International Consensus on Standard Outcome Measures for Neurodevelopmental Disorders: A Consensus Statement.

Importance: The use of evidence-based standardized outcome measures is increasingly recognized as key to guiding clinical decision-making in mental health. Implementation of these measures into clinical practice has been hampered by lack of clarity on what to measure and how to do this in a reliable and standardized way. Objective: To develop a core set of outcome measures for specific neurodevelopmental disorders (NDDs), such as attention-deficit/hyperactivity disorder (ADHD), communication disorders, specific learning disorders, and motor disorders, that may be used across a range of geographic and cultural settings. Evidence Review: An international working group composed of clinical and research experts and service users (n = 27) was convened to develop a standard core set of accessible, valid, and reliable outcome measures for children and adolescents with NDDs. The working group participated in 9 video conference calls and 8 surveys between March 1, 2021, and June 30, 2022. A modified Delphi approach defined the scope, outcomes, included measures, case-mix variables, and measurement time points. After development, the NDD set was distributed to professionals and service users for open review, feedback, and external validation. Findings: The final set recommends measuring 12 outcomes across 3 key domains: (1) core symptoms related to the diagnosis; (2) impact, functioning, and quality of life; and (3) common coexisting problems. The following 14 measures should be administered at least every 6 months to monitor these outcomes: ADHD Rating Scale 5, Vanderbilt ADHD Diagnostic Rating Scale, or Swanson, Nolan, and Pelham Rating Scale IV; Affective Reactivity Index; Children's Communication Checklist 2; Colorado Learning Disabilities Questionnaire; Children's Sleep Habits Questionnaire; Developmental-Disability Children's Global Assessment Scale; Developmental Coordination Disorder Questionnaire; Family Strain Index; Intelligibility in Context Scale; Vineland Adaptive Behavior Scale or Repetitive Behavior Scale-Revised and Social Responsiveness Scale; Revised Child Anxiety and Depression Scales; and Yale Global Tic Severity Scale. The external review survey was completed by 32 professionals and 40 service users. The NDD set items were endorsed by more than 70% of professionals and service users in the open review survey. Conclusions and Relevance: The NDD set covers outcomes of most concern to patients and caregivers. Use of the NDD set has the potential to improve clinical practice and research.

Placebo effects in randomized trials of pharmacological and neurostimulation interventions for mental disorders: An umbrella review.

There is a growing literature exploring the placebo response within specific mental disorders, but no overarching quantitative synthesis of this research has analyzed evidence across mental disorders. We carried out an umbrella review of meta-analyses of randomized controlled trials (RCTs) of biological treatments (pharmacotherapy or neurostimulation) for mental disorders. We explored whether placebo effect size differs across distinct disorders, and the correlates of increased placebo effects. Based on a pre-registered protocol, we searched Medline, PsycInfo, EMBASE, and Web of Knowledge up to 23.10.2022 for systematic reviews and/or meta-analyses reporting placebo effect sizes in psychopharmacological or neurostimulation RCTs. Twenty meta-analyses, summarising 1,691 RCTs involving 261,730 patients, were included. Placebo effect size varied, and was large in alcohol use disorder (g = 0.90, 95% CI [0.70, 1.09]), depression (g = 1.10, 95% CI [1.06, 1.15]), restless legs syndrome (g = 1.41, 95% CI [1.25, 1.56]), and generalized anxiety disorder (d = 1.85, 95% CI [1.61, 2.09]). Placebo effect size was small-to-medium in obsessive-compulsive disorder (d = 0.32, 95% CI [0.22, 0.41]), primary insomnia (g = 0.35, 95% CI [0.28, 0.42]), and schizophrenia spectrum disorders (standardized mean change = 0.33, 95% CI [0.22, 0.44]). Correlates of larger placebo response in multiple mental disorders included later publication year (opposite finding for ADHD), younger age, more trial sites, larger sample size, increased baseline severity, and larger active treatment effect size. Most (18 of 20) meta-analyses were judged 'low' quality as per AMSTAR-2. Placebo effect sizes varied substantially across mental disorders. Future research should explore the sources of this variation. We identified important gaps in the literature, with no eligible systematic reviews/meta-analyses of placebo response in stress-related disorders, eating disorders, behavioural addictions, or bipolar mania.

