underlying PLEs.

Aeromedical retrievals as a measure of potentially preventable hospitalisations and cost comparison with provision of GP-led primary health care in a remote Aboriginal community.

INTRODUCTION: Kowanyama is a very remote Aboriginal community on the Cape York Peninsula of Far North Queensland, Australia. It is among the five most disadvantaged communities in Australia, with a very high burden of disease. It has access to 2.5 days each week of fly-in, fly-out, GP-led primary health care for a population of 1200. All patients requiring higher level care undergo aeromedical retrieval to a bigger centre. A retrospective clinical audit of charts was undertaken assessing aeromedical retrievals from Kowanyama for the year 2019 to assess whether GP access might correlate with retrievals or hospital admissions for potentially preventable conditions and whether it could be cost-effective and improve outcomes to provide the benchmarked staffing of GPs. METHODS: Using a tool made by the authors for this audit, the management and reason for evacuation were assessed against Queensland Health's Primary Clinical Care Manual guidelines, whether the presence of a rural generalist GP would have prevented the need for retrieval, and assessed against accepted Australian (and Canadian) criteria for potentially preventable hospital admissions. Each retrieval was then assessed as 'preventable' or 'not preventable'. The cost of providing benchmark levels of GPs in community was compared with the cost of potentially preventable retrievals. RESULTS: In 2019, there were 89 retrievals of 73 patients. Thirty-nine percent (35) of all retrievals occurred when a doctor was on site. Of preventable retrievals, 33% (18) occurred with a doctor on site and 67% (36) occurred with no doctor on site. All retrievals with a doctor on site resulted in an admission. All immediate discharges (10% (9)) or deaths (1% (1)) were for retrievals without a doctor on site. Sixty-one percent (54) of all retrievals were potentially preventable, with the two most common conditions being pneumonia - non vaccine preventable (18% (9)) and bacterial/unspecified (14% (7)). Thirty-two percent (20) of patients accounted for 52% (46) of retrievals and of these 63% (29) were potentially preventable (compared to 61% overall). For preventable condition retrievals, the mean number of visits to the clinic compared to non-preventable condition retrievals was higher for registered nurse or Aboriginal Health Worker visits (1.24 v 0.93) and lower for doctor visits (0.22 v 0.37). The conservatively calculated costs of retrievals matched the maximum cost of providing benchmark numbers (2.6 full-time equivalents) of rural generalist doctors in a rotating model for the audited community. CONCLUSION: Greater access to GP-led primary health care may lead to fewer retrievals/hospital admissions for potentially preventable conditions. It is likely that some preventable condition retrievals might be avoided if full coverage with benchmarked numbers of rural generalist GPs in a GP-led primary health team was provided in remote communities. This may be cost-effective and improve patient outcomes, and should be further explored.

Aeromedical retrievals as a measure of potentially preventable hospitalisations and cost comparison with provision of GP-led primary health care in a remote community.

INTRODUCTION: Kowanyama is a very remote Aboriginal community. It is ranked amongst the top five most disadvantaged communities in Australia and has a very high burden of disease. Currently, the community has access to GP-led Primary Health Care (PHC) 2.5 days a week for a population of 1200 people. This audit aims to assess whether GP access correlates with retrievals and/or hospital admissions for potentially preventable conditions and whether it is cost effective and improves outcomes to provide the benchmarked staffing of GPs. METHODS: A clinical audit was undertaken of aeromedical retrievals for the year 2019 to assess whether access to a rural GP would have prevented the need for retrieval and whether the condition for retrieval was 'preventable' or 'not preventable'. A cost-analysis was undertaken to compare the cost of providing accepted benchmark levels of GPs in community with the cost of potentially preventable retrievals. RESULTS: There were 89 retrievals of 73 patients in 2019. 61% of all retrievals were potentially preventable. Most (67%) of the preventable retrievals occurred with no doctor on site. For preventable condition retrievals, the mean number of visits to the clinic compared with non-preventable condition retrievals was higher for registered nurse or health worker visits (1.24 vs 0.93) and lower for GP visits (0.22 vs 0.37). The conservatively calculated costs of retrievals for 2019 matched the maximum cost of providing benchmark numbers (2.6 FTE) of rural generalist (RG) GPs in a rotating model for the audited community. CONCLUSION: Greater access to GP-led PHC appears to lead to fewer retrievals and hospital admissions for potentially preventable conditions. It is likely that some preventable condition retrievals would be avoided if a GP was always on site. Providing benchmarked numbers of RG GPs in a rotating model in remote communities is cost-effective and would improve patient outcomes.

