The asymmetry of antimatter in the proton.

The fundamental building blocks of the proton-quarks and gluons-have been known for decades. However, we still have an incomplete theoretical and experimental understanding of how these particles and their dynamics give rise to the quantum bound state of the proton and its physical properties, such as its spin1. The two up quarks and the single down quark that comprise the proton in the simplest picture account only for a few per cent of the proton mass, the bulk of which is in the form of quark kinetic and potential energy and gluon energy from the strong force2. An essential feature of this force, as described by quantum chromodynamics, is its ability to create matter-antimatter quark pairs inside the proton that exist only for a very short time. Their fleeting existence makes the antimatter quarks within protons difficult to study, but their existence is discernible in reactions in which a matter-antimatter quark pair annihilates. In this picture of quark-antiquark creation by the strong force, the probability distributions as a function of momentum for the presence of up and down antimatter quarks should be nearly identical, given that their masses are very similar and small compared to the mass of the proton3. Here we provide evidence from muon pair production measurements that these distributions are considerably different, with more abundant down antimatter quarks than up antimatter quarks over a wide range of momenta. These results are expected to revive interest in several proposed mechanisms for the origin of this antimatter asymmetry in the proton that had been disfavoured by previous results4, and point to future measurements that can distinguish between these mechanisms.

Prevalence and correlates of suicidal behaviours in a representative epidemiological youth sample in Hong Kong: the significance of suicide-related rumination, family functioning, and ongoing population-level stressors.

BACKGROUND: Young people are most vulnerable to suicidal behaviours but least likely to seek help. A more elaborate study of the intrinsic and extrinsic correlates of suicidal ideation and behaviours particularly amid ongoing population-level stressors and the identification of less stigmatising markers in representative youth populations is essential. METHODS: Participants (n = 2540, aged 15-25) were consecutively recruited from an ongoing large-scale household-based epidemiological youth mental health study in Hong Kong between September 2019 and 2021. Lifetime and 12-month prevalence of suicidal ideation, plan, and attempt were assessed, alongside suicide-related rumination, hopelessness and neuroticism, personal and population-level stressors, family functioning, cognitive ability, lifetime non-suicidal self-harm, 12-month major depressive disorder (MDD), and alcohol use. RESULTS: The 12-month prevalence of suicidal ideation, ideation-only (no plan or attempt), plan, and attempt was 20.0, 15.4, 4.6, and 1.3%, respectively. Importantly, multivariable logistic regression findings revealed that suicide-related rumination was the only factor associated with all four suicidal outcomes (all p < 0.01). Among those with suicidal ideation (two-stage approach), intrinsic factors, including suicide-related rumination, poorer cognitive ability, and 12-month MDE, were specifically associated with suicide plan, while extrinsic factors, including coronavirus disease 2019 (COVID-19) stressors, poorer family functioning, and personal life stressors, as well as non-suicidal self-harm, were specifically associated with suicide attempt. CONCLUSIONS: Suicide-related rumination, population-level COVID-19 stressors, and poorer family functioning may be important less-stigmatising markers for youth suicidal risks. The respective roles played by not only intrinsic but also extrinsic factors in suicide plan and attempt using a two-stage approach should be considered in future preventative intervention work.

Impact of restrictive COVID-19 measures on daily momentary affect in an epidemiological youth sample in Hong Kong: An experience sampling study.

Restrictive COVID-19 measures can have significant mental health impacts, particularly on young people. How such measures may influence day-to-day momentary affect, nonetheless, remains to be explored. Experience sampling data were collected from 165 young people (aged 15-24) as part of a larger epidemiological youth mental health study in Hong Kong. We examined the impact of one of the most stringent COVID-19 measures - dine-in restrictions - on momentary positive and negative affect and current contexts and activities of these young people. The effects of a milder form of COVID-19 measure - school suspension - were separately examined. Multilevel analysis revealed that those in the dine-in ban group, compared to dining-as-usual, showed significantly reduced momentary positive affect (ß = -0.17, SE = 0.06, p = 0.003). Its effect remained significant even when accounting for baseline depressive and anxiety symptoms and socioeconomic status (ß = -0.15, SE = 0.05, p = 0.008). The effect of dine-in ban on reduced momentary positive affect was found specifically when participants were in indoor locations (e.g., home, office), alone, and engaged in passive leisure activities. This pattern was not observed when participants were at school or at other outdoor locations, with friends, or engaged in active leisure activities. No significant effect of school suspension on momentary affect was observed. More severe COVID-19 measures, such as dine-in ban, can have significant impacts on the momentary positive affect of young people. Certain contexts and activities may offer protection against the consequences of COVID-19 measures. The current findings may help to inform future designs of mental health interventions and public health policies. Supplementary Information: The online version contains supplementary material available at 10.1007/s12144-022-03183-y.