Problematic pornography use and novel patterns of escalating use: A cross-sectional network analysis with two independent samples.

Modern internet pornography allows users to harness sexual novelty in numerous ways, which can be used to overcome desensitisation through increasing volume of use (quantitative tolerance), progressing to more stimulating genres (qualitative escalation), skipping between stimuli (tab-jumping), delaying orgasm ('edging'), and engaging in pornographic binges. However, existing research has not yet evaluated how these potentially reciprocal consumption patterns relate to problematic pornography use (PPU). To this end, we recruited two independent samples of male pornography users (N1 = 1,356, Mage = 36.86, SD = 11.26; N2 = 944, Mage = 38.69, SD = 12.26) and examined the relationships between these behavioural dimensions and self-reported difficulties in controlling one's pornography use. Data were analysed through the network analysis approach (using Gaussian graphical models). As hypothesised, i) quantitative tolerance was centrally placed within the overall network, and ii) acted as a statistical bridge node between other patterns of pornography use (e.g., pornographic binges), and all measured facets of PPU. Our results are consistent with other emerging literature suggesting that tolerance, pornographic binges, tab-jumping, and edging behaviours as relevant features ofPPU, and that upscaling overall usage may connect broader patterns of use with problematic engagement. Clinical and theoretical implications, as well as future research directions, are discussed.

Examining the unique relationships between problematic use of the internet and impulsive and compulsive tendencies: network approach.

BACKGROUND: Both impulsivity and compulsivity have been identified as risk factors for problematic use of the internet (PUI). Yet little is known about the relationship between impulsivity, compulsivity and individual PUI symptoms, limiting a more precise understanding of mechanisms underlying PUI. AIMS: The current study is the first to use network analysis to (a) examine the unique association among impulsivity, compulsivity and PUI symptoms, and (b) identify the most influential drivers in relation to the PUI symptom community. METHOD: We estimated a Gaussian graphical model consisting of five facets of impulsivity, compulsivity and individual PUI symptoms among 370 Australian adults (51.1% female, mean age = 29.8, s.d. = 11.1). Network structure and bridge expected influence were examined to elucidate differential associations among impulsivity, compulsivity and PUI symptoms, as well as identify influential nodes bridging impulsivity, compulsivity and PUI symptoms. RESULTS: Results revealed that four facets of impulsivity (i.e. negative urgency, positive urgency, lack of premeditation and lack of perseverance) and compulsivity were related to different PUI symptoms. Further, compulsivity and negative urgency were the most influential nodes in relation to the PUI symptom community due to their highest bridge expected influence. CONCLUSIONS: The current findings delineate distinct relationships across impulsivity, compulsivity and PUI, which offer insights into potential mechanistic pathways and targets for future interventions in this space. To realise this potential, future studies are needed to replicate the identified network structure in different populations and determine the directionality of the relationships among impulsivity, compulsivity and PUI symptoms.

Lifetime alcohol use disorder and gambling disorder: clinical profile and treatment response.

OBJECTIVES: Gambling disorder affects 0.5-2.4% of the population and shows strong associations with lifetime alcohol use disorder. Very little is known regarding whether lifetime alcohol use disorder can impact the clinical presentation or outcome trajectory of gambling disorder. METHODS: Data were pooled from previous clinical trials conducted on people with gambling disorder, none of whom had current alcohol use disorder. Demographic and clinical variables were compared between those who did versus did not have lifetime alcohol use disorder. RESULTS: Of the 621 participants in the clinical trials, 103 (16.6%) had a lifetime history of alcohol use disorder. History of alcohol use disorder was significantly associated with male gender (relative risk [RR] = 1.42), greater body weight (Cohen's D = 0.27), family history of alcohol use disorder in first-degree relative(s) (RR = 1.46), occurrence of previous hospitalization due to psychiatric illness (RR = 2.68), and higher gambling-related legal problems (RR = 1.50). History of alcohol use disorder was not significantly associated with other variables that were examined, such as severity of gambling disorder or extent of functional disability. Lifetime alcohol use disorder was not significantly associated with the extent of clinical improvement in gambling disorder symptoms during the subsequent clinical trials. CONCLUSIONS: These data highlight that lifetime alcohol use disorder is an important clinical variable to be considered when assessing gambling disorder because it is associated with several untoward features (especially gambling-related legal problems and prior psychiatric hospitalization). The study design enabled these associations to be disambiguated from current or recent alcohol use disorder.