A meta aggregation of qualitative research on retention of general practitioners in remote Canada and Australia.

OBJECTIVE: Our aim was to systematically review qualitative evidence regarding the experiences and perceptions of general practitioners and what factors influence their retention in remote areas of Canada and Australia. The objectives were to identify gaps and inform policy to improve retention of remote general practitioners, which should in turn improve the health of our marginalised remote communities. DESIGN: Meta-aggregation of qualitative studies. SETTING: Remote general practice in Canada and Australia. PARTICIPANTS: General practitioners and general practice registrars who had worked in a remote area for a minimum of one year and/or were intending to stay remote long term in their current placement. RESULTS: Twenty-four studies were included in the final analysis. A total of 811 participants made up the sample with a length of retention ranging from 2 to 40 years. Six synthesised findings were identified from a total of 401 findings; these were around peer and professional support, organisational support, uniqueness of remote lifestyle and work, burnout and time off, personal family issues and cultural and gender issues. CONCLUSIONS: Long term retention of doctors in remote areas of Australia and Canada is influenced by a range of negative and positive perceptions, and experiences with key factors being professional, organisational, or personal. All six factors span a spectrum of policy domains and service responsibilities and therefore a central coordinating body could be well placed to implement a multifactorial retention strategy.

Acute stress alters probabilistic reversal learning in healthy male adults.

Behavioural adaptation is a fundamental cognitive ability, ensuring survival by allowing for flexible adjustment to changing environments. In laboratory settings, behavioural adaptation can be measured with reversal learning paradigms requiring agents to adjust reward learning to stimulus-action-outcome contingency changes. Stress is found to alter flexibility of reward learning, but effect directionality is mixed across studies. Here, we used model-based functional MRI (fMRI) in a within-subjects design to investigate the effect of acute psychosocial stress on flexible behavioural adaptation. Healthy male volunteers (n = 28) did a reversal learning task during fMRI in two sessions, once after the Trier Social Stress Test (TSST), a validated psychosocial stress induction method, and once after a control condition. Stress effects on choice behaviour were investigated using multilevel generalized linear models and computational models describing different learning processes that potentially generated the data. Computational models were fitted using a hierarchical Bayesian approach, and model-derived reward prediction errors (RPE) were used as fMRI regressors. We found that acute psychosocial stress slightly increased correct response rates. Model comparison revealed that double-update learning with altered choice temperature under stress best explained the observed behaviour. In the brain, model-derived RPEs were correlated with BOLD signals in striatum and ventromedial prefrontal cortex (vmPFC). Striatal RPE signals for win trials were stronger during stress compared with the control condition. Our study suggests that acute psychosocial stress could enhance reversal learning and RPE brain responses in healthy male participants and provides a starting point to explore these effects further in a more diverse population.

Models of Dynamic Belief Updating in Psychosis-A Review Across Different Computational Approaches.

