Understanding the schizophrenia prodrome

Implications of altered pyramidal cell morphology on clinical symptoms of neurodevelopmental disorders

The prevalence of pyramidal cells (PCs) in the mammalian cerebral cortex underscore their value as they play a crucial role in various brain functions, ranging from cognition, sensory processing, to motor output. PC morphology significantly influences brain connectivity and plays a critical role in maintaining normal brain function. Pathological alterations to PC morphology are thought to contribute to the aetiology of neurodevelopmental disorders such as autism spectrum disorder (ASD) and schizophrenia. This review explores the relationship between abnormalities in PC morphology in key cortical areas and the clinical manifestations in schizophrenia and ASD. We focus largely on human postmortem studies and provide evidence that dendritic segment length, complexity and spine density are differentially affected in these disorders. These morphological alterations can lead to disruptions in cortical connectivity, potentially contributing to the cognitive and behavioural deficits observed in these disorders. Furthermore, we highlight the importance of investigating the functional and structural characteristics of PCs in these disorders to illuminate the underlying pathogenesis and stimulate further research in this area.

Current Findings and Potential Mechanisms of KarXT (Xanomeline-Trospium) in Schizophrenia Treatment

Standard schizophrenia treatment involves antipsychotic medications that target D2 dopamine receptors. However, these drugs have limitations in addressing all symptoms and can lead to adverse effects such as motor impairments, metabolic effects, sedation, sexual dysfunction, cognitive impairment, and tardive dyskinesia. Recently, KarXT has emerged as a novel drug for schizophrenia. KarXT combines xanomeline, a muscarinic receptor M1 and M4 agonist, with trospium, a nonselective antimuscarinic agent. Of note, xanomeline can readily cross blood-brain barrier (BBB) and, thus, enter into the brain, thereby stimulating muscarinic receptors (M1 and M4). By doing so, xanomeline has been shown to target negative symptoms and potentially improve positive symptoms. Trospium, on the other hand, is not able to cross BBB, thereby not affecting M1 and M4 receptors; instead, it acts as an antimuscarinic agent and, hence, diminishes peripheral activity of muscarinic receptors to minimize side effects probably stemming from xanomeline in other organs. Accordingly, ongoing clinical trials investigating KarXT's efficacy in schizophrenia have demonstrated positive outcomes, including significant improvements in the Positive and Negative Syndrome Scale (PANSS) total score and cognitive function compared with placebo. These findings emphasize the potential of KarXT as a promising treatment for schizophrenia, providing symptom relief while minimizing side effects associated with xanomeline monotherapy. Despite such promising evidence, further research is needed to confirm the efficacy, safety, and tolerability of KarXT in managing schizophrenia. This review article explores the current findings and potential mechanisms of KarXT in the treatment of schizophrenia.

Polygenic risk of social isolation behavior and its influence on psychopathology and personality

Social isolation has been linked to a range of psychiatric issues, but the behavioral component that drives it is not well understood. Here, a genome-wide associations study (GWAS) was carried out to identify genetic variants that contribute specifically to social isolation behavior (SIB) in up to 449,609 participants from the UK Biobank. 17 loci were identified at genome-wide significance, contributing to a 4% SNP-based heritability estimate. Using the SIB GWAS, polygenic risk scores (PRS) were derived in ALSPAC, an independent, developmental cohort, and used to test for association with self-reported friendship scores, comprising items related to friendship quality and quantity, at age 12 and 18 to determine whether genetic predisposition manifests during childhood development. At age 18, friendship scores were associated with the SIB PRS, demonstrating that the genetic factors can predict related social traits in late adolescence. Linkage disequilibrium (LD) score correlation using the SIB GWAS demonstrated genetic correlations with autism spectrum disorder (ASD), schizophrenia, major depressive disorder (MDD), educational attainment, extraversion, and loneliness. However, no evidence of causality was found using a conservative Mendelian randomization approach between SIB and any of the traits in either direction. Genomic Structural Equation Modeling (SEM) revealed a common factor contributing to SIB, neuroticism, loneliness, MDD, and ASD, weakly correlated with a second common factor that contributes to psychiatric and psychotic traits. Our results show that SIB contributes a small heritable component, which is associated genetically with other social traits such as friendship as well as psychiatric disorders.