Emotion regulation across psychiatric disorders.

OBJECTIVE: Difficulties with emotion regulation have been associated with multiple psychiatric conditions. In this study, we aimed to investigate emotional regulation difficulties in young adults who gamble at least occasionally (ie, an enriched sample), and diagnosed with a range of psychiatric disorders using the validated Difficulties in Emotion Regulation Scale (DERS). METHODS: A total of 543 non-treatment-seeking individuals who had engaged in gambling activities on at least 5 occasions within the previous year, aged 18-29 were recruited from general community settings. Diagnostic assessments included the Mini International Neuropsychiatric Inventory, Minnesota Impulsive Disorders Interview, attention-deficit/hyperactivity disorder World Health Organization Screening Tool Part A, and the Structured Clinical Interview for Gambling Disorder. Emotional dysregulation was evaluated using DERS. The profile of emotional dysregulation across disorders was characterized using Z-scores (those with the index disorder vs. those without the index disorder). RESULTS: Individuals with probable ADHD displayed the highest level of difficulties in emotional regulation, followed by intermittent explosive disorder, social phobia, and generalized anxiety disorder. In contrast, participants diagnosed with obsessive-compulsive disorder showed relatively lower levels of difficulties with emotional regulation. CONCLUSIONS: This study highlights the importance of recognizing emotional dysregulation as a trans-diagnostic phenomenon across psychiatric disorders. The results also reveal differing levels of emotional dysregulation across diagnoses, with potential implications for tailored treatment approaches. Despite limitations such as small sample sizes for certain disorders and limited age range, this study contributes to a broader understanding of emotional regulation's role in psychiatric conditions.

Differential effects of sertraline and cognitive behavioural therapy on behavioural inhibition in patients with obsessive compulsive disorder.

Patients with obsessive compulsive disorder (OCD) randomised to sertraline, manualised cognitive behavioural therapy (CBT), or combination (sertraline + CBT), underwent cognitive assessment. Cognitive testing was conducted at baseline and at week 16. The stop signal reaction time task (SSRT) was used to evaluate motor impulsivity and attentional flexibility was evaluated using the intra/extra-dimensional set shifting task. Paired-samples t -tests or nonparametric variants were used to compare baseline and posttreatment scores within each treatment group. Forty-five patients were tested at baseline (sertraline n  = 14; CBT n  = 14; sertraline + CBT n  = 17) and 23 patients at week 16 (sertraline n  = 6; CBT n  = 7; sertraline + CBT n  = 10). The mean dosage of sertraline was numerically higher in those taking sertraline as a monotherapy (166.67 mg) compared with those taking sertraline in combination with CBT (100 mg). Analysis of pre-post treatment scores using an intent-to-treat-analysis found a significant reduction in the SSRT in those treated with sertraline, whilst there was no significant change on this task for those treated with CBT or the combination. This study found that motor inhibition improved significantly following sertraline monotherapy. Suboptimal sertraline dosing might explain the failure to detect an effect on motor inhibition in the group receiving combination of sertraline + CBT. Higher dose sertraline may have broader cognitive effects than CBT for OCD, motor impulsivity may have value as a measure of treatment outcome and, by extension, the SSRT could serve as a biomarker for personalising care.

Silymarin (Milk Thistle) Treatment of Adults With Gambling Disorder: A Double-Blind, Placebo-Controlled Trial.

