Reduced Context Effects on Retrieval in First-Episode Schizophrenia

Background: A recent modeling study by the authors predicted that contextual information is poorly integrated into episodic representations in schizophrenia, and that this is a main cause of the retrieval deficits seen in schizophrenia. Methodology/Principal Findings: We have tested this prediction in patients with first-episode schizophrenia and matched controls. The benefit from contextual cues in retrieval was strongly reduced in patients. On the other hand, retrieval based on item cues was spared. Conclusions/Significance: These results suggest that reduced integration of context information into episodic representations is a core deficit in schizophrenia and one of the main causes of episodic memory impairment

Prescription of antipsychotic medication to patients at ultra high risk of developing psychosis

Little is known about medication prescription in a naturalistic setting to patients at ultra high risk (UHR) of developing psychosis. Antipsychotic medication prescription to UHR patients is not recommended in clinical practice guidelines based on the current evidence. The aim of this study is to investigate medication prescription to UHR patients in the Netherlands. The frequency of antipsychotic medication prescription to UHR patients (n=72) was compared with the frequency of antipsychotic medication prescription to patients who were diagnosed with a Diagnostic and Statistical Manual of Mental Disorders, fourth edition psychotic disorder at first diagnostic evaluation (n=90). Within the UHR group, frequency of antipsychotic medication prescription at baseline was compared between UHR patients who did make the transition to psychosis (n=18) and UHR patients who did not (n=54). No significant differences were found in antipsychotic medication prescription to UHR patients and to patients who turned out to have a florid psychosis: 51% in the psychotic group and 58% in the UHR group used no medication. Thirty-four percent in the psychotic group and 21% in the UHR group used antipsychotic medication. There was also no difference in medication prescription between UHR patients who did and did not make the transition to psychosis. More research should be aimed at developing and implementing clinical practice guidelines for the treatment of UHR patients

Effects of omega-3 polyunsaturated fatty acid supplementation on cognitive functioning in youth at ultra-high risk for psychosis: secondary analysis of the NEURAPRO randomised controlled trial.

BACKGROUND Cognitive impairments are well-established features of psychotic disorders and are present when individuals are at ultra-high risk for psychosis. However, few interventions target cognitive functioning in this population. AIMS To investigate whether omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation improves cognitive functioning among individuals at ultra-high risk for psychosis. METHOD Data (N = 225) from an international, multi-site, randomised controlled trial (NEURAPRO) were analysed. Participants were given omega-3 supplementation (eicosapentaenoic acid and docosahexaenoic acid) or placebo over 6 months. Cognitive functioning was assessed with the Brief Assessment of Cognition in Schizophrenia (BACS). Mixed two-way analyses of variance were computed to compare the change in cognitive performance between omega-3 supplementation and placebo over 6 months. An additional biomarker analysis explored whether change in erythrocyte n-3 PUFA levels predicted change in cognitive performance. RESULTS The placebo group showed a modest greater improvement over time than the omega-3 supplementation group for motor speed (ηp2 = 0.09) and BACS composite score (ηp2 = 0.21). After repeating the analyses without individuals who transitioned, motor speed was no longer significant (ηp2 = 0.02), but the composite score remained significant (ηp2 = 0.02). Change in erythrocyte n-3 PUFA levels did not predict change in cognitive performance over 6 months. CONCLUSIONS We found no evidence to support the use of omega-3 supplementation to improve cognitive functioning in ultra-high risk individuals. The biomarker analysis suggests that this finding is unlikely to be attributed to poor adherence or consumption of non-trial n-3 PUFAs

Proteomic Biomarkers for the Prediction of Transition to Psychosis in Individuals at Clinical High Risk: A Multi-cohort Model Development Study

