Sex/gender differences in the brain and cognition in schizophrenia

Modeling the interplay of age at onset and sex on cognition in Schizophrenia

Cognition remains one of the most critical features of the schizophrenia. A wide range of factors has been associated to neurocognition and, among these, sex and age of onset are two of the most consistently reported to influence the functional and cognitive outcome. This work aims to evaluate the effects of sex and age of onset and their interaction on cognition in 419 subjects with schizophrenia. Analyses of variance and analyses of covariance were performed to evaluate the effect of sex and age at onset on cognition. To model the possible interaction sex-onset on cognition, a separate slope regression analysis was performed. Analyses of variance showed significant differences between sexes for age and age at onset, both significantly higher among females, as well as for Executive Functions, with higher performance among males. When compared according to age at onset, late-onset patients performed better than both early- and intermediate-onset ones in Verbal Memory subtest, with a significant effect of length of illness. Moreover, early-onset patients showed a significantly lower IQ compared to both intermediate and late-onset ones, with no significant effect of length of illness. Finally, the separate slope regression revealed a significant interaction between sex and age at onset, with early-onset being associated to a worse global cognition only among male patients. Our finding of a significant sex-onset interaction effect on neurocognition sheds new light on the complex issue of cognitive heterogeneity in schizophrenia. Our data may help towards the development of personalized programs for preventive and rehabilitative purposes.

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.

Sexual dimorphism in the relationship between Forkhead-Box P2 and BMI with cognitive deficits in schizophrenia

FOXP2, cognitive deficits, and schizophrenia are associated with neurodegenerative pathophyisiology. Mounting evidence suggests that body mass index (BMI) and FOXP2 may contribute to cognitive deficits in schizophrenia. However, the sex difference in the contribution of FOXP2 and BMI, as well as their potential interaction with cognitive deficits in schizophrenia, have not been investigated. A total of 867 schizophrenia patients and 402 controls were recruited. Cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The polymorphism rs10447760 of the FOXP2 gene was genotyped. Male schizophrenia patients had superior language performance compared to female patients (F = 17.83; pBonferroni < 0.0001). BMI was positively associated with language scores in male patients with schizophrenia (ß = 0.60, t = 3.30, p = 0.001), as well as in patients with schizophrenia who carried the FOXP2 rs10447760 CC genotype (ß = 0.53, t = 3.16, p = 0.002). Interestingly, this association was only found in male patients with schizophrenia who also carried the FOXP2 rs10447760 CC genotype (ß = 0.63, t = 3.44, p = 0.001). Our study reveals a sex difference in the language deficits of schizophrenia patients and shows sexual dimorphism in the contribution of FOXP2, BMI, and their interaction to cognitive deficits in patients with schizophrenia.

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.

Prevalence, profile and associations of cognitive impairment in Ugandan first-episode psychosis patients

Introduction

The MATRICS consensus cognitive battery (MCCB) is the gold standard for neuropsychological assessment in psychotic disorders but is rarely used in low resource settings. This study used the MCCB to determine the prevalence, profile and associations of various exposures with cognitive impairment in Ugandan first-episode psychosis patients.

Methods

Patients and matched healthy controls were recruited at Butabika Hospital in Uganda. Clinical variables were first collated, and after the resolution of psychotic symptoms, a neuropsychological assessment of seven cognitive domains was performed using the MCCB. Cognitive impairment was defined as two standard deviations (SD) below the mean in one domain or 1SD below the mean in two domains. Descriptive statistics determined the prevalence and profile of impairment while regression models determined the association between various exposures with cognitive scores while controlling for age, sex and education.

Results

Neuropsychological assessment with the MCCB found the burden of cognitive impairment in first-episode psychosis patients five times that of healthy controls. The visual learning and memory domain was most impaired in first-episode psychosis patients, while it was the working memory domain for the healthy controls. Increased age was associated with impairment in the domains of the speed of processing (p < 0.001) and visual learning and memory (p = 0.001). Cassava-rich diets and previous alternative and complementary therapy use were negatively associated with impairment in the visual learning (p = 0.04) and attention/vigilance domains (p = 0.012), respectively. There were no significant associations between sex, history of childhood trauma, or illness severity with any cognitive domain.

Conclusion

A significant burden of cognitive impairment in Ugandan first-episode psychosis patients is consistent with prior data from other contexts. However, the profile of and risk factors for impairment differ from that described in such work. Therefore, interventions to reduce cognitive impairment in FEP patients specific to this setting, including dietary modifications, are required.

Factors Influencing Post-Stroke Cognitive Impairment in Patients with Type 2 Diabetes Mellitus

Objective

Type 2 