OBJECTIVE: Data on the pharmacological treatment of gambling disorder are limited. Silymarin (derived from milk thistle) has antioxidant properties. The goal of the current study was to determine the efficacy and tolerability of silymarin in adults with gambling disorder. METHODS: Forty-three individuals (18 [41.9%] women; mean age=49.61 [±13.1] years) with gambling disorder entered an 8-week, double-blind, placebo-controlled study. Dosing of silymarin ranged from 150 to 300 mg twice a day. The primary outcome measure was the Yale Brown Obsessive Compulsive Scale Modified for Pathological Gambling (PG-YBOCS). Secondary outcome measures comprised the Gambling Symptom Assessment Scale and measures of depression and anxiety. Outcomes were examined using mixed-effect models. RESULTS: Silymarin did not statistically differentiate from the placebo on any of the outcome measures of interest, in terms of treatment group×time interactions. There was a robust response in the placebo group (57% reduction on the PG-YBOCS), and on average there was a 56% reduction in YBOCS score for the milk thistle. CONCLUSIONS: The findings of this study do not support the use of silymarin/milk thistle in the treatment of gambling disorder but highlight the large placebo response seen in gambling disorder. Treatment interventions for gambling disorder need to better understand and address the placebo response. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02337634.

Treatment discontinuation in pharmacological clinical trials for gambling disorder.

BACKGROUND: Gambling disorder affects 0.5-2% of the population, and of those who receive treatment, dropout tends to be relatively high. Very little is known about participant-specific variables linked to treatment discontinuation/dropout in gambling disorder, especially in pharmacological clinical trial settings. METHODS: Data were pooled from eight previous randomized, controlled pharmacological clinical trials conducted in people with gambling disorder. Demographic and clinical variables were compared between those who did versus did not subsequently dropout from those treatment trials. RESULTS: The sample comprised data from 635 individuals, and the overall rate of treatment dropout was 40%. Subsequent treatment dropout was significantly associated with the following: positive family history of gambling disorder in one or more first degree relatives (relative risk [RR] of dropout in those with positive history vs not = 1.30), preference for mainly strategic vs non-strategic gambling activities (RR = 1.43), lower levels of education (Cohen's D = 0.22), and higher levels of functional disability (Cohen's D = 0.18). These variables did not differ significantly as a function of treatment condition (medication versus placebo). Dropouts and completers did not differ significantly in terms of the other demographic or clinical variables that were considered. CONCLUSIONS: This study identified several candidate participant-specific predictors of pharmacological treatment dropout in gambling disorder. The findings highlight the need for future studies to address a wider range of contextual variables at large scale (including also study-specific variables e.g. trial/intervention duration), including in naturalistic treatment and clinical trial settings, with a view to developing algorithms that might usefully predict dropout risk.

Family functioning and problematic usage of the internet in youth: A cross-sectional investigation.

BACKGROUND: Problematic usage of the internet (PUI) refers to maladaptive use of the Internet linked to functional impairment as a growing concern in many countries. Youths are often considered more vulnerable to PUI than other age groups. The relationship between PUI and family dynamics is likely bidirectional and complex, warranting further research. Using a cross-sectional study design, we aimed to determine the rate of PUI and the association between PUI and family functioning in a South African sample between the ages of 18 and 30 years. METHODS: South African youths were recruited via email and social media. Respondents completed an online survey as part of a cross-sectional study to assess the extent and the types of activities for which they use the internet, as well as the quality of their family relationships and functioning, employing standardised questionnaires (including the IAT-10) and the General Functioning Scale of the Family Assessment Device (GF-FAD). The sample included 814 participants (65% female; aged 21 years; SD 3 years). RESULTS: 15.5% of our sample presented with PUI. There was a significant, moderate positive correlation between totals on the IAT-10 and GF-FAD (r = 0.33, p < .001). An independent samples t-test found that individuals with self-reported PUI (GF-FAD: M = 2.57, SD = 0.51) had significantly poorer quality family functioning than individuals without PUI (GF-FAD: M = 2.13, SD = 0.61; t (812) = -7.52, p < .001; Cohen's d = -0.73, 95% CI [-0.92, -0.54]). Correlations were found between increased time spent on various online activities, including pornography (r = 0.20, p < 0.001), cyberbullying (r = 0.17, p < 0.001), social networking (r = 0.11, p = 0.003), and streaming media (r = 0.11, p = 0.003), and poorer quality family functioning. CONCLUSION: PUI is common in South African youth. Presence of PUI and increased PUI severity were associated with worse family functioning in this sample. We recommend using family-based approaches in promoting a healthy family environment, and in the prevention of PUI and mitigation of its effects, with the goal of striking a balance between the benefits of the internet and its potential role in compromising aspects of family relationships.

