Heterogeneous trajectories in schizophrenia: insights from neurodevelopment and neuroprogression models

Biomarkers of neurodegeneration in schizophrenia: systematic review and meta-analysis

QUESTION

Does neurodegenerative disease underlie the increased rate of dementia observed in older people with schizophrenia? Several studies have reported a higher prevalence of dementia in people with schizophrenia compared with the general population. This may reflect a higher risk of developing neurodegenerative diseases such as vascular dementia or Alzheimer's disease (AD). Alternatively, this may reflect non-pathological, age-related cognitive decline in a population with low cognitive reserve.

STUDY SELECTION AND ANALYSIS

We reviewed papers that compared postmortem findings, hippocampal MRI volume or cerebrospinal fluid (CSF) markers of AD, between patients with schizophrenia with evidence of cognitive impairment (age ≥45 years) with controls. We subsequently performed a meta-analysis of postmortem studies that compared amyloid-β plaques (APs) or neurofibrillary tangles (NFTs) in cognitively impaired patients with schizophrenia to normal controls or an AD group.

FINDINGS

No studies found a significant increase of APs or NFTs in cognitively impaired patients with schizophrenia compared with controls. All postmortem studies that compared APs or NFTs in patients with schizophrenia to an AD group found significantly more APs or NFTs in AD. No studies found a significant differences in CSF total tau or phosphorylated tau between patients with schizophrenia and controls. The two studies which compared CSF Aβ42 between patients with schizophrenia and controls found significantly decreased CSF Aβ42 in schizophrenia compared with controls. Hippocampal volume findings were mixed.

CONCLUSIONS

Studies have not found higher rates of AD-related pathology in cognitively impaired individuals with schizophrenia compared with controls. Higher rates of dementia identified in population studies may reflect a lack of specificity in clinical diagnostic tools used to diagnose dementia.

The schizophrenia syndrome, circa 2024: What we know and how that informs its nature

With new data about different aspects of schizophrenia being continually generated, it becomes necessary to periodically revisit exactly what we know. Along with a need to review what we currently know about schizophrenia, there is an equal imperative to evaluate the construct itself. With these objectives, we undertook an iterative, multi-phase process involving fifty international experts in the field, with each step building on learnings from the prior one. This review assembles currently established findings about schizophrenia (construct, etiology, pathophysiology, clinical expression, treatment) and posits what they reveal about its nature. Schizophrenia is a heritable, complex, multi-dimensional syndrome with varying degrees of psychotic, negative, cognitive, mood, and motor manifestations. The illness exhibits a remitting and relapsing course, with varying degrees of recovery among affected individuals with most experiencing significant social and functional impairment. Genetic risk factors likely include thousands of common genetic variants that each have a small impact on an individual's risk and a plethora of rare gene variants that have a larger individual impact on risk. Their biological effects are concentrated in the brain and many of the same variants also increase the risk of other psychiatric disorders such as bipolar disorder, autism, and other neurodevelopmental conditions. Environmental risk factors include but are not limited to urban residence in childhood, migration, older paternal age at birth, cannabis use, childhood trauma, antenatal maternal infection, and perinatal hypoxia. Structural, functional, and neurochemical brain alterations implicate multiple regions and functional circuits. Dopamine D-2 receptor antagonists and partial agonists improve psychotic symptoms and reduce risk of relapse. Certain psychological and psychosocial interventions are beneficial. Early intervention can reduce treatment delay and improve outcomes. Schizophrenia is increasingly considered to be a heterogeneous syndrome and not a singular disease entity. There is no necessary or sufficient etiology, pathology, set of clinical features, or treatment that fully circumscribes this syndrome. A single, common pathophysiological pathway appears unlikely. The boundaries of schizophrenia remain fuzzy, suggesting the absence of a categorical fit and need to reconceptualize it as a broader, multi-dimensional and/or spectrum construct.

The Correlation Between Peripheral Blood Micro-Ribonucleic Acid Expression Level and Personality Disorder in Patients with Schizophrenia

Objective

Schizophrenia patients often have personality disorders; schizophrenia patients with personality disorders are more difficult to treat and have a worse prognosis. Early identification of this group of patients and early intervention can achieve better prognosis. Therefore, it is very important to explore effective biomarkers and early diagnosis for the prognosis of schizophrenia. The primary purpose of this paper is to explore the relationship between plasma miRNA expression level and personality disorder with schizophrenia.