To understand the dysfunctional mechanisms underlying maladaptive reasoning of psychosis, computational models of decision making have widely been applied over the past decade. Thereby, a particular focus has been on the degree to which beliefs are updated based on new evidence, expressed by the learning rate in computational models. Higher order beliefs about the stability of the environment can determine the attribution of meaningfulness to events that deviate from existing beliefs by interpreting these either as noise or as true systematic changes (volatility). Both, the inappropriate downplaying of important changes as noise (belief update too low) as well as the overly flexible adaptation to random events (belief update too high) were theoretically and empirically linked to symptoms of psychosis. Whereas models with fixed learning rates fail to adjust learning in reaction to dynamic changes, increasingly complex learning models have been adopted in samples with clinical and subclinical psychosis lately. These ranged from advanced reinforcement learning models, over fully Bayesian belief updating models to approximations of fully Bayesian models with hierarchical learning or change point detection algorithms. It remains difficult to draw comparisons across findings of learning alterations in psychosis modeled by different approaches e.g., the Hierarchical Gaussian Filter and change point detection. Therefore, this review aims to summarize and compare computational definitions and findings of dynamic belief updating without perceptual ambiguity in (sub)clinical psychosis across these different mathematical approaches. There was strong heterogeneity in tasks and samples. Overall, individuals with schizophrenia and delusion-proneness showed lower behavioral performance linked to failed differentiation between uninformative noise and environmental change. This was indicated by increased belief updating and an overestimation of volatility, which was associated with cognitive deficits. Correlational evidence for computational mechanisms and positive symptoms is still sparse and might diverge from the group finding of instable beliefs. Based on the reviewed studies, we highlight some aspects to be considered to advance the field with regard to task design, modeling approach, and inclusion of participants across the psychosis spectrum. Taken together, our review shows that computational psychiatry offers powerful tools to advance our mechanistic insights into the cognitive anatomy of psychotic experiences.

Neuromelanin-Sensitive Magnetic Resonance Imaging in Schizophrenia: A Meta-Analysis of Case-Control Studies.

Background: Psychiatry is in urgent need of reliable biomarkers. Novel neuromelanin-sensitive magnetic resonance imaging (NM-MRI) sequences provide a time-efficient and non-invasive way to investigate the human brain in-vivo. This gives insight into the metabolites of dopaminergic signaling and may provide further evidence for potential dopaminergic alterations in patients with schizophrenia (SCZ). The present systematic review provides a meta-analysis of case-control studies using neuromelanin-sensitive sequences in SCZ vs. healthy controls (HC). Methods: According to predefined search terms and inclusion criteria studies were extracted on PubMed. Meta-analyses with a fixed and random-effects model with inverse variance method, DerSimonian-Laird estimator for τ2, and Cohen's d were calculated. Bias was assessed using funnel plots. The primary study outcome was contrast-to-noise ratio (CNR) in the substantia nigra compared between HC and SCZ. Results: The total sample of k = 6 studies included n = 183 cases and n = 162 controls. Across all studies we found a significant elevation of CNR in the substantia nigra (d = 0.42 [0.187; 0.655], z = 3.521, p < 0.001) in cases compared to controls. We found no significant difference in the control region of locus coeruleus (d = -0.07 [-0.446; 0.302], z = -0.192, p = 0.847), with CNR for the latter only reported in k = 3 studies. Conclusion: CNR in the substantia nigra were significantly elevated in cases compared to controls. Our results support neuromelanin as a candidate biomarker for dopaminergic dysfunction in schizophrenia. Further studies need to assess this candidate marker in large, longitudinal cohorts and address potential effects of disease state, medication and correlations with symptoms.

Retention of General Practitioners in remote areas of Canada and Australia: A meta-aggregation of qualitative research.