Cognition in trichotillomania: a meta-analysis.

OBJECTIVE: Trichotillomania (TTM) is a mental health disorder characterized by repetitive urges to pull out one's hair. Cognitive deficits have been reported in people with TTM compared to controls; however, the current literature is sparse and inconclusive about affected domains. We aimed to synthesize research on cognitive functioning in TTM and investigate which cognitive domains are impaired. METHODS: After preregistration on the International Prospective Register of Systematic Reviews (PROSPERO), we conducted a comprehensive literature search for papers examining cognition in people with TTM versus controls using validated tests. A total of 793 papers were screened using preestablished inclusion/exclusion criteria, yielding 15 eligible studies. Random-effects meta-analysis was conducted for 12 cognitive domains. RESULTS: Meta-analysis demonstrated significant deficits in motor inhibition and extradimensional (ED) shifting in people with TTM versus controls as measured by the stop-signal task (SST) (Hedge's g = 0.45, [CI: 0.14, 0.75], p = .004) and ED set-shift task (g = 0.38, [CI: 0.13, 0.62], p = .003), respectively. There were no significant between-group differences in the other cognitive domains tested: verbal learning, intradimensional (ID) shifting, road map spatial ability, pattern recognition, nonverbal memory, executive planning, spatial span length, Stroop inhibition, Wisconsin card sorting, and visuospatial functioning. Findings were not significantly moderated by study quality scores. CONCLUSIONS: Motor inhibition and ED set-shifting appear impaired in TTM. However, a cautious interpretation of results is necessary as samples were relatively small and frequently included comorbidities. Treatment interventions seeking to improve inhibitory control and cognitive flexibility merit exploration for TTM.

A systematic review of the cognitive effects of the COMT inhibitor, tolcapone, in adult humans.

OBJECTIVE: The catechol-o-methyltransferase (COMT) inhibitor tolcapone constitutes a potentially useful probe of frontal cortical dopaminergic function. The aim of this systematic review was to examine what is known of effects of tolcapone on human cognition in randomized controlled studies. METHODS: The study protocol was preregistered on the Open Science Framework. A systematic review was conducted using PubMed to identify relevant randomized controlled trials examining the effects of tolcapone on human cognition. Identified articles were then screened against inclusion and exclusion criteria. RESULTS: Of the 22 full-text papers identified, 13 randomized control trials were found to fit the pre-specified criteria. The most consistent finding was that tolcapone modulated working memory; however, the direction of effect appeared to be contingent on the COMT polymorphism (more consistent evidence of improvement in Val-Val participants). There were insufficient nature and number of studies for meta-analysis. CONCLUSION: The cognitive improvements identified upon tolcapone administration, in some studies, are likely to be due to the level of dopamine in the prefrontal cortex being shifted closer to its optimum, per an inverted U model of prefrontal function. However, the results should be interpreted cautiously due to the small numbers of studies. Given the centrality of cortical dopamine to understanding human cognition, studies using tolcapone in larger samples and across a broader set of cognitive domains would be valuable. It would also be useful to explore the effects of different dosing regimens (different doses; and single versus repeated administration).

Genetics of gambling disorder and related phenotypes: The potential uses of polygenic and multifactorial risk models to enable early detection and improve clinical outcomes.

