The relationship between cognitive phenotypes of compulsivity and impulsivity and clinical variables in obsessive-compulsive disorder: A systematic review and Meta-analysis.

BACKGROUND: This systematic review and meta-analysis explored the relationship between cognitive phenotypes of compulsivity and impulsivity and clinical variables in obsessive-compulsive disorder (OCD). METHODS: We searched Pubmed, Scopus, Cochrane Library and PsychINFO databases until February 2023 for studies comparing patients with OCD and healthy controls on cognitive tests of compulsivity and impulsivity. The study followed PRISMA guidelines and was pre-registered on PROSPERO (CRD42021299017). RESULTS: Meta-analyses of 112 studies involving 8313 participants (4289 patients with OCD and 4024 healthy controls) identified significant impairments in compulsivity (g = -0.58, [95%CI -0.68, -0.47]; k = 76) and impulsivity (g = -0.48, [95%CI -0.57, -0.38]; k = 63); no significant difference between impairments. Medication use and comorbid psychiatric disorders were not significantly related to impairments. No associations were revealed with OCD severity, depression/anxiety, or illness duration. CONCLUSION: Cognitive phenotypes of compulsivity and impulsivity in patients with OCD appear to be orthogonal to clinical variables, including severity of OCD symptomatology. Their clinical impact is poorly understood and may require different clinical assessment tools and interventions.

Systematic review and meta-analysis of preoperative interventions to support the maturation of arteriovenous fistulae in patients with advanced kidney disease.

BACKGROUND: There is great potential to improve outcomes of arteriovenous fistulas (AVFs) by focusing more on the preoperative period of AVF creation. We aim to systematically review the evidence on safety and efficacy of various preoperative interventions that have been tried to improve AVF maturation and success rate. METHODS: We searched five databases: PubMed, Embase, CINAHL, Cochrane Library and King's Fund Library. Experimental studies that investigated the effect of various preoperative interventions to improve AVF outcomes among advanced chronic kidney disease (CKD) patients were searched. The effect size for primary outcome was calculated as the weighted mean difference in the final vessel calibre, rate of AVF maturation or primary failure between the intervention and control arm. We also assessed adverse effects and dropout rates. This review was preregistered in the International Prospective Register of Systematic Reviews (CRD42020193257). RESULTS: Eight eligible studies were identified involving three types of intervention: hand exercise (n = 6), cholecalciferol supplementation (n = 1) and pneumatic compression of the arm using a Fist Assist device (n = 1). The overall effect size of hand exercise on distal cephalic vein calibre was 0.24 mm [95% confidence interval (CI) 0.03-0.45] on meta-analysis of hand exercise studies. On restricting analysis to two randomized controlled trials (RCTs) that had independent control groups, the effect size was higher, at 0.29 mm (95% CI 0.11-0.47). Hand exercise was a well-tolerated intervention, especially when confined to the first 4 weeks. DISCUSSION: Hand exercise is the predominant intervention tried in the preoperative period of AVF creation, although there is methodological heterogeneity. Intermittent pneumatic compression using a Fist Assist device is a novel intervention that has shown some promise. Well-designed prospective RCTs are needed on preoperative interventions among advanced CKD patients, aimed at improving AVF outcomes.

Strange face illusions: A systematic review and quality analysis.

