The prodromal phase of psychosis

Gene Polymorphisms and Expression of NRG1, DAOA, and DISC1 Genes in a Chinese Han Population with an Ultra-High Risk for Psychosis

Purpose

Although there is previous evidence supporting that ultra-high risk (UHR) for psychosis transformation is associated with NRG1, DAOA, and DISC1 genes, there have been no relevant studies in the Chinese population. The objective of the current study was to explore the gene polymorphism and expression of NRG1, DAOA, and DISC1 genes in a Han population with UHR for psychosis in China.

Methods

Eighteen UHR individuals, 61 first-degree relatives of patients with schizophrenia (FDR), 55 first-episode psychosis individuals (FEP), and 61 healthy controls (HC) were enrolled in the study. The genotypes at four loci of the NRG1 gene, four loci of the DAOA gene, and two loci of the DISC1 gene were tested for all subjects, and mRNAs of NRG1 and DISC1 were examined and analyzed in a pairwise comparison among the four groups. Statistical analysis of genetics was performed using snpStats software. For the case-control association analysis, a single site association study, epistatic effect analysis, and haplotype analysis were used to explore the association of the above genes.

Results

This study found that rs3918341 in the DAOA gene was associated with susceptibility to UHR by single site association analysis. Epistatic effect analysis results showed that the NRG1 gene interacted with the DAOA gene and DISC1 gene in the susceptibility to UHR. Haplotype association analysis showed that all haplotypes were not significantly associated with UHR. NRG1 mRNA was significantly downregulated in the UHR group compared with the HC group as well as the FEP group.

Conclusion

Our preliminary results show that NRG1, DAOA, and DISC1 genes may play a role in psychosis onset, opening the way to the identification of prognostic biomarkers.

Value of P300 amplitude in the diagnosis of untreated first-episode schizophrenia and psychosis risk syndrome in children and adolescents

BACKGROUND

Identifying the characteristic neurobiological changes of early psychosis is helpful for early clinical diagnosis. However, previous studies on the brain electrophysiology of children and adolescents with psychosis are rare.

METHODS

This study compared P300 amplitude at multiple electrodes between children and adolescents with first-episode schizophrenia (FES, n = 48), children and adolescents with psychosis risk syndrome (PRS, n = 24), and healthy controls (HC, n = 30). Receiver operating characteristic (ROC) analysis was used to test the ability of P300 amplitude to distinguish FES, PRS and HC individuals.

RESULTS

The P300 amplitude in the FES group were significantly lower than those in the HC at the Cz, Pz, and Oz electrodes. The P300 amplitude was also significantly lower in the prodromal group than in the HC at the Pz and Oz electrodes. ROC curve analysis showed that at the Pz electrode, the P300 amplitude evoked by the target and standard stimulus showed high sensitivity, specificity, accuracy, and area under the curve value for distinguishing FES from HC individuals.

CONCLUSIONS

This study found early visual P300 deficits in children and adolescents with FES and PRS, with the exclusion of possible influence of medication and chronic medical conditions, suggesting the value of P300 amplitude for the identification of early psychosis.

Meta-analysis of gender differences in transition prevalence among individuals at clinical high risk of psychosis

Gender differences have been found in several areas of individuals at clinical-high risk for psychosis(CHR). Therefore the risk of transition to psychosis may differ between male and female CHR, but previous work has not systematically reviewed and analyzed gender differences in conversion rates.We performed a meta-analysis according to PRISMA guidelines including all studies that assessed CHR with reliable instruments and provided data on the transition from male CHR and female CHR to psychosis to understand the conversion rate conversion in male and female CHR. Seventy-nine article were identified.A total of 1250 out of 5770 in the male CHR individuals, and 832 out of 4468 in the female CHR individuals translated to psychotic disorders. Transition prevalence were 19.4%(95%CI:14.2-25.8%)at 1 year, 20.6% at 2 year (95%CI:17.1-24.8%),24.3% at 3 years (95%CI:21.5-27.4%),26.3% at 4 years or older (95%CI:20.9-32.5%) and 22.3% at all (95%CI:20.0-24.8%) in male CHR and 17.7% (95%CI:12.6-24.4%) at 1 years, 17.5% (95%CI:14.2-21.4%) at 2 year, 19.9%(95%CI:17.3-0.228%) at 3 years,and 0.267 (95%CI:22.1-31.9%) at 4 years or older follow-up,20.4% at all (95%CI:18.1-22.9%) in female CHR. There were differences between the two groups in the overall conversion, the 2-year, and the 3-year follow up transition prevalence, which were higher in men CHR than in female CHR. Future research characterizing male versus female CHR is needed with the expectation that interventions will be developed that are tailored to the respective gender, further reducing the rate of conversion to CHR.