Gambling Disorder (GD) is an impactful behavioural addiction for which there appear to be underpinning genetic contributors. Twin studies show significant GD heritability results and intergenerational transmission show high rates of transmission. Recent developments in polygenic and multifactorial risk prediction modelling provide promising opportunities to enable early identification and intervention for at risk individuals. People with GD often have significant delays in diagnosis and subsequent help-seeking that can compromise their recovery. In this paper we advocate for more research into the utility of polygenic and multifactorial risk modelling in GD research and treatment programs and rigorous evaluation of its costs and benefits.

The neurocognitive correlates of non-substance addictive behaviors.

Neurocognitive deficits have been implicated as transdiagnostic risk markers of substance use disorders. However, these have yet to be comprehensively evaluated in other, non-substance addictions. In a large, general community sample (N = 475) the present study evaluated the neurocognitive correlates of problem alcohol use and three non-substance-related addictive behaviors: addictive eating (AE), problematic pornography use (PPU), and problematic use of the internet (PUI), to identify potential shared and distinct neurocognitive correlates. A sample of Australian residents (54.4 % female M[SD] age = 32.4[11.9] years) completed a comprehensive online assessment of neurocognitive tasks tapping into eight distinct expert-endorsed domains purportedly associated with addiction. Multiple linear regressions with bootstrapping were used to examine associations among each addictive behavior of interest and neurocognition, trait impulsivity, and compulsivity, as well as key covariates. Neurocognition was differentially associated with each addictive behavior. None of the neurocognitive domains were significantly associated with problematic alcohol use or AE (p >.05), poorer performance monitoring was significantly associated with higher levels of PPU and PUI (ß = -0.10, p =.049; ß = -0.09, p =.028), and a preference for delayed gratification was associated with more severe PUI (ß = -0.10, p =.025). Our findings have theoretical implications for how we understand non-substance addiction and suggest the need for a more nuanced approach to studying addictive behaviors that take into account the underlying neurocognitive mechanisms associated with each type of addiction.

Duration of untreated illness in gambling disorder.

OBJECTIVE: Gambling disorder is common, affects 0.5-2% of the population, and is under-treated. Duration of untreated illness (DUI) has emerged as a clinically important concept in the context of other mental disorders, but DUI in gambling disorder, has received little research scrutiny. METHODS: Data were aggregated from previous clinical trials in gambling disorder with people who had never previously received any treatment. DUI was quantified, and clinical characteristics were compared as a function of DUI status. RESULTS: A total of 298 individuals were included, and the mean DUI (standard deviation) was 8.9 (8.4) years, and the median DUI was 6 years. Longer DUI was significantly associated with male gender, older age, earlier age when the person first started to gamble, and family history of alcohol use disorder. Longer DUI was not significantly associated with racial-ethnic status, gambling symptom severity, current depressive or anxiety severity, comorbidities, or disability/functioning. The two groups did not differ in their propensity to drop out of the clinical trials, nor in overall symptom improvement associated with participation in those trials. CONCLUSIONS: These data suggest that gambling disorder has a relatively long DUI and highlight the need to raise awareness and foster early intervention for affected and at-risk individuals. Because earlier age at first gambling in any form was strongly linked to longer DUI, this highlights the need for more rigorous legislation and education to reduce exposure of younger people to gambling.

Disorders of impulsivity in trichotillomania and skin picking disorder.

Trichotillomania and skin picking disorder are often classified as body-focused repetitive behaviors (BFRBs) as they are characterized by repetitive hair-pulling and skin picking, respectively. They were initially considered to be impulse control disorders despite little research scrutiny. The objective of this study was to examine the relationship of these two conditions to other disorders with impulsive features. Adults with trichotillomania (n = 104) and skin picking (n = 178) or both (n = 96) were recruited from the general community using advertisements and online support groups and completed an online survey. Participants undertook a structured clinical interview and completion of self-report instruments to characterize clinical profiles and associated characteristics. In addition, each participant completed the Minnesota Impulse Disorders Interview to screen for disorders with impulsive features. Of the 378 adults with BFRBs, 134 (35.4%) screened positive for at least one disorder with features of impulsivity with the most common being compulsive buying (18.3%) and problematic use of the internet (17.5%). Participants with a co-occurring disorder of impulsivity reported significantly worse pulling and picking symptoms (p < .001), were more likely to have co-occurring alcohol problems (p < .001) and PTSD (p < .001), and scored higher regarding dissociative symptoms (p < .001). BFRBs are associated with a range of impulsive disorders and the comorbidity may have important treatment implications.