Psychosis risk prediction is one of the leading challenges in psychiatry. Previous investigations have suggested that plasma proteomic data may be useful in accurately predicting transition to psychosis in individuals at clinical high risk (CHR). We hypothesized that an a priori-specified proteomic prediction model would have strong predictive accuracy for psychosis risk and aimed to replicate longitudinal associations between plasma proteins and transition to psychosis. This study used plasma samples from participants in 3 CHR cohorts: the North American Prodrome Longitudinal Studies 2 and 3, and the NEURAPRO randomized control trial (total n = 754). Plasma proteomic data were quantified using mass spectrometry. The primary outcome was transition to psychosis over the study follow-up period. Logistic regression models were internally validated, and optimism-corrected performance metrics derived with a bootstrap procedure. In the overall sample of CHR participants (age: 18.5, SD: 3.9; 51.9% male), 20.4% (n = 154) developed psychosis within 4.4 years. The a priori-specified model showed poor risk-prediction accuracy for the development of psychosis (C-statistic: 0.51 [95% CI: 0.50, 0.59], calibration slope: 0.45). At a group level, Complement C8B, C4B, C5, and leucine-rich α-2 glycoprotein 1 (LRG1) were associated with transition to psychosis but did not surpass correction for multiple comparisons. This study did not confirm the findings from a previous proteomic prediction model of transition from CHR to psychosis. Certain complement proteins may be weakly associated with transition at a group level. Previous findings, derived from small samples, should be interpreted with caution

Evidence that complement and coagulation proteins are mediating the clinical response to omega-3 fatty acids: A mass spectrometry-based investigation in subjects at clinical high-risk for psychosis.

Preliminary evidence indicates beneficial effects of omega-3 polyunsaturated fatty acids (PUFAs) in early psychosis. The present study investigates the molecular mechanism of omega-3 PUFA-associated therapeutic effects in clinical high-risk (CHR) participants. Plasma samples of 126 CHR psychosis participants at baseline and 6-months follow-up were included. Plasma protein levels were quantified using mass spectrometry and erythrocyte omega-3 PUFA levels were quantified using gas chromatography. We examined the relationship between change in polyunsaturated PUFAs (between baseline and 6-month follow-up) and follow-up plasma proteins. Using mediation analysis, we investigated whether plasma proteins mediated the relationship between change in omega-3 PUFAs and clinical outcomes. A 6-months change in omega-3 PUFAs was associated with 24 plasma proteins at follow-up. Pathway analysis revealed the complement and coagulation pathway as the main biological pathway to be associated with change in omega-3 PUFAs. Moreover, complement and coagulation pathway proteins significantly mediated the relationship between change in omega-3 PUFAs and clinical outcome at follow-up. The inflammatory protein complement C5 and protein S100A9 negatively mediated the relationship between change in omega-3 PUFAs and positive symptom severity, while C5 positively mediated the relationship between change in omega-3 and functional outcome. The relationship between change in omega-3 PUFAs and cognition was positively mediated through coagulation factor V and complement protein C1QB. Our findings provide evidence for a longitudinal association of omega-3 PUFAs with complement and coagulation protein changes in the blood. Further, the results suggest that an increase in omega-3 PUFAs decreases symptom severity and improves cognition in the CHR state through modulating effects of complement and coagulation proteins

Characterization and prediction of clinical pathways of vulnerability to psychosis through graph signal processing

Causal interactions between specific psychiatric symptoms could contribute to the heterogenous clinical trajectories observed in early psychopathology. Current diagnostic approaches merge clinical manifestations that co-occur across subjects and could significantly hinder our understanding of clinical pathways connecting individual symptoms. Network analysis techniques have emerged as alternative approaches that could help shed light on the complex dynamics of early psychopathology. The present study attempts to address the two main limitations that have in our opinion hindered the application of network approaches in the clinical setting. Firstly, we show that a multi-layer network analysis approach, can move beyond a static view of psychopathology, by providing an intuitive characterization of the role of specific symptoms in contributing to clinical trajectories over time. Secondly, we show that a Graph-Signal-Processing approach, can exploit knowledge of longitudinal interactions between symptoms, to predict clinical trajectories at the level of the individual. We test our approaches in two independent samples of individuals with genetic and clinical vulnerability for developing psychosis. Novel network approaches can allow to embrace the dynamic complexity of early psychopathology and help pave the way towards a more a personalized approach to clinical care