Triangle Singularity as the Origin of the a_{1}(1420).

The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a_{1}(1420), decaying to f_{0}(980)π. With a mass too close to and a width smaller than the axial-vector ground state a_{1}(1260), it was immediately interpreted as a new light exotic meson, similar to the X, Y, Z states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the a_{1}(1260) resonance into K^{*}(→Kπ)K[over ¯] and subsequent rescattering through a triangle singularity into the coupled f_{0}(980)π channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having fewer parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the light-meson sector that a resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect.

Performance and reading time of lung nodule identification on multidetector CT with or without an artificial intelligence-powered computer-aided detection system.

AIM: To compare the performance and reading time of different readers using automatic artificial intelligence (AI)-powered computer-aided detection (CAD) to detect lung nodules in different reading modes. MATERIALS AND METHODS: One hundred and fifty multidetector computed tomography (CT) datasets containing 340 nodules ≤10 mm in diameter were collected retrospectively. A CAD with vessel-suppressed function was used to interpret the images. Three junior and three senior readers were assigned to read (1) CT images without CAD, (2) second-read using CAD in which CAD was applied only after initial unassisted assessment, and (3) a concurrent read with CAD in which CAD was applied at the start of assessment. Diagnostic performances and reading times were compared using analysis of variance. RESULTS: For all readers, the mean sensitivity improved from 64% (95% confidence interval [CI]: 62%, 66%) for the without-CAD mode to 82% (95% CI: 80%, 84%) for the second-reading mode and to 80% (95% CI: 79%, 82%) for the concurrent-reading mode (p<0.001). There was no significant difference between the two modes in terms of the mean sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) for both junior and senior readers and all readers (p>0.05). The reading time of all readers was significantly shorter for the concurrent-reading mode (124 ± 25 seconds) compared to without CAD (156 ± 34 seconds; p<0.001) and the second-reading mode (197 ± 46 seconds; p<0.001). CONCLUSION: In CAD for lung nodules at CT, the second-reading mode and concurrent-reading mode may improve detection performance for all readers in both screening and clinical routine practice. Concurrent use of CAD is more efficient for both junior and senior readers.

Mental Health Risks after Repeated Exposure to Multiple Stressful Events during Ongoing Social Unrest and Pandemic in Hong Kong: The Role of Rumination: Risques pour la santé mentale après une exposition répétée à de multiples événements stressants d'agitation sociale durable et de pandémie à Hong Kong: le rôle de la rumination.

OBJECTIVES: The co-occurrence of different classes of population-level stressors, such as social unrest and public health crises, is common in contemporary societies. Yet, few studies explored their combined mental health impact. The aim of this study was to examine the impact of repeated exposure to social unrest-related traumatic events (TEs), coronavirus disease 2019 (COVID-19) pandemic-related events (PEs), and stressful life events (SLEs) on post-traumatic stress disorder (PTSD) and depressive symptoms, and the potential mediating role of event-based rumination (rumination of TEs-related anger, injustice, guilt, and insecurity) between TEs and PTSD symptoms. METHODS: Community members in Hong Kong who had utilized a screening tool for PTSD and depressive symptoms were invited to complete a survey on exposure to stressful events and event-based rumination. RESULTS: A total of 10,110 individuals completed the survey. Hierarchical regression analysis showed that rumination, TEs, and SLEs were among the significant predictors for PTSD symptoms (all P < 0.001), accounting for 32% of the variance. For depression, rumination, SLEs, and PEs were among the significant predictors (all P < 0.001), explaining 24.9% of the variance. Two-way analysis of variance of different recent and prior TEs showed significant dose-effect relationships. The effect of recent TEs on PTSD symptoms was potentiated by prior TEs (P = 0.005). COVID-19 PEs and prior TEs additively contributed to PTSD symptoms, with no significant interaction (P = 0.94). Meanwhile, recent TEs were also potentiated by SLEs (P = 0.002). The effects of TEs on PTSD symptoms were mediated by rumination (ß = 0.38, standard error = 0.01, 95% confidence interval: 0.36 to 0.41), with 40.4% of the total effect explained. All 4 rumination subtypes were significant mediators. CONCLUSIONS: Prior and ongoing TEs, PEs, and SLEs cumulatively exacerbated PTSD and depressive symptoms. The role of event-based rumination and their interventions should be prioritized for future research.