Lisdexamfetamine-Induced Psychosis in a Patient With a Neurodevelopmental Disorder

Individuals diagnosed with autism spectrum disorder (ASD) often experience a higher occurrence of comorbid attention deficit hyperactivity disorder (ADHD). Stimulant medications are frequently prescribed to manage ADHD. In rare instances, the use of stimulant medications has been linked to the development of psychotic symptoms. This is a case of a 13-year-old male diagnosed with ASD and comorbid ADHD, anxiety, and depression, who presented with an abrupt onset of psychosis, which manifested about a week after the initiation of lisdexamfetamine. The psychotic symptoms subsided upon discontinuation of lisdexamfetamine; however, there was a re-emergence of severe ADHD symptoms that proved resistant to non-stimulant medications. The patient experienced significant improvement without any recurrence of psychosis after being prescribed extended-release methylphenidate. Notably, there are no established clinical guidelines to assist in selecting one stimulant over another in the treatment of ADHD comorbid with ASD. The authors recommend considering the methylphenidate class of stimulants as a first-line treatment for ADHD in individuals with ASD, citing better tolerability compared to amphetamines.

Psychedelics action and schizophrenia

Psychedelics are compounds acting by serotonin 5-hydroxytryptamine (5-HT)2A receptor activation and induce several behavioral responses. They are of special interest because of their positive effects on neuropsychiatric disorders (depression and posttraumatic stress disorder). However, several findings revealed that some psychedelic actions are similar to symptoms observed in schizophrenia (psychosis, sensorimotor gating impairments, attention, and working memory deficits) which might limit their clinical applications. Psychedelics activate some neurotransmitters, i.e., serotonergic, and glutamatergic, that are also impaired in schizophrenia. Therefore, the neurobiological background of psychedelics and schizophrenia is partially similar. Another important aspect to discuss is the perspective of using psychedelics in schizophrenia therapy. Postmortem studies showed a loss of synapses in schizophrenia, and the positive effects of psychedelics on neuroplasticity (synaptogenesis, neurogenesis, and neuritogenesis) might be essential in the context of schizophrenia therapy. However, because of psychedelics' psychotic action, the recommended doses of psychedelics in schizophrenia treatment are not established, and subpsychedelic dosing or microdosing are considered. Exploratory studies are needed to determine the tolerability of treatment and appropriate dosing regimen. Another therapeutic option is using non-hallucinogenic psychedelic analogs that also induce neuroplastic outcomes but do not have psychotogenic effects. Further preclinical and clinical studies are needed to recognize the potential effectiveness of 5-HT2A agonists in schizophrenia therapy.

Gamma oscillations provide insights into cortical circuit development

Rhythmic coordination in gamma oscillations provides temporal structure to neuronal activity. Gamma oscillations are commonly observed in the mammalian cerebral cortex, are altered early on in several neuropsychiatric disorders, and provide insights into the development of underlying cortical networks. However, a lack of knowledge on the developmental trajectory of gamma oscillations prevented the combination of findings from the immature and the adult brain. This review is intended to provide an overview on the development of cortical gamma oscillations, the maturation of the underlying network, and the implications for cortical function and dysfunction. The majority of information is drawn from work in rodents with particular emphasis on the prefrontal cortex, the developmental trajectory of gamma oscillations, and potential implications for neuropsychiatric disorders. Current evidence supports the idea that fast oscillations during development are indeed an immature form of adult gamma oscillations and can help us understand the pathology of neuropsychiatric disorders.

Polygenic risk of Social-isolation and its influence on social behavior, psychosis, depression and autism spectrum disorder

Social-isolation has been linked to a range of psychiatric issues, but the behavioral component that drives it is not well understood. Here, a GWAS is carried out to identify genetic variants which contribute to Social-isolation behaviors in up to 449,609 participants from the UK Biobank. 17 loci were identified at genome-wide significance, contributing to a 4% SNP heritability estimate. Using the Social-isolation GWAS, polygenic risk scores (PRS) were derived in ALSPAC, an independent, developmental cohort, and used to test for association with friendship quality. At age 18, friendship scores were associated with the Social-isolation PRS, demonstrating that the genetic factors are able to predict related social traits. LD score regression using the GWAS demonstrated genetic correlation with autism spectrum disorder, schizophrenia, and major depressive disorder. However, no evidence of causality was found using a conservative Mendelian randomization approach other than that of autism spectrum disorder on Social-isolation. Our results show that Social-isolation has a small heritable component which may drive those behaviors which is associated genetically with other social traits such as friendship satisfaction as well as psychiatric disorders.

[Juvenile depression as at-risk state for psychotic disorders]

OBJECTIVE

To establish the risk of psychotic disorders in juvenile depression and to study the role of negative symptoms in its formation.