Sex-specific genetic association between psychiatric disorders and cognition, behavior and brain imaging in children and adults

Although there are pronounced sex differences for psychiatric disorders, relatively little has been published on the heterogeneity of sex-specific genetic effects for these traits until very recently for adults. Much less is known about children because most psychiatric disorders will not manifest until later in life and existing studies for children on psychiatric traits such as cognitive functions are underpowered. We used results from publicly available genome-wide association studies for six psychiatric disorders and individual-level data from the Adolescent Brain Cognitive Development (ABCD) study and the UK Biobank (UKB) study to evaluate the associations between the predicted polygenic risk scores (PRS) of these six disorders and observed cognitive functions, behavioral and brain imaging traits. We further investigated the mediation effects of the brain structure and function, which showed heterogeneity between males and females on the correlation between genetic risk of schizophrenia and fluid intelligence. There was significant heterogeneity in genetic associations between the cognitive traits and psychiatric disorders between sexes. Specifically, the PRSs of schizophrenia of boys showed stronger correlation with eight of the ten cognitive functions in the ABCD data set; whereas the PRSs of autism of females showed a stronger correlation with fluid intelligence in the UKB data set. Besides cognitive traits, we also found significant sexual heterogeneity in genetic associations between psychiatric disorders and behavior and brain imaging. These results demonstrate the underlying early etiology of psychiatric disease and reveal a shared and unique genetic basis between the disorders and cognition traits involved in brain functions between the sexes.

Higher order language impairments can predict the transition of ultrahigh risk state to psychosis-An empirical study

AIM

Higher order language skills, for example, non-literal language, humour, prosody deal with 'what is meant' and they are necessary for communicative exchange and relationships; No study has investigated their link with conversion to psychosis. The purpose of this study was to determine whether such skills could act as predictors of the onset of psychosis, and compare those of individuals converting and non-converting to psychosis with control of cognitive functions.

METHODS

Seventy-three patients, aged 15 to 32 years, fulfilling ultrahigh risk criteria took part: 14% of whom were receiving antipsychotic drugs. The study was observational, prospective and longitudinal in nature, and scheduled for 60 months. Pragmatic language skills were evaluated using the Polish version of the right hemisphere language battery. The ultrahigh risk (UHR) criteria were evaluated with Comprehensive Assessment of At-Risk Mental States; attention, intelligence and verbal fluency were controlled.

RESULTS

The conversion rate was 25%; converters demonstrated impaired humour comprehension and metaphor explanation abilities; composite score of pragmatic language was associated with a hazard ratio of 6.0 (95% CI 1.8-20.5) and AUC of .73. Verbal fluency was an independent predictor of conversion, but attention and intelligence were not; pragmatic language skills were associated with social function but not with prodromal symptoms.

CONCLUSIONS

The results suggest that deficits in humour comprehension and metaphor explanation could predict conversion to psychosis. These findings could improve diagnosis and create implications for speech and language therapy in UHR groups. Further studies on the mechanisms of pragmatic skills should analyze their relationship with abstract measures and semantic coherence.

Symptom trajectories into eating disorders: A systematic review of longitudinal, nonclinical studies in children/adolescents

Background.

Eating disorders (EDs) are serious mental illnesses that can be life-threatening. Stage of illness models and early intervention strategies could be informed by a better understanding of symptomatology that precedes the onset of an ED. This review aims to explore which symptoms (both ED and other psychiatric disorder-related) exist prior to the onset of an ED and whether there any prospective associations between these symptomatologies.

Methods.

A systematic literature review was conducted in MEDLINE, Embase, and PsycINFO for large, longitudinal, prospective studies in nonclinical cohorts of children/adolescents that report symptoms prior to the onset of an ED. A quality assessment of included studies was conducted using the Newcastle-Ottawa Quality Assessment Scale.

Results.

A total of 22 studies were included, and over half were assessed to be of good quality. Studies identified the presence of a broad range of ED and other psychiatric disorder-related symptoms prior to ED onset. Possible prospective associations were identified, including early eating and feeding difficulties in childhood, to ED-related symptoms (e.g., dieting and body dissatisfaction) and other psychiatric disorder-related symptoms (e.g., anxiety and depression) in childhood/early adolescence, progressing to severe symptomatology (e.g., extreme weight control behaviors and self-harm) in mid-adolescence/emerging adulthood.

Conclusion.

The trajectory of symptoms identified to precede and possibly predict onset of an ED may inform early intervention strategies within the community. Suggestions for further research are provided to establish these findings and the clinical implications of these discussed, in order to inform how best to target prodromal stages of EDs.