Methods

Gene microarrays in miRNA files were employed, and the plasma of peripheral blood of 82 schizophrenic patients and 43 healthy control subjects were examined. Real-time reverse transcription polymerase chain reaction detection were performed to explore the results. Spearman correlation analysis was used to analyze the correlation between expression level of miRNAs and Personality Diagnosis Questionnaire-4 score.

Results

The results showed that miR-1273d, miR-1303, miR-3064-5p, miR-3131, miR-3687, miR-4428, miR-4725-3p, and miR-5096 were up-regulated in schizophrenic patients. Compared to healthy control subjects, the difference was statistically significant (P < .05). Schizophrenic patients with schizoid, paranoid, schizotypal, and obsessive compulsive traits had negative correlation with miR-1303, miR-3131, miR-4428, and miR-5096 expression level (r = -0.40 to -0.62, P < .05); there were no significant differences in the other miRNAs. Correlation with other personality traits was not significant (P > .05). The stepwise regression analysis indicated that miR-5096, miR-3131, and miR-1273d have a significant predictive effect on the schizoid trait (P < .01). MiR-4428 and miR-1303 had a significant predictive effect on the schizotypal trait (P < .01). MiR-5096, miR-4428, and miR-4725-3P had a significant predictive effect on the paranoid trait (P < .05). MiR-4428, miR-1303, and miR-5096 had a significant predictive effect on the obsessive compulsive trait (P < .05).

Conclusion

The expression levels of miR-1273d, miR-1303, miR-3064-5p, miR-3131, miR-3687, miR-4428, miR-4725-3p, and miR-5096 were up-regulated in the peripheral blood of patients with schizophrenia, and these miRNAs are expected to be diagnostic biomarkers for accurate diagnosis of schizophrenia. The expression levels of miR-1303, miR-3131, miR-1273d, miR-4428, miR-4725-3p, and miR-5096 have significant predictive effects on personality disorder in schizophrenia.

Association of daily-life functioning and obesity in individuals with schizophrenia and controls

Early weight gain following the diagnosis of schizophrenia (SCZ) has been associated with improved daily functioning. However, in the general population and in other psychiatric conditions such as bipolar disorder, increased body mass index (BMI) has been associated with worse functioning. The data on this association in chronic individuals with SCZ is still scarce. To address this gap in knowledge, our objective was to evaluate the association between BMI and psychosocial functioning in chronic outpatients with SCZ and in healthy individuals. Six-hundred individuals (n = 600), 312 with schizophrenia (SCZ) and 288 individuals with no personal or family history of severe mental illness (CTR), underwent weight, height and psychosocial functioning score (FAST) assessment. Linear regression models tested the association between FAST as dependent variable and BMI as independent variable, controlling for age, sex, use of clozapine and years of illness. In the CTR group, the highest BMI could predict a worse result in FAST, explaining about 22% of the variation found (Model: AdjR2 = 0.225 F(3,284) = 28.79 p < .001; BMI main effect: β = 0.509 t = 9.240 p < .001). In the SCZ group, there was no statistically significant association. Our findings corroborate the perception that increased BMI is associated with worse functioning status in the general population. In chronic SCZ, whatsoever, there is no association. Our findings suggest that patients with higher BMI in the SCZ group may compensate for the possible impairment of functionality due to increased body weight, through improved adherence and responsiveness to prescribed psychopharmacological treatment, leading to better control of psychiatric symptoms.

Efficacy of Serotonin and Dopamine Activity Modulators in the Treatment of Negative Symptoms in Schizophrenia: A Rapid Review

Schizophrenia is among the fifteen most disabling diseases worldwide. Negative symptoms (NS) are highly prevalent in schizophrenia, negatively affect the functional outcome of the disorder, and their treatment is difficult and rarely specifically investigated. Serotonin-dopamine activity modulators (SDAMs), of which aripiprazole, cariprazine, brexpiprazole, and lumateperone were approved for schizophrenia treatment, represent a possible therapy to reduce NS. The aim of this rapid review is to summarize the evidence on this topic to make it readily available for psychiatrists treating NS and for further research. We searched the PubMed database for original studies using SDAM, aripiprazole, cariprazine, brexpiprazole, lumateperone, schizophrenia, and NS as keywords. We included four mega-analyses, eight meta-analyses, two post hoc analyses, and 20 clinical trials. Aripiprazole, cariprazine, and brexpiprazole were more effective than placebo in reducing NS. Only six studies compared SDAMs with other classes of antipsychotics, demonstrating a superiority in the treatment of NS mainly for cariprazine. The lack of specific research and various methodological issues, related to the study population and the assessment of NS, may have led to these partial results. Here, we highlight the need to conduct new methodologically robust investigations with head-to-head treatment comparisons and long-term observational studies on homogeneous groups of patients evaluating persistent NS with first- and second-generation scales, namely the Brief Negative Symptom Scale and the Clinical Assessment Interview for Negative Symptoms. This rapid review can expand research on NS therapeutic strategies in schizophrenia, which is fundamental for the long-term improvement of patients’ quality of life.