BACKGROUND: Strange face illusions describe a range of visual apparitions that occur when an observer gazes at their image reflected in a mirror or at another person's face in a dimly lit room. The illusory effects range from mild alterations in colour, or contrast, to the perception of distorted facial features, or new strange faces.The current review critically evaluates studies investigating strange face illusions, their methodological quality, and existing interpretations. METHOD: Searches conducted using Scopus, PubMed, ScienceDirect and the grey literature until June 2022 identified 21 studies (N = 1,132; healthy participants n = 1,042; clinical participants n = 90) meeting the inclusion criteria (i.e., providing new empirical evidence relating to strange face illusions). The total sample had a mean age of 28.3 years (SD = 10.31) and two thirds (67 %) of participants tested to date are female. Results are reported using the Preferred Reporting Items for Systematic Reviews and meta-Analyses (PRISMA) guidelines. The review was preregistered at the Open Science Framework (OSF: https://osf.io/ek48d). RESULTS: Pooling data across studies, illusory new strange faces are experienced by 58% (95%CI 48 to 68) of nonclinical participants. Study quality as assessed by the Appraisal Tool for Cross-Sectional Studies (AXIS) revealed that 3/21 (14.28%) studies were rated as high, 9/21 (42.86%) as moderate and 9/21 (42.86%) as low quality. Whilst the items relating specifically to reporting quality scored quite highly, those relating to study design and possible biases were lower and more variable. Overall, study quality accounted for 87% of the variance in reporting rates for strange faces, with higher quality being associated with lower illusion rates. The prevalence of illusions was also significantly greater in samples that were older, had higher proportions of female participants and for the interpersonal dyad (IGDT) compared to the mirror gaze paradigm (MGT). The moderating impact of study quality persisted in a multiple meta-regression involving participant age, paradigm type (IGDT vs MGT) and level of feature distortion. Our review point to the importance of reduced light levels, face stimuli and prolonged eye fixation for strange face illusions to emerge. CONCLUSION: Strange face illusions reliably occur in both mirror-gazing and interpersonal gazing dyad paradigms. Further research of higher quality is required to establish the prevalence and particularly, the mechanisms underpinning strange face illusions.

Effects of exercise on obsessive-compulsive disorder symptoms: a systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis assessed the efficacy of exercise in reducing OCD symptoms. METHODS: We searched PubMed, Cochrane Central Register of Controlled Trials, MEDLINE, Scopus and grey literature until March 2022. The study was preregistered at Prospero (CRD42021283931). We included randomised controlled and pre-post trials assessing physical activity as an intervention for OCD. Risk of bias was assessed using the Cochrane ROBINS-I tool and the RoB2 tool. RESULTS: The analysis included 6 trials (N = 92); 2 were RCTS and 4 were pre-post design studies. A random-effects meta-analysis of pre-post data identified a large reduction of OCD symptoms following exercise (g = 1.33 [95%CI 1.06-1.61]; k = 6). Exercise was also associated with significant pre-post reductions in anxiety (g = 0.71 [95%CI 0.37-1.05; k = 4) and depression (g = 0.57 [95%CI 0.26-0.89]; k = 2). Risk of bias was moderate-high in uncontrolled trials on the ROBINS-I and RCTs showed 'some concerns' on the RoB2. CONCLUSION: Exercise was associated with a large pre-post reduction of OCD symptoms; however, few trials were of robust quality and all were at risk of bias. Further well-powered and better quality RCTs are required to assess the role of exercise as an intervention for OCD.KEY POINTSStudies exploring exercise as an adjunct therapy for OCD have small participant numbers, therefore a systematic review and meta-analysis is needed to estimate potential efficacy.Pre-post analysis shows that exercise was associated with a large reduction of OCD symptomsThe current systematic review and meta-analysis points to the potential for exercise to be beneficial for the treatment for OCD symptoms. However, more well-powered and better controlled RCTs are required to fully assess the benefit of exercise for the treatment of OCD symptoms.

Meta-analysis of cognitive behaviour therapy and selective serotonin reuptake inhibitors for the treatment of hypochondriasis: Implications for trial design.