Search for η

We measured missing mass spectrum of the ^{12}C(γ,p) reaction for the first time in coincidence with potential decay products from η^{'} bound nuclei. We tagged an (η+p) pair associated with the η^{'}N→ηN process in a nucleus. After applying kinematical selections to reduce backgrounds, no signal events were observed in the bound-state region. An upper limit of the signal cross section in the opening angle cosθ_{lab}^{ηp}<-0.9 was obtained to be 2.2 nb/sr at the 90% confidence level. It is compared with theoretical cross sections, whose normalization ambiguity is suppressed by measuring a quasifree η^{'} production rate. Our results indicate a small branching fraction of the η^{'}N→ηN process and/or a shallow η^{'}-nucleus potential.

Inter-relationships among psychopathology, premorbid adjustment, cognition and psychosocial functioning in first-episode psychosis: a network analysis approach.

BACKGROUND: Better understanding of interplay among symptoms, cognition and functioning in first-episode psychosis (FEP) is crucial to promoting functional recovery. Network analysis is a promising data-driven approach to elucidating complex interactions among psychopathological variables in psychosis, but has not been applied in FEP. METHOD: This study employed network analysis to examine inter-relationships among a wide array of variables encompassing psychopathology, premorbid and onset characteristics, cognition, subjective quality-of-life and psychosocial functioning in 323 adult FEP patients in Hong Kong. Graphical Least Absolute Shrinkage and Selection Operator (LASSO) combined with extended Bayesian information criterion (BIC) model selection was used for network construction. Importance of individual nodes in a generated network was quantified by centrality analyses. RESULTS: Our results showed that amotivation played the most central role and had the strongest associations with other variables in the network, as indexed by node strength. Amotivation and diminished expression displayed differential relationships with other nodes, supporting the validity of two-factor negative symptom structure. Psychosocial functioning was most strongly connected with amotivation and was weakly linked to several other variables. Within cognitive domain, digit span demonstrated the highest centrality and was connected with most of the other cognitive variables. Exploratory analysis revealed no significant gender differences in network structure and global strength. CONCLUSION: Our results suggest the pivotal role of amotivation in psychopathology network of FEP and indicate its critical association with psychosocial functioning. Further research is required to verify the clinical significance of diminished motivation on functional outcome in the early course of psychotic illness.

Abnormal cognitive effort allocation and its association with amotivation in first-episode psychosis.

BACKGROUND: Abnormal effort-based decision-making represents a potential mechanism underlying motivational deficits (amotivation) in psychotic disorders. Previous research identified effort allocation impairment in chronic schizophrenia and focused mostly on physical effort modality. No study has investigated cognitive effort allocation in first-episode psychosis (FEP). METHOD: Cognitive effort allocation was examined in 40 FEP patients and 44 demographically-matched healthy controls, using Cognitive Effort-Discounting (COGED) paradigm which quantified participants' willingness to expend cognitive effort in terms of explicit, continuous discounting of monetary rewards based on parametrically-varied cognitive demands (levels N of N-back task). Relationship between reward-discounting and amotivation was investigated. Group differences in reward-magnitude and effort-cost sensitivity, and differential associations of these sensitivity indices with amotivation were explored. RESULTS: Patients displayed significantly greater reward-discounting than controls. In particular, such discounting was most pronounced in patients with high levels of amotivation even when N-back performance and reward base amount were taken into consideration. Moreover, patients exhibited reduced reward-benefit sensitivity and effort-cost sensitivity relative to controls, and that decreased sensitivity to reward-benefit but not effort-cost was correlated with diminished motivation. Reward-discounting and sensitivity indices were generally unrelated to other symptom dimensions, antipsychotic dose and cognitive deficits. CONCLUSION: This study provides the first evidence of cognitive effort-based decision-making impairment in FEP, and indicates that decreased effort expenditure is associated with amotivation. Our findings further suggest that abnormal effort allocation and amotivation might primarily be related to blunted reward valuation. Prospective research is required to clarify the utility of effort-based measures in predicting amotivation and functional outcome in FEP.