Subjective Overview of Accelerated Aging in Schizophrenia

Schizophrenia, like many other human diseases, particularly neuropsychiatric diseases, shows evidence of accelerated brain aging. The molecular nature of the process of aging is unknown but several potential indicators have been used in research. The concept of accelerated aging in schizophrenia took hold in 2008 and its timing, pace, determinants and deterrents have been increasingly examined since. The present overview of the field is brief and selective, based on diverse studies, expert opinions and successive reviews. Current thinking is that the timing of age acceleration in schizophrenia can occur at different time periods of the lifespan in different individuals, and that antipsychotics may be preventive. The majority opinion is that the cognitive decline and premature death often seen in schizophrenia are, in principle, preventable.

Effects of socioeconomic status in cognition of people with schizophrenia: results from a Latin American collaboration network with 1175 subjects

BACKGROUND

Cognition heavily relies on social determinants and genetic background. Latin America comprises approximately 8% of the global population and faces unique challenges, many derived from specific demographic and socioeconomic variables, such as violence and inequality. While such factors have been described to influence mental health outcomes, no large-scale studies with Latin American population have been carried out. Therefore, we aim to describe the cognitive performance of a representative sample of Latin American individuals with schizophrenia and its relationship to clinical factors. Additionally, we aim to investigate how socioeconomic status (SES) relates to cognitive performance in patients and controls.

METHODS

We included 1175 participants from five Latin American countries (Argentina, Brazil, Chile, Colombia, and Mexico): 864 individuals with schizophrenia and 311 unaffected subjects. All participants were part of projects that included cognitive evaluation with MATRICS Consensus Cognitive Battery and clinical assessments.

RESULTS

Patients showed worse cognitive performance than controls across all domains. Age and diagnosis were independent predictors, indicating similar trajectories of cognitive aging for both patients and controls. The SES factors of education, parental education, and income were more related to cognition in patients than in controls. Cognition was also influenced by symptomatology.

CONCLUSIONS

Patients did not show evidence of accelerated cognitive aging; however, they were most impacted by a lower SES suggestive of deprived environment than controls. These findings highlight the vulnerability of cognitive capacity in individuals with psychosis in face of demographic and socioeconomic factors in low- and middle-income countries.

We are not ready to abandon the current schizophrenia construct, but should be prepared to do so

The current schizophrenia construct as delineated in the latest editions of the DSM and the ICD has some strengths, but also many weaknesses. It improved the reliability of the diagnosis, made communication among clinicians, users and families less ambiguous, is useful for education and training, and for reimbursement and insurance purposes. However, many serious weaknesses should be considered. The term "Schizophrenia" does not recognize the heterogeneity of the disorder and might nourish the belief that schizophrenia represents a unitary disease. In addition, there is no agreement on the existence and nature of a "core aspect" of the disorder. Stable dimensions, in particular negative symptoms and cognitive impairment, which are key determinants of functioning, are not de facto regarded as core aspects. Finally, the construct is associated to the notion of a poor outcome, to a high level of stigma and has acquired a derogatory connotation. We are not ready but should be prepared to abandon the current schizophrenia construct. Clinicians and researchers should be encouraged to complement the ICD/DSM diagnosis with an in-depth characterization of the individual clinical picture, along with other variables, such as family history, comorbidities, vulnerability factors and personal trajectory. The "Primary Psychoses" construct, together with improved cross-sectional and longitudinal phenotypes from representative population and patient cohorts, and the availability of artificial intelligence methods, could lead to a new and more precise taxonomy of psychotic disorders, and increase the probability of identifying meaningful biomarkers to improve prevention, diagnosis, prognosis, and treatment for people suffering from psychotic disorders.