BACKGROUND: Classification of hypochondriasis as an obsessive-compulsive and related disorder in the International Classification of Diseases 11th Revision (ICD-11) has generated new heuristics for treatment of this common, chronic and disabling disorder. Standard treatment involves cognitive behaviour therapy (CBT) or selective serotonin reuptake inhibitors (SSRIs), but no meta-analysis has so far considered hypochondriasis as a structured diagnosis or assessed the role of medication. A clearer understanding of the relative effectiveness of these interventions and identification of clinically relevant factors moderating the treatment response is needed for clinical guideline development. METHODS: The current systematic review and meta-analysis of interventions for hypochondriasis was preregistered on PROSPERO (CRD42020185768) and follows PRISMA guidelines. We searched MEDLINE, PsycINFO, and Cochrane Library databases until July 2021 for randomized controlled trials (RCTs) of interventions for patients diagnosed with hypochondriasis (or historical diagnostic equivalents). We assessed aspects of study quality using: the CONSORT Checklist for evaluation of RCTs, the Cochrane Risk of Bias 2 tool, researcher allegiance and treatment fidelity. The primary outcome was improvement in hypochondriasis symptoms, comparing intervention and control groups at trial endpoint. Moderator variables were assessed using subgroup and meta-regression analyses. RESULTS: Searches identified 13 randomised controlled trials (RCTs) (N = 1405); 12 included CBT (N = 1212) and three included SSRI (N = 193) arms as the experimental intervention. Random effects meta-analysis yielded a moderate-to-large effect size for CBT versus all controls (g = -0.70 [95% CI -0.99 to -0.41], k = 18, I2 = 81.1%). Funnel plot asymmetry indicated possible publication bias and two potentially missing trials, reducing the effect size (g = -0.60 [95% CI -0.88 to -0.32]). Subgroup analysis showed that choice of control significantly moderated effect size, with those in CBT vs. wait-list (g = -1.32 [95% CI -1.75 to -0.90], k = 7, I2 = 0%) being double those of CBT vs. psychological or pharmacological placebo controls (g = -0.58 [95% CI -0.95 to -0.22], k = 7, I2 = 82%). Analysis of studies directly comparing CBT and SSRIs found a numerical, but not statistical advantage for SSRIs (g = 0.21 [95% CI -0.46 to 0.87], k = 2, I2 = 58.34%) and a modest effect size emerged for SSRIs vs. pill placebo (g = -0.29 [95% CI -0.57 to -0.01], k = 3, I2 = 0%). Most studies (11/13) were rated as high on potential researcher allegiance bias in favour of CBT. Meta-regressions revealed that effect sizes were larger in younger participants, and smaller in better quality and more recent RCTs and those with greater CBT fidelity. CONCLUSION: CBT and SSRIs are effective in the acute treatment of hypochondriasis, with some indication that intervention at a younger age produces better outcomes for CBT. In the case of CBT, effect sizes appear to have been significantly inflated by the use of wait list controls, and researcher allegiance bias. We recommend that a definitive, adequately controlled trial, designed with respect to the methodological issues raised in this meta-analysis, is needed to determine the magnitude effects for CBT and SSRIs with confidence and the long-term effect of treatments, to inform mental health service provision for this overlooked patient group.

Repetitive transcranial magnetic stimulation (r-TMS) and selective serotonin reuptake inhibitor-resistance in obsessive-compulsive disorder: A meta-analysis and clinical implications.

INTRODUCTION: Despite promising results from several randomized controlled trials (RCTs) and meta-analyses, the efficacy of r-TMS as a treatment for OCD remains controversial, at least in part owing to inconsistency in the trial methodologies and heterogeneity in the trial outcomes. This meta-analysis attempts to explain some of this heterogeneity by comparing the efficacy of r-TMS in patients with or without resistance to treatment with selective serotonin reuptake inhibitors (SSRI), defined using standardized criteria. METHODS: We conducted a pre-registered (PROSPERO ID: 241381) systematic review and meta-analysis. English language articles reporting blinded RCTs were retrieved from searches using MEDLINE, PsycINFO, and Cochrane Library databases. Studies were subjected to subgroup analysis based on four stages of treatment resistance, defined using an adaptation of published criteria (1 = not treatment resistant, 2 = one SSRI trial failed, 3 = two SSRI trials failed, 4 = two SSRI trials failed plus one or more CBT trial failed). Meta-regression analyses investigated patient and methodological factors (age, duration of OCD, illness severity, stage of treatment-resistance, or researcher allegiance) as possible moderators of effect size. RESULTS: Twenty-five independent comparisons (23 studies) were included. Overall, r-TMS showed a medium-sized reduction of Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores (Hedge's g: -0.47; 95%CI: - 0.67 to -0.27) with moderate heterogeneity (I2 = 39.8%). Assessment of publication bias using Trim and Fill analysis suggested a reduced effect size that remained significant (g: -0.29; 95%CI: -0.51 to -0.07). Subgroup analysis found that those studies including patients non-resistant to SSRI (stage 1) (g: -0.65; 95%CI: -1.05 to -0.25, k = 7) or with low SSRI-resistance (stage 2) (g:-0.47; 95%CI: -0.86 to -0.09, k = 6) produced statistically significant results with low heterogeneity, while studies including more highly resistant patients at stage 3 (g: -0.39; 95%CI: -0.90 to 0.11, k = 4) and stage 4 (g: -0.36; 95%CI: -0.75 to 0.03, k = 8) did not. Intriguingly, the only significant moderator of the effect size found by meta-regression was the severity of baseline depressive symptoms. All trials showed evidence of researcher allegiance in favour of the intervention and therefore caution is required in interpreting the reported effect sizes. CONCLUSION: This meta-analysis shows that r-TMS is an effective treatment for OCD, but largely for those not resistant to SSRI or failing to respond to only one SSRI trial. As a consequence, r-TMS may be best implemented earlier in the care pathway. These findings would have major implications for clinical service development, but further well-powered RCTs, which eliminate bias from researcher allegiance, are needed before definitive conclusions can be drawn.