MATERIAL AND METHODS

Seventy-four in-patients (19.6±2.3 years old), who were hospitalized for the first time in the clinic for a depressive episode, were examined. Psychometric scales HDRS, SOPS, SANS were used. The risk of manifestation of psychotic disorders was established in the presence of attenuated positive symptoms (APS) with values of at least one of the points P1, P2, P3 and P4 of the corresponding SOPS subscale more or equal to 3. The overall risk of schizophrenia spectrum disorders was established in the presence of attenuated negative symptoms (ANS) with values of at least one of the points H1-H6 of the negative SOPS subscale is more than or equal to 5. Statistical analysis was carried out using the Statistica 12 program.

RESULTS

During the psychometric assessment of patients at admission, four groups were identified based on the presence of APS and ANS: group 1 (APS+ANS), group 2 (APS), group 3 (ANS) and a comparison group without APS/ANS. It was found that the presence of APS and ANS in the structure of depression increased its severity (U=109.0; p=0.009). Assessment of the ANS severity on the negative subscale of SOPS and on the SANS demonstrated quantitative differences with the highest representation of negative symptoms in the corresponding groups (APS+ANS and ANS) with significant differences in total scores in the comparison group (U=93.0; p=0.004 and U=85.0; p=0.002). When studying the structure of negative symptoms according to the SANS subscales, patients with APS differed in a lower degree of severity of negative symptoms only according to the «Avolition-Apathy» subscale (U=141.5; p=0.028). Patients from the comparison group, despite significant differences in other psychopathological symptoms, showed lower values only for the SANS subscales «Affective flattening» (U=112.0; p=0.02) and, to a greater extent, «Avolition-Apathy» (U=84.0; p=0.002).

CONCLUSION

Based on the presence of prodromal symptoms in the structure of juvenile depression and their dynamics during therapy, one can assume not only a different degree of risk of endogenous psychoses, but also their nosological affiliation.

The prevalence of physical multimorbidity among people with non-affective psychotic disorders 10 years after first diagnosis: a matched retrospective cohort study

AIMS

The higher prevalence of chronic physical health conditions among people with psychotic disorders may result in a reduced life expectancy as compared to the general population. More research is needed on the risk of multiple co-occurring chronic health conditions, known as multimorbidity, for people with psychotic disorders.

METHODS

We conducted a matched retrospective cohort study to quantify the prevalence of multimorbidity and associated factors among people with psychotic disorders over the 10-year period following first diagnosis, relative to those without psychosis. Data from an early psychosis intervention program in London, Canada were linked to population-based health administrative data to identify patients with first-episode psychosis (n = 439), and a comparison group from the general population (n = 1759) matched on age, sex, and postal code. We followed the cohort for 10 years to ascertain the prevalence of multimorbidity. We compared people with and without psychosis using modified Poisson regression models, and explored risk factors for multimorbidity among those with psychotic disorders.

RESULTS

People with psychotic disorders may have a 26% higher prevalence of multimorbidity 10 years following first diagnosis, although our findings include the possibility of a null effect (PR = 1.26, 95% CI 0.96-1.66). People with psychosis living in areas with the highest levels of material deprivation had a threefold higher prevalence of multimorbidity as compared to those in the lowest areas of material deprivation (PR = 3.09, 95% CI 1.21-7.90).

CONCLUSION

Multimorbidity is prevalent among those with psychosis, and assessment for chronic health conditions should be integrated into clinical care for younger populations with psychotic illness.

Combined pattern of childhood psycho-behavioral characteristics in patients with schizophrenia: a retrospective study in Japan

BACKGROUND

Although epidemiological and genetic studies have provided scientific evidence that places schizophrenia into the framework of early neurodevelopmental disorders, the psycho-behavioral characteristics of children that later go on to develop schizophrenia have not been sufficiently clarified. This study aimed to retrospectively identify characteristics specific to patients with schizophrenia during childhood via their guardians' reporting of these characteristics.

METHODS

Participants included 54 outpatients with schizophrenia in their twenties who fulfilled DSM-IV-TR criteria. Additionally, 192 normal healthy subjects participated as sex- and age-matched controls. The guardians of all participants were recruited to rate participants' childhood characteristics from 6 to 8 years of age on a modified version of the Child Behavior Checklist (CBCL), which was used as a retrospective assessment questionnaire. Using t-tests, logistic regression, and Receiver Operating Characteristic (ROC) curve analysis, we estimated the psycho-behavioral characteristics specific to schizophrenia during childhood. Using the obtained logistic regression model, we prototyped a risk-predicting algorithm based on the CBCL scores.