Assessment of immunization regimens of duck Riemerella anatipestifer vaccines.

AIMS: Riemerella anatipestifer infections of goslings and ducklings can result in high mortality. Since there are at least 21 serotypes of R. anatipestifer, cross-protection is an important goal for vaccine development. METHODS AND RESULTS: In this study, we evaluated the immunostimulatory effect of different immunization regimens - the traditional inactivated vaccine vs prime-boost regimens using DNA and protein subunit vaccines (DNA+subunit, subunit+subunit, subunit+inactivated and DNA+DNA). Results showed that, when compared to the inactivated vaccine, prime-boost regimens induced higher and up to 16-week longer lasting levels of antibody responses, significantly elevated the percentage of the cytotoxic CD8+ T cell and higher expression levels of IFN-γ, IL-6 and IL-12 mRNAs. Furthermore, as an indication of cross-protection, sera from prime-boost regimens were able to recognize lysates of R. anatipestifer serotypes 1, 2 and 6. CONCLUSIONS: Prime-boost regimens especially DNA-prime and protein-boost, induce strong long-term immune response and may prove protective for breeder ducks requiring long-term protection. SIGNIFICANCE AND IMPACT OF THE STUDY: It is worth mentioning that the subunit+inactivated regimen group also elicited strong immune response. The cost of this regimen may only be half of the other prime-boost regimens, making this subunit + inactivated combination an attractive option.

Predicting first-episode psychosis patients who will never relapse over 10 years.

BACKGROUND: Although relapse in psychosis is common, a small proportion of patients will not relapse in the long term. We examined the proportion and predictors of patients who never relapsed in the 10 years following complete resolution of positive symptoms from their first psychotic episode. METHOD: Patients who previously enrolled in a 12-month randomized controlled trial on medication discontinuation and relapse following first-episode psychosis (FEP) were followed up after 10 years. Relapse of positive symptoms was operationalized as a change from a Clinical Global Impression scale positive score of <3 for at least 3 consecutive months to a score of ⩾3 (mild or more severe). Baseline predictors included basic demographics, premorbid functioning, symptoms, functioning, and neurocognitive functioning. RESULTS: Out of 178 first-episode patients, 37 (21%) never relapsed during the 10-year period. Univariate predictors (p ⩽ 0.1) of patients who never relapsed included a duration of untreated psychosis (DUP) ⩽30 days, diagnosed with non-schizophrenia spectrum disorders, having less severe negative symptoms, and performing better in logical memory immediate recall and verbal fluency tests. A multivariate logistic regression analysis further suggested that the absence of any relapsing episodes was significantly related to better short-term verbal memory, shorter DUP, and non-schizophrenia spectrum disorders. CONCLUSIONS: Treatment delay and neurocognitive function are potentially modifiable predictors of good long-term prognosis in FEP. These predictors are informative as they can be incorporated into an optimum risk prediction model in the future, which would help with clinical decision making regarding maintenance treatment in FEP.

The dose-response effects of uric acid on the prevalence of metabolic syndrome and electrocardiographic left ventricular hypertrophy in healthy individuals.

BACKGROUND AND AIM: Hyperuricemia (HUA) is associated with the prevalence of metabolic syndrome (MetS) and cardiovascular risks in various populations. HUA is also able to induce cardiomyocyte hypertrophy in mouse models. However, the dose-response effects of serum uric acid (SUA) on the prevalence of MetS and electrocardiographic left ventricular hypertrophy (LVH) are unclear. METHODS AND RESULTS: We retrospectively collected data from 18,932 individuals who underwent an annual health examination between 1/1/2016 and 12/31/2016. We excluded those with systemic diseases or missing questionnaires. The primary study endpoints were the prevalence of MetS and LVH, which were defined by the criteria for the Taiwanese population and the "SPRINT" trial. The cohort consisted of 17,913 individuals with a mean age of 31.2 years (SD 7.4) and a mean body mass index of 24.6 kg/m2 (SD 3.6); 87.1% of the individuals were men. The prevalence rates of HUA, MetS, and LVH were 29.5%, 9.4%, and 0.32%, respectively, in the overall study population. The HUA group was predominantly male and had significantly poorer lifestyle choices and greater laboratory cardiometabolic biomarker values than did the normouricemic group. However, the frequencies of physical activity were comparable between the two groups. After adjusting for confounders, SUA was associated with MetS (OR:1.473, 95% CI:1.408-1.540, P < 0.001) and LVH (OR:1.301, 95% CI:1.064-1.591, P = 0.01). CONCLUSION: We demonstrated that the dose-response effects of SUA are associated with the prevalence of MetS and electrocardiographic LVH in healthy individuals from Taiwan. Based on this evidence, future studies should investigate urate-lowering therapy and cardiovascular benefits in individuals with HUA (ClinicalTrials.gov number NCT03473951).