Cognitive behavioural therapy with exposure and response prevention in the treatment of obsessive-compulsive disorder: A systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: Cognitive behavioural therapy (CBT), incorporating exposure and response prevention (ERP) is widely recognised as the psychological treatment of choice for obsessive-compulsive disorder (OCD). Uncertainty remains however about the magnitude of the effect of CBT with ERP and the impact of moderating factors in patients with OCD. METHOD: This systematic review and meta-analysis assessed randomised-controlled trials of CBT with ERP in patients of all ages with OCD. The study was preregistered in PROSPERO (CRD42019122311). The primary outcome was end-of-trial OCD symptom scores. The moderating effects of patient-related and study-related factors including type of control intervention and risk of bias were examined. Additional exploratory analyses assessed the effects of treatment fidelity and impact of researcher allegiance. RESULTS: Thirty-six studies were included, involving 2020 patients (537 children/adolescents and 1483 adults) with 1005 assigned to CBT with ERP and 1015 to control conditions. When compared against all control conditions, a large pooled effect size (ES) emerged in favour of CBT with ERP (g = 0.74: 95% CI = 0.51 to 0.97 k = 36), which appeared to diminish with increasing age. While CBT with ERP was more effective than psychological placebo (g = 1.13 95% CI 0.71 to 1.55, k = 10), it was no more effective than other active forms of psychological therapy (g = -0.05: 95% CI -0.27 to 0.16, k = 8). Similarly, whereas CBT with ERP was significantly superior when compared to all forms of pharmacological treatment (g = 0.36: 95% CI 0.7 to 0.64, k = 7), the effect became marginal when compared with adequate dosages of pharmacotherapy for OCD (g = 0.32: 95% CI -0.00 to 0.64, k = 6).A minority of studies (k = 8) were deemed to be at low risk of bias. Moreover, three quarters of studies (k = 28) demonstrated suspected researcher allegiance and these studies reported a large ES (g = 0.95: 95% CI 0.69 to 1.2), while those without suspected researcher allegiance (k = 8) indicated that CBT with ERP was not efficacious (g = 0.02: 95% CI -0.29 to 0.33). CONCLUSIONS: A large effect size was found for CBT with ERP in reducing the symptoms of OCD, but depends upon the choice of comparator control. This meta-analysis also highlights concerns about the methodological rigor and reporting of published studies of CBT with ERP in OCD. In particular, efficacy was strongly linked to researcher allegiance and this requires further future investigation.

Cognitive dysfunction in body dysmorphic disorder: new implications for nosological systems and neurobiological models.