Is a schizo-obsessive subtype associated with cognitive impairment? Results from a large cross-sectional study in patients with psychosis and their unaffected relatives

The current study investigated whether candidate cognitive endophenotypes may be used to validate a schizo-obsessive subtype. Using within-subject random effect regression analyses and cross-trait cross-relative analyses, we evaluated the association between obsessive-compulsive symptoms (OCSs) and cognitive performance in 984 patients with nonaffective psychosis (22.5% with OCSs), 973 unaffected siblings (7.7% with OCSs), 851 parents (4.2% with OCSs), and 573 controls (4.5% with OCSs). No significant within-subject associations between OCSs and cognitive functioning were found for patients and siblings. Severity of OCSs was associated with worse set-shifting ability in parents and worse processing speed in controls, but effect sizes were small (0.10 and 0.05 respectively). Cross-trait cross-relative analyses yielded no significant results. Contrary to our expectations, neither within-subject analyses nor cross-relative analyses yielded a clear association between OCSs and cognitive performance. Results do not support a schizo-obsessive subtype associated with cognitive impairment.status: publishe

Ultra high-risk state for psychosis and non-transition: a systematic review

Most effort in ultra high-risk (UHR) research has been directed at defining the clinical and neurobiological characteristics of those UHR subjects who go on to develop psychosis. The characteristics and outcome of the remaining UHR subjects have remained relatively unexplored. We performed a systematic review of clinical UHR studies to investigate whether information was available on the characteristics and outcome of UHR subjects who did not convert to psychosis. Of 2462 potentially relevant papers, 31 met inclusion criteria, i.e. 20 naturalistic and 11 intervention studies. On average 76% (range 46-92.6%) of the UHR patients made no transition to psychosis during follow-up (range 6 to 40 months). Nearly half of the studies provided no characteristics of those UHR subjects who did not develop psychosis. Six studies reported remission rates from initial UHR status (range 15.4% to 54.3%). Linear regression showed that more recent studies reported significantly lower transition rates as compared to earlier publications. An older mean age at baseline was associated with significant lower transition rates in publications with follow-ups exceeding 1 year. Our review illustrates that the long-term outcome of UHR subjects that do not develop psychosis is to date under-investigated. The studies reporting remission rates suggest that UHR criteria capture a non-negligible proportion of subjects that do not convert to psychosi

Environmental factors and social adjustment as predictors of a first psychosis in subjects at ultra high risk

BACKGROUND: The onset of schizophrenia is associated with genetic, symptomatic, social and environmental risk factors. The aim of the present study was to determine which environmental factors may contribute to a prediction of a first psychotic episode in subjects at Ultra High Risk (UHR) for developing psychosis. METHOD: We included 72 UHR subjects and followed them over a period of 36 months, of whom nineteen (26.4%) made a transition to psychosis. We applied survival analyses to determine associations between a transition to psychosis and environmental factors and social adjustment. To determine which items are the best predictors of transition to a first psychotic episode, Cox Regression analyses were applied RESULTS: Urbanicity, receiving state benefits and poor premorbid adjustment (PMA) significantly influenced the transition to psychosis. Urbanicity (Wald = 10.096, p = .001, HR = 30.97), social-sexual aspects (Wald = 8.795, p = .003, HR = 1.91) and social-personal adjustment (Wald = 10.794, p = .001, HR = 4.26) appeared to be predictors for developing psychosis in our UHR group. CONCLUSIONS: Environmental characteristics and social adjustment are predictive of transition to a psychosis in subjects at UHR. These characteristics should be implemented in a model for prediction of psychosis. Such a model would be more specific than current models and may lead to patient-specific preventive interventions. (C) 2010 Elsevier B.V. All rights reserve

Paradigm used.

<p>Participants studied forty words with, as background, a color photograph of an indoor or outdoor scene (picture not to scale). The first test consisted of a cued recall test in which participants had to complete word stems of studied words with a word from the studied list. Half of the word stems were presented with the same scene on the background as during learning (<i>same context</i> condition), half with a different scene on the background (<i>different context</i> condition). A second test (not shown) was a word recognition test with, again, same or different scenes in the background.</p