The effect of media reporting of a homicide committed by a patient with schizophrenia on the public stigma and knowledge of psychosis among the general population of Hong Kong.

PURPOSE: This study aimed to investigate the effects of media reporting of a homicide committed by a patient with schizophrenia on the knowledge about and stigma regarding psychosis among the general Hong Kong population. The effects of using the term 'schizophrenia (jing-shen-fen-lei)' in the news on the perceptions of the new Chinese term 'psychosis (si-jue-shi-tiao)' were explored. METHODS: Random telephone surveys of the general Hong Kong population were conducted in April 2009 (1 month before the incident) and June 2009 (1 week after the incident). Stigma was measured with the Link's Perceived Discrimination-Devaluation Scale (LPDDS). Knowledge about the symptoms, treatment and belief of dangerousness of psychosis were assessed. The emotional reaction of the public to the news was explored, and its effects on knowledge and stigma were studied. RESULTS: Overall, 1016 and 506 participants completed the two surveys. More participants in the post-incident survey agreed that people with psychosis are dangerous to the public (χ2 = 4.934, p = 0.026). However, no significant differences were observed in the LPDDS scores. Participants who reported a high level of distress related to the news were more likely to perceive people with psychosis as dangerous to the public (χ2 = 6.738, p = 0.009). Women and older people reported greater distress. CONCLUSIONS: These findings suggest that media reporting of violent incidents involving people with schizophrenia increases the public belief in the dangerousness of people with psychosis but not the overall stigma. Further studies of the differential effects of violence reporting on public perceptions about people with psychosis and schizophrenia are warranted.

Differential Cross Section and Photon-Beam Asymmetry for the γ[over →]p → π

Differential cross sections and photon-beam asymmetries for the γ[over →]p→π^{-}Δ^{++}(1232) reaction have been measured for 0.7

First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process.

The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190 GeV/c π^{-} beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3 GeV/c^{2} and 8.5 GeV/c^{2}. Within the experimental uncertainties, the observed sign of the Sivers asymmetry is found to be consistent with the fundamental prediction of quantum chromodynamics (QCD) that the Sivers TMD PDFs extracted from DY have a sign opposite to the one extracted from semi-inclusive deep-inelastic scattering (SIDIS) data. We present two other asymmetries originating from the pion Boer-Mulders TMD PDFs convoluted with either the nucleon transversity or pretzelosity TMD PDFs. A recent COMPASS SIDIS measurement was obtained at a hard scale comparable to that of these DY results. This opens the way for possible tests of fundamental QCD universality predictions.

Relationship of amotivation to neurocognition, self-efficacy and functioning in first-episode psychosis: a structural equation modeling approach.

BACKGROUND: Better understanding of the complex interplay among key determinants of functional outcome is crucial to promoting recovery in psychotic disorders. However, this is understudied in the early course of illness. We aimed to examine the relationships among negative symptoms, neurocognition, general self-efficacy and global functioning in first-episode psychosis (FEP) patients using structural equation modeling (SEM). METHOD: Three hundred and twenty-one Chinese patients aged 26-55 years presenting with FEP to an early intervention program in Hong Kong were recruited. Assessments encompassing symptom profiles, functioning, perceived general self-efficacy and a battery of neurocognitive tests were conducted. Negative symptom measurement was subdivided into amotivation and diminished expression (DE) domain scores based on the ratings in the Scale for the Assessment of Negative Symptoms. RESULTS: An initial SEM model showed no significant association between functioning and DE which was removed from further analysis. A final trimmed model yielded very good model fit (χ2 = 15.48, p = 0.63; comparative fit index = 1.00; root mean square error of approximation <0.001) and demonstrated that amotivation, neurocognition and general self-efficacy had a direct effect on global functioning. Amotivation was also found to mediate a significant indirect effect of neurocognition and general self-efficacy on functioning. Neurocognition was not significantly related to general self-efficacy. CONCLUSION: Our results indicate a critical intermediary role of amotivation in linking neurocognitive impairment to functioning in FEP. General self-efficacy may represent a promising treatment target for improvement of motivational deficits and functional outcome in the early illness stage.