Introduction Body dysmorphic disorder (BDD) is a debilitating disorder, characterized by obsessions and compulsions relating specifically to perceived appearance, and which has been newly classified within the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) Obsessive-Compulsive and Related Disorders grouping. Until now, little research has been conducted into the cognitive profile of this disorder. METHODS: Participants with BDD (n=12) and participants without BDD (n=16) were tested using a computerized neurocognitive battery investigating attentional set-shifting (Intra/Extra Dimensional Set Shift Task), decision-making (Cambridge Gamble Task), motor response-inhibition (Stop-Signal Reaction Time Task), and affective processing (Affective Go-No Go Task). The groups were matched for age, IQ, and education. RESULTS: In comparison to controls, patients with BDD showed significantly impaired attentional set-shifting, abnormal decision-making, impaired response inhibition, and greater omission and commission errors on the emotional processing task. CONCLUSION: Despite the modest sample size, our results showed that individuals with BDD performed poorly compared to healthy controls on tests of cognitive flexibility, reward and motor impulsivity, and affective processing. Results from separate studies in OCD patients suggest similar cognitive dysfunction. Therefore, these findings are consistent with the reclassification of BDD alongside OCD. These data also hint at additional areas of decision-making abnormalities that might contribute specifically to the psychopathology of BDD.

The neuropsychology of obsessive-compulsive personality disorder: a new analysis.

BACKGROUND: Obsessive compulsive personality disorder (OCPD) is characterized by perfectionism, need for control, and cognitive rigidity. Currently, little neuropsychological data exist on this condition, though emerging evidence does suggest that disorders marked by compulsivity, including obsessive-compulsive disorder (OCD), are associated with impairment in cognitive flexibility and executive planning on neurocognitive tasks. AIM: The current study investigated the neurocognitive profile in a nonclinical community-based sample of people fulfilling diagnostic criteria for OCPD in the absence of major psychiatric comorbidity. METHOD: Twenty-one nonclinical subjects who fulfilled Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for OCPD were compared with 15 healthy controls on selected clinical and neurocognitive tasks. OCPD was measured using the Compulsive Personality Assessment Scale (CPAS). Participants completed tests from the Cambridge Automated Neuropsychological Test Battery including tests of set shifting (Intra-Extra Dimensional [IED] Set Shifting) executive planning (Stockings of Cambridge [SOC]), and decision making (Cambridge Gamble Task [CGT]). RESULTS: The OCPD group made significantly more IED-ED shift errors and total shift errors, and also showed longer mean initial thinking time on the SOC at moderate levels of difficulty. No differences emerged on the CGT. CONCLUSIONS: Nonclinical cases of OCPD showed significant cognitive inflexibility coupled with executive planning deficits, whereas decision-making remained intact. This profile of impairment overlaps with that of OCD and implies that common neuropsychological changes affect individuals with these disorders.

The use of ketamine as an antidepressant: a systematic review and meta-analysis.

OBJECTIVE: The current meta-analysis examines the effects of ketamine infusion on depressive symptoms over time in major depressive disorder (MDD) and bipolar disorder (BD). METHODS: Following a systematic review of the literature, data were extracted from 21 studies (n = 437 receiving ketamine) and analysed at four post-infusion time points (4 h, 24 h, 7 days and 12-14 days). The moderating effects of several factors were assessed including: repeat/single infusion, diagnosis, open-label/participant-blind infusion, pre-post/placebo-controlled design and the sex of patients. RESULTS: Effect sizes were significantly larger for repeat than single infusion at 4 h, 24 h and 7 days. For single infusion studies, effect sizes were large and significant at 4 h, 24 h and 7 days. The percentage of males was a predictor of antidepressant response at 7 days. Effect sizes for open-label and participant-blind infusions were not significantly different at any time point. CONCLUSIONS: Single ketamine infusions elicit a significant antidepressant effect from 4 h to 7 days; the small number of studies at 12-14 days post infusion failed to reach significance. Results suggest a discrepancy in peak response time depending upon primary diagnosis - 24 h for MDD and 7 days for BD. The majority of published studies have used pre-post comparison; further placebo-controlled studies would help to clarify the effect of ketamine over time.

Increased frequency of involuntary semantic memories or mind-pops in schizophrenia: a diary study.