OBJECTIVE: Our aim was to systematically review qualitative evidence regarding the experiences and perceptions of General Practitioners and the factors influencing retention in remote areas of Canada and Australia. The objectives were to identify gaps and inform policy to improve retention of remote doctors, which should in turn reduce health inequalities for remote communities. DESIGN: Meta-aggregation of qualitative studies of General Practitioners and general practice registrars who had worked in a remote area of Australia or Canada for a minimum of 1 year and/or were intending to stay remote long term in their current placement. RESULTS: Six synthesised findings were identified: peer and professional support, organisational support, uniqueness of remote lifestyle and work, burnout and time off, personal family issues and cultural and gender issues. CONCLUSIONS: Long-term retention of doctors in remote areas of Australia and Canada is influenced by a range of negative and positive perceptions, and experiences with key factors being professional, organisational and personal. All 6 synthesised findings span a spectrum of policy domains and service responsibilities, and therefore, a central coordinating body could be well placed to implement a multifactorial retention strategy.

Associations between hypomania proneness and attentional bias to happy, but not angry or fearful, faces in emerging adults.

Mania, the core feature of bipolar disorder, is associated with heightened and positive emotion responding. Yet, little is known about the underlying cognitive processes that may contribute to heightened positive emotionality observed. Additionally, while previous research has investigated positive emotion biases in non-clinical samples, few if any, account for subthreshold clinical symptoms or traits, which have reliably assessed psychopathological risk. The present study compared continuous scores on a widely used self-report measure of hypomania proneness (HPS-48) with a dot-probe task to investigate attentional biases for happy, angry, fearful, and neutral faces among 66 college student participants. Results suggested that hypomania proneness was positively associated with attentional bias towards happy, but not angry or fearful faces. Results remained robust when controlling for positive affect and did not appear to be affected by negative affect or current symptoms of depression, anxiety, and stress. Findings provide insight into potential behavioural markers that co-occur with heightened positive emotional responding and hypomania in emerging adults.

"Wonderful! We've just missed the bus." - Parental use of irony and children's irony comprehension.

Irony is one of the linguistic means in which intended and expressed meaning diverge. It serves social-communicative functions, requires the understanding of the speaker's mental state and its comprehension takes place at an advanced stage of language acquisition. In the present study, we investigated 8-year old's irony comprehension and social skills and asked their parents about their preferred use of irony towards their children. We then compared children with the highest scores in irony comprehension test with those with lower scores. The full sample included 46 families from Poland. Results show positive associations between children's levels of irony comprehension and levels of mothers irony use. No such relations were found for fathers. No differences were found in ToM scores between proficient and non-proficient irony comprehenders. Our findings provide a base for future studies to study the use of irony in child-parent talk in more diverse culturally and linguistically diverse populations.

Retraining automatic action tendencies in obesity.

Eating behavior in obesity resembles addictive disorders in that individuals have difficulties inhibiting problematic eating behavior. They show an approach bias - a tendency to approach rather than avoid problematic stimuli. Here, we investigate the existence of such a bias towards healthy and unhealthy food in individuals with normal-weight and obesity. We further aimed to assess whether it is possible to retrain a bias, and whether training would differentially affect our two weight groups. 60 participants completed a training form of the Approach-Avoidance Task (AAT) on three consecutive days. Using a joystick, they were implicitly trained to approach healthy and to avoid unhealthy food pictures. Prior to training, individuals with obesity showed stronger approach tendencies towards food pictures than normal-weight individuals. In individuals with obesity, approach tendencies could be diminished for unhealthy food through one training session and stayed weakened for the following days. In normal-weight participants, approach tendencies towards healthy food could be enhanced over the days of training. Findings indicate that automatic approach tendencies can be changed through training, thus offering possibilities for obesity treatment. Future studies should expand on these findings, for example by including pictures of neutral objects or a no-training control condition.

My journey into Aboriginal and Torres Strait Islander health.

Although all Australian healthcare providers are acutely aware of the health outcomes for Aboriginal and Torres Strait Islander peoples, many general practitioners may feel unprepared to take on the challenge of working in an Aboriginal medical service or in a remote Indigenous community. To highlight the immense rewards, without minimising the challenges, AFP invited Dr Lara Wieland, a GP with longstanding experience in the front-line of providing primary care for Aboriginal peoples, to share her thoughts.