Corpus callosum shape and morphology in youth across the psychosis Spectrum

The corpus callosum is the largest white matter tract in the human brain connecting and coordinating homologous regions of the right and left hemispheres and has been strongly implicated in the pathogenesis of psychosis. We investigated corpus callosum morphology in a large community cohort of 917 individuals (aged 8-21), including 267 endorsing subsyndromal or threshold psychotic symptoms (207 on the psychosis spectrum and 60 with limited psychosis based on previously published criteria) and 650 non-psychotic volunteers. We used a highly reliable and previously published algorithm to automatically identify the midsagittal plane and to align the corpus callosum along the anterior and posterior commissures for segmentation, thereby eliminating these sources of error variance in dependent measures, which included perimeter, length, mean thickness and shape (circularity). The parcellation scheme divided the corpus callosum into 7 subregions that consisted of the rostrum, genu, rostral body, anterior midbody, posterior midbody, isthmus, and splenium. Both individuals endorsing psychotic symptoms and those with limited psychosis had significantly (p<.05) smaller area and lower thickness measures compared to healthy volunteers, but did not differ significantly from each other. Findings were relatively widespread indicating a relatively global effect not circumscribed to any particular corpus callosum subregion. These data are consistent with the hypothesis that corpus callosum abnormalities may be evident early in the course of illness and predate the onset of frank psychosis. Given that these measures can be easily obtained and are highly reliable they may assist in the identification of individuals at future risk for psychosis.

Quick Identification of the Risk of Psychosis: The Italian Version of the Prodromal Questionnaire-Brief

Background:

Diagnosing people during the prodromal phase of an incipient psychosis can improve the chance of better outcome. In busy clinical settings, the ideal tool is a brief, easy-to-complete self-report questionnaire.

Objective:

To test the psychometric properties of the Italian version of one of the most used screening tools for the identification of the risk of psychosis, the Prodromal Questionnaire-Brief (PQ-B).

Methods:

Cross-sectional design. A convenience sample of college students was enrolled via snowball procedure (n=243; men: 45%). After understanding and signing the consent form, the participants received a booklet containing the following questionnaires: the 21-item Prodromal Questionnaire-Brief (PQ-B); the 12-item General Health Questionnaire (GHQ-12), and the 74-item Schizotypal Personality Questionnaire (SPQ). Receiver operating characteristic (ROC) analysis was used to assess the capacity of the PQ-B to identify individuals at risk of psychosis as independently defined based on the combination of GHQ-12 and SPQ thresholds.

Results:

The Italian version of the PQ-B revealed good internal consistency, test-retest reliability, and adequate convergent and divergent validity. The Youden method retrieved a cut-off = 7 for the PQ-B frequency score and a cut-off = 22 for the PQ-B distress score. Both PQ-B scores had a perfect (99%) negative predictive value.

Conclusion:

The PQ-B is a promising screening tool in two-stage protocols. The major advantage of the PQ-B is to exclude cases that are unlikely to be at risk of psychosis.

Deficits in the identification of pleasant odors predict the transition of an at-risk mental state to psychosis

OBJECTIVE

Existing knowledge of the relationship between olfactory identification (OI) ability and clinical risk of psychosis is inconsistent. To address this inconsistency, the aim of the present study was to identify the relationship between OI ability, with regard to the hedonic attributes of odors, and the risk of transition to psychosis in individuals with an ARMS.

METHODS

A group of 81 individuals meeting the ARMS criteria according to the Comprehensive Assessment of At Risk Mental State were at baseline administered with the University of Pennsylvania Smell Identification Test. The hedonic attributes of odorants were normatively established. Participants were followed up for transition to psychosis for a mean period of 36.1months (SD:27.5months).

RESULTS

The presence of deficits in the identification of pleasant odors was found to be a risk factor for conversion from an ARMS to schizophrenia. The hazard ratio for each point in deficit scores in the Cox regression model was 1.455 (95% CI: 1.211-1.747), p<0.0001. Significant deficits in the identification of pleasant odors were associated with a risk for conversion at both early and late time points from baseline.

CONCLUSIONS

The findings imply that the impaired identification of pleasant odorants may be a risk factor for the transition of an ARMS into a psychotic disorder, and highlights the need for further research of OI in "at-risk" cohorts, taking into account the hedonic attributes of odors.

Using Intermediate Cognitive Endpoints to Facilitate Translational Research in Psychosis

Recent advances in the understanding of psychosis have uncovered potential for a paradigm shift in related drug discovery efforts. The study of psychosis is evolving from its origins in serendipity and empiricism to more formal, hypothesis driven accounts of the cognitive substrates underlying hallucinations and delusions. Recent evidence suggests that misattribution of salience and abnormal prediction error might underlie some forms of psychosis. If substantiated, such intermediate constructs could significantly facilitate translational research for drug discovery. Aberrant salience and prediction error can be assayed with simple tests of associative learning in both species, and a convincing back translation of effects, when combined with measures of neurotransmitter release and brain activity could for the first time allow robust, causal connections to be made between molecular mechanisms in rodents and symptoms in patients.