INTRODUCTION: Hallucinations constitute a prominent symptom of schizophrenia and may take a variety of forms (verbal, visual, musical, or environmental noises). Interesting similarities exist between hallucinations and so-called mind-pops which refer to isolated fragments of one's semantic knowledge (e.g., a word/sentence, visual image, or a song/melody) that come to mind unexpectedly, often without any obvious triggers, and are difficult to control. The aim of the present study was to evaluate whether mind-pops may constitute the raw cognitive material from which hallucinations are constructed by studying the nature and frequency of mind-pops in the everyday life of people with schizophrenia and non-clinical controls. METHODS: Eleven participants with schizophrenia and 14 non-clinical controls kept a diary of their mind-pops for seven days and completed a brief questionnaire every time they had a mind-pop. RESULTS: Schizophrenia participants reported significantly more verbal and image mind-pops than controls and their content was negative more often than in controls. No group differences were obtained in terms of reported triggers or ongoing activities. Data from both groups also supported the priming hypothesis by showing that stimuli encountered in one's environment or thoughts could later re-appear in the form of a mind-pop. CONCLUSIONS: The findings have implications for models of schizophrenia that emphasise the role of intrusive thoughts and memories in the aetiology and development of key psychotic symptoms.

To admit or not to admit? The effect of framing on risk assessment decision making in psychiatrists.

BACKGROUND: The way that information is presented is well known to induce a range of biases in human decision tasks. Little research exists on framing effects in psychiatric decision making, but it is reasonable to assume that psychiatrists are not immune and, if so, there may be implications for the welfare of patients, staff and the general public. AIMS: To investigate whether presentation of risk information in different formats (frequency, percentage and semantic) influences inpatient admission decisions by psychiatrists. METHODS: Six-hundred seventy-eight general adult psychiatrists read a short clinical vignette presenting a case scenario of a patient presenting for inpatient admission. One of four condition questions followed the vignette, incorporating either numerical or percentage probabilities and the semantic labels "high" and "low" risk. In each condition, the actual risk was identical, but the way it was presented varied. The decision to admit the patient or not was recorded and compared across conditions. RESULTS: More individuals chose to admit the patient when risk information was presented in numerical form (X2 = 7.43, p = 0.006) and with the semantic label "high" (X2 = 7.27, p = 0.007). CONCLUSIONS: Presentation of risk information may influence decision making in psychiatrists. This has important implications for mental health clinical practice where clinicians are required to interpret probabilistic information within their daily work.

From mind-pops to hallucinations? A study of involuntary semantic memories in schizophrenia.

Involuntary semantic memories or mind-pops consist of isolated fragments of one's semantic knowledge (e.g., a word or a sentence, proper name, image or a melody) that come to mind unexpectedly, without any deliberate attempt to recall them. They can be experienced as alien and uncontrollable, and may share some phenomenological similarities with hallucinations. The aim of the present study was to investigate the nature and frequency of mind-pops in people with schizophrenia (N=37), as well as clinically depressed (N=31) and non-clinical controls (N=31). Results showed that schizophrenia patients reported experiencing mind-pops more frequently than both depressed and non-clinical controls. Schizophrenia patients also reported a wider range of different types of mind-pops than non-clinical controls. The depressed group did not differ from non-clinical controls in the frequency and range of mind-pops, indicating that mind-pops are not characteristic of clinical populations in general, but may be particularly prevalent in patients with schizophrenia. The possible implications of this finding to current models of auditory verbal hallucinations are discussed and the need for future research in this area is emphasized.

Is Ginkgo biloba a cognitive enhancer in healthy individuals? A meta-analysis.