Placebo effects in mental health disorders: protocol for an umbrella review.

INTRODUCTION: Given the high prevalence of mental health disorders and their significant socioeconomic burden, there is a need to develop improved treatments, and to evaluate them through placebo-controlled trials. However, the magnitude of the placebo response in randomised controlled trials to test medications may be substantial, affecting their interpretation. Therefore, improved understanding of the patient, trial and mental disorder factors that influence placebo responses would inform clinical trial design to better detect active treatment effects. There is a growing literature exploring the placebo response within specific mental health disorders, but no overarching synthesis of this research has been produced to date. We present a protocol for an umbrella review of systematic reviews and/or meta-analyses in which we aim to understand the effect size and potential predictors of placebo response within, and across, mental health disorders. METHODS AND ANALYSIS: We will systematically search databases (Medline, PsycINFO, EMBASE+EMBASE Classic, Web of Knowledge) for systematic reviews and/or meta-analyses that report placebo effect size in clinical trials in patients with mental health disorders (initial search date 23 October 2022). Screening of abstracts and full texts will be done in pairs. We will extract data to qualitatively examine how placebo effect size varies across mental health disorders. We also plan to qualitatively summarise predictors of increased placebo response identified either quantitatively (eg, through meta-regression) or qualitatively. Risk of bias will be assessed using the AMSTAR-2 tool. We aim to not only summarise the current literature but also to identify gaps in knowledge and generate further hypotheses. ETHICS AND DISSEMINATION: We do not believe there are any specific ethical considerations relevant to this study. We will publish the results in a peer-reviewed journal.

Clarifying and extending our understanding of problematic pornography use through descriptions of the lived experience.

Problematic pornography use (PPU) is a complex and growing area of research. However, knowledge of the PPU lived experience is limited. To address this gap, we conducted an online qualitative study with 67 individuals who self-identified as having problematic pornography use (76% male; Mage = 24.70 years, SD = 8.54). Results indicated several dimensions that have not been fully explored in the literature. These included various mental and physical complaints following periods of heavy pornography use, sexual functioning deficits with real partners, and a subjectively altered state of sexual arousal while using pornography. Moreover, we expanded on current knowledge regarding the inner conflict associated with PPU and clarified the ways that users can progress to increasingly intensified patterns of pornography use, such as tolerance/escalation and pornographic binges. Our study highlights the complex and nuanced nature of PPU and provides suggestions for future research and clinical practice.

Conceptualising compulsivity through network analysis: A two-sample study.

Compulsivity is a transdiagnostic construct crucial to understanding multiple psychiatric conditions and problematic repetitive behaviours. Despite being identified as a clinical- and research-relevant construct, there are limited insights into the internal conceptual structure of compulsivity. To provide a more nuanced understanding of compulsivity, the current study estimated the structure of compulsivity (indexed using the previously validated Cambridge-Chicago Compulsivity Trait Scale, CHI-T) among two large-scale and geographically distinct samples using the network estimation method. The samples consisted of a United Kingdom cohort (n = 122,346, 51.4% female, Mean age = 43.7, SD = 16.5, range = 9-86 years) and a South Africa cohort (n = 2674, 65.6% female, Mean age = 24.6, SD = 8.6, range = 18-65 years). Network community analysis demonstrated that compulsivity was constituted of three interrelated dimensions, namely: perfectionism, cognitive rigidity and reward drive. Further, 'Completion leads to soothing' and 'Difficulty moving from task to task' were identified as core (central nodes) to compulsivity. The dimensional structure and central nodes of compulsivity networks were consistent across the two samples. These findings facilitate the conceptualisation and measurement of compulsivity and may contribute to the early detection and treatment of compulsivity-related disorders.