Gender effect on public stigma changes towards psychosis in the Hong Kong Chinese population: a comparison between population surveys of 2009 and 2014.

PURPOSE: Public stigma is an important barrier to the recovery of patients with psychosis. The current study aimed to investigate the change in stigma towards psychosis and knowledge about psychosis between 2009 and 2014 among the Chinese population in Hong Kong, with a specific focus on gender role. METHODS: Random telephone survey of general population in Hong Kong was conducted in 2009 and 2014. Stigma was measured with the revised Link's Perceived Discrimination-Devaluation Scale (LPDDS). Logistic regression was used to explore the effect of time on the change of knowledge of psychosis, and linear regression was used to explore the effect of time on the change of stigma. Change of knowledge and stigma based on gender was specifically explored. RESULTS: In total, 1016 and 1018 subjects completed the survey in 2009 and 2014, respectively. Significantly, more people agreed with medication treatment for psychosis and fewer people had misunderstanding about psychosis. However, there was no significant change in stigma levels. Males were found to have a significant deterioration of stigma (B = 0.099, SE = 0.033, ß = 0.100, p = 0.003) but not females. Significantly, more males endorsed medication treatment for psychosis (χ 2 = 5.850, df = 1, p = 0.016) but no change for females (χ 2 = 1.401, df = 1, p = 0.238). CONCLUSIONS: Results of this study suggested that there was an improvement in the biological understanding of psychosis but no change of public stigma within the Hong Kong Chinese population. The specific role of gender in relation to stigma and level of knowledge about psychosis indicates that this should be a consideration in designing future anti-stigma campaigns.

Interference Effect between ϕ and Λ(1520) Production Channels in the γp→K

The ϕ-Λ(1520) interference effect in the γp→K^{+}K^{-}p reaction has been measured for the first time in the energy range from 1.673 to 2.173 GeV. The relative phases between ϕ and Λ(1520) production amplitudes were obtained in the kinematic region where the two resonances overlap. The measurement results support strong constructive interference when K^{+}K^{-} pairs are observed at forward angles but destructive interference for proton emission at forward angles. Furthermore, the observed interference effect does not account for the sqrt[s]=2.1 GeV bump structure in forward differential cross sections for ϕ photoproduction. This fact suggests possible exotic structures such as a hidden-strangeness pentaquark state, a new Pomeron exchange, or rescattering processes via other hyperon states.

Visual working memory deterioration preceding relapse in psychosis.

BACKGROUND: Relapse is distressingly common after the first episode of psychosis, yet it is poorly understood and difficult to predict. Investigating changes in cognitive function preceding relapse may provide new insights into the underlying mechanism of relapse in psychosis. We hypothesized that relapse in fully remitted first-episode psychosis patients was preceded by working memory deterioration. METHOD: Visual memory and verbal working memory were monitored prospectively in a 1-year randomized controlled trial of remitted first-episode psychosis patients assigned to medication continuation (quetiapine 400 mg/day) or discontinuation (placebo). Relapse (recurrence of positive symptoms of psychosis), visual (Visual Patterns Test) and verbal (Letter-Number span test) working memory and stressful life events were assessed monthly. RESULTS: Remitted first-episode patients (n = 102) participated in the study. Relapsers (n = 53) and non-relapsers (n = 49) had similar baseline demographic and clinical profiles. Logistic regression analyses indicated relapse was associated with visual working memory deterioration 2 months before relapse [odds ratio (OR) 3.07, 95% confidence interval (CI) 1.19-7.92, P = 0.02], more stressful life events 1 month before relapse (OR 2.11, 95% CI 1.20-3.72, P = 0.01) and medication discontinuation (OR 5.52, 95% CI 2.08-14.62, P = 0.001). CONCLUSIONS: Visual working memory deterioration beginning 2 months before relapse in remitted first-episode psychosis patients (not baseline predictor) may reflect early brain dysfunction that heralds a psychotic relapse. The deterioration was found to be unrelated to a worsening of psychotic symptoms preceding relapse. Testable predictors offer insight into the brain processes underlying relapse in psychosis.