OBJECTIVE: We conducted a meta-analysis to examine whether Ginkgo biloba (G. biloba) enhances cognitive function in healthy individuals. METHODS: Scopus, Medline, Google Scholar databases and recent qualitative reviews were searched for studies examining the effects of G. biloba on cognitive function in healthy individuals. We identified randomised controlled trials containing data on memory (K = 13), executive function (K = 7) and attention (K = 8) from which effect sizes could be derived. The analyses provided measures of memory, executive function and attention in 1132, 534 and 910 participants, respectively. RESULTS: Effect sizes were non-significant and close to zero for memory (d = -0.04: 95%CI -0.17 to 0.07), executive function (d = -0.05: 95%CI -0.17 to 0.05) and attention (d = -0.08: 95%CI -0.21 to 0.02). Meta-regressions showed that effect sizes were not related to participant age, duration of the trial, daily dose, total dose or sample size. CONCLUSIONS: We report that G. biloba had no ascertainable positive effects on a range of targeted cognitive functions in healthy individuals.

Paranormal beliefs and cognitive function: A systematic review and assessment of study quality across four decades of research.

BACKGROUND: Research into paranormal beliefs and cognitive functioning has expanded considerably since the last review almost 30 years ago, prompting the need for a comprehensive review. The current systematic review aims to identify the reported associations between paranormal beliefs and cognitive functioning, and to assess study quality. METHOD: We searched four databases (Scopus, ScienceDirect, SpringerLink, and OpenGrey) from inception until May 2021. Inclusion criteria comprised papers published in English that contained original data assessing paranormal beliefs and cognitive function in healthy adult samples. Study quality and risk of bias was assessed using the Appraisal tool for Cross-Sectional Studies (AXIS) and results were synthesised through narrative review. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was preregistered as part of a larger registration on the Open Science Framework (https://osf.io/uzm5v). RESULTS: From 475 identified studies, 71 (n = 20,993) met our inclusion criteria. Studies were subsequently divided into the following six categories: perceptual and cognitive biases (k = 19, n = 3,397), reasoning (k = 17, n = 9,661), intelligence, critical thinking, and academic ability (k = 12, n = 2,657), thinking style (k = 13, n = 4,100), executive function and memory (k = 6, n = 810), and other cognitive functions (k = 4, n = 368). Study quality was rated as good-to-strong for 75% of studies and appears to be improving across time. Nonetheless, we identified areas of methodological weakness including: the lack of preregistration, discussion of limitations, a-priori justification of sample size, assessment of nonrespondents, and the failure to adjust for multiple testing. Over 60% of studies have recruited undergraduates and 30% exclusively psychology undergraduates, which raises doubt about external validity. Our narrative synthesis indicates high heterogeneity of study findings. The most consistent associations emerge for paranormal beliefs with increased intuitive thinking and confirmatory bias, and reduced conditional reasoning ability and perception of randomness. CONCLUSIONS: Although study quality is good, areas of methodological weakness exist. In addressing these methodological issues, we propose that authors engage with preregistration of data collection and analysis procedures. At a conceptual level, we argue poorer cognitive performance across seemingly disparate cognitive domains might reflect the influence of an over-arching executive dysfunction.

The use of social robots with children and young people on the autism spectrum: A systematic review and meta-analysis.

BACKGROUND: Robot-mediated interventions show promise in supporting the development of children on the autism spectrum. OBJECTIVES: In this systematic review and meta-analysis, we summarize key features of available evidence on robot-interventions for children and young people on the autism spectrum aged up to 18 years old, as well as consider their efficacy for specific domains of learning. DATA SOURCES: PubMed, Scopus, EBSCOhost, Google Scholar, Cochrane Library, ACM Digital Library, and IEEE Xplore. Grey literature was also searched using PsycExtra, OpenGrey, British Library EThOS, and the British Library Catalogue. Databases were searched from inception until April (6th) 2021. SYNTHESIS METHODS: Searches undertaken across seven databases yielded 2145 articles. Forty studies met our review inclusion criteria of which 17 were randomized control trials. The methodological quality of studies was conducted with the Quality Assessment Tool for Quantitative Studies. A narrative synthesis summarised the findings. A meta-analysis was conducted with 12 RCTs. RESULTS: Most interventions used humanoid (67%) robotic platforms, were predominantly based in clinics (37%) followed home, schools and laboratory (17% respectively) environments and targeted at improving social and communication skills (77%). Focusing on the most common outcomes, a random effects meta-analysis of RCTs showed that robot-mediated interventions significantly improved social functioning (g = 0.35 [95%CI 0.09 to 0.61; k = 7). By contrast, robots did not improve emotional (g = 0.63 [95%CI -1.43 to 2.69]; k = 2) or motor outcomes (g = -0.10 [95%CI -1.08 to 0.89]; k = 3), but the numbers of trials were very small. Meta-regression revealed that age accounted for almost one-third of the variance in effect sizes, with greater benefits being found in younger children. CONCLUSIONS: Overall, our findings support the use of robot-mediated interventions for autistic children and youth, and we propose several recommendations for future research to aid learning and enhance implementation in everyday settings. PROSPERO REGISTRATION: Our methods were preregistered in the PROSPERO database (CRD42019148981).