RESULTS

Among the eight CBCL subscale t-scores, "withdrawn" (p = 0.002), "thought problems" (p = 0.001), and "lack of aggressive behavior" (p = 0.002) were each significantly associated with the later diagnosis of schizophrenia, although none of these mean scores were in the clinical range at the time of childhood. The algorithm of the logistic regression model, based on eight CBCL subscales, had an area under the ROC curve of 82.8% (95% CI: 76-89%), which indicated that this algorithm's prediction of late development of schizophrenia has moderate accuracy.

CONCLUSIONS

The results suggest that according to guardian reports, participants showed psycho-behavioral characteristics during childhood, different to those of healthy controls, which could be predictive of the later development of schizophrenia. Our newly developed algorithm is available to use in future studies to further test its validity.

Secondary Prevention of Depressive Prodrome in Adolescents: Before and After Attending a Jogging Program on Campus

The adolescent depressive prodrome has been conceptualized as an early integrated sign of depressive symptoms, which may develop to a first episode of depression or return to normal for the adolescents. In this study, depressive prodrome presented the early self-rated depressive symptoms for the sample participants. By referring to the Kutcher Adolescent Depression Scale and the psychometric characteristics of the Adolescent Depression Scale (ADR), we proposed a self-rated questionnaire to assess the severity of the depressive symptoms in adolescents before and after attending the jogging program on a high school campus in Taiwan. With the parental co-signature and self-signed informed consent form, 284 high school students under the average age of 15 years, participated in this study in March 2019. Through the software of IBMSPSS 25, we used a binary logistic model, principal component analysis (PCA), multiple-dimensional analysis, and receiver operating characteristic curve (ROC) to analyze the severity of the depressive prodrome via the threshold severity score (SC) and false positive rate (FPR). Findings revealed that attending the 15-week jogging program (3 times a week, 45 min each) on campus can change the severity status and reduce the prevalence of moderate-severe depressive prodrome by 26%. The two-dimensional approach identified three symptoms, which were the crying spell, loss of pleasure doing daily activities, and feeling the decline in memory. They kept being invariant symptoms during the course of depressive prodrome assessment for sample participants. In this study, the campus jogging program appeared to be able to affect the FPR of the measure of depressive prodrome. Compared with the subthreshold depression, the depressive prodrome emphasized the assessment from the view of the secondary prevention by representing the change from a person's premorbid functioning up until the first onset of depression or returning to normal. However, the subthreshold depression is a form of minor depression according to DSM-5 criteria varying on the number of symptoms and duration required, highly prevalent in the concern of primary care.

Polygenic risk score as clinical utility in psychiatry: a clinical viewpoint

Genome-wide association studies (GWASs) have detected many susceptible variants for common diseases, including psychiatric disorders. However, because of the small effect size of each variant, clinical utility that aims for risk prediction and/or diagnostic assistance based on the individual "variants" is difficult to use. Therefore, to improve the statistical power, polygenic risk score (PRS) has been established and applied in the GWAS as a robust analytic tool. Although PRS has potential predictive ability, because of its current "insufficient" discriminative power at the individual level for clinical use, it remains limited solely in the research area, specifically in the psychiatric field. For a better understanding of the PRS, in this review, we (1) introduce the clinical features of psychiatric disorders, (2) summarize the recent GWAS/PRS findings in the psychiatric disorders, (3) evaluate the problems of PRS, and (4) propose its possible utility to apply PRS into the psychiatric clinical setting.

Understanding anhedonia: a qualitative study exploring loss of interest and pleasure in adolescent depression

Anhedonia (or loss of interest and pleasure) is a core symptom of depression and may predict poor treatment outcome. However, little is known about the subjective experience of anhedonia, and it is rarely targeted in psychological treatment for depression. The aim of this study is to examine how young people experience anhedonia in the context of depression. Semi-structured interviews were conducted with 34 adolescents with a primary diagnosis of depression (N = 12) or elevated depressive symptoms (N = 22). Thematic analysis was used to identify important aspects of adolescents' experiences. Four main themes were identified: (1) experiencing a loss of joy and a flattening of emotion; (2) struggling with motivation and active engagement; (3) losing a sense of connection and belonging; and (4) questioning sense of self, purpose, and the bigger picture. The results challenge the framing of anhedonia as simply the loss of interest and pleasure. Adolescents reported a range of experiences that mapped closely onto the cluster of negative symptoms associated with schizophrenia and were similar to the sense of 'apathy' characteristic in Parkinson's disease. This highlights the potential benefit of taking a trans-diagnostic approach to understanding and treating reward deficits associated with mental health problems.