Childhood trauma and schizotypy in non-clinical samples: A systematic review and meta-analysis.

The association of early life adversities and psychosis symptoms is well documented in clinical populations; however, whether this relationship also extends into subclinical psychosis remains unclear. In particular, are early life adversities associated with increased levels of schizotypal personality traits in non-clinical samples? We conducted a systematic review and meta-analysis of associations between early life adversities and psychometrically defined schizotypal traits in non-clinical samples. The review followed PRISMA guidelines. The search using PubMed, Web of Science and EBSCO databases identified 1,609 articles in total. Twenty-five studies (N = 15,253 participants) met eligibility criteria for the review. An assessment of study quality showed that fewer than half of all studies were rated as methodologically robust. Meta-analyses showed that all forms of childhood abuse (emotional, physical and sexual) and neglect (emotional and physical) were significantly associated with psychometric schizotypy. The association of schizotypy traits with childhood emotional abuse (r = .33: 95%CI .30 to .37) was significantly larger than for all other form of abuse or neglect. Meta-regression analyses showed that the physical abuse-schizotypy relationship was stronger in samples with more women participants; and the sexual abuse-schizotypy relationship was stronger in younger samples. The current review identifies a dose-response relationship between all forms of abuse/neglect and schizotypy scores in non-clinical samples; however, a stronger association emerged for emotional abuse. More research is required to address the relationship of trauma types and specific symptom types. Future research should also address the under-representation of men.

Prevalence and outcomes of chronic liver disease in patients receiving dialysis: systematic review and meta-analysis.

Background: Patients receiving dialysis for end-stage kidney disease (ESKD) commonly co-exhibit risk factors for hepatic impairment. This systematic review and meta-analysis aimed to quantify the coexistence of chronic liver disease (CLD) and characterize risk factors and outcomes. Methods: We searched the following databases from inception to May 2021: CINAHL, Cochrane Library, Embase, Kings Fund Library, MEDLINE and PubMed. The protocol was pre-registered on PROSPERO (study ID: CRD42020206486). Studies were assessed against three inclusion criteria: adults (>18 years) with ESKD receiving dialysis, primary outcome involving CLD prevalence and publications in English. Moderator analysis was performed for age, gender, study size and publication year. Sensitivity analysis was performed where applicable by removing outlier results and studies at high risk of bias. Results: Searches yielded 7195 articles; of these 15 met the inclusion criteria. A total of 320 777 patients were included. The prevalence of cirrhosis and non-alcoholic fatty liver disease (NAFLD) was 5% and 55%, respectively. Individuals with CLD had 2-fold higher mortality than those without {odds ratio [OR] 2.19 [95% confidence interval (CI) 1.39-3.45]}. Hepatitis B [OR 13.47 (95% CI 1.37-132.55)] and hepatitis C [OR 7.05 (95% CI 4.00-12.45)], but not diabetes, conferred increased cirrhosis risk. All studies examining NAFLD were judged to be at high risk of bias. We found no data on non-alcoholic steatohepatitis (NASH). Deaths from CLD, cancer and infection were greater among cirrhotic patients. Conclusions: CLD is prevalent in dialysis patients. Hepatitis B and C confer increased risk of CLD. The impact of NAFLD and NASH cirrhosis requires further study. CLD is associated with an increased risk of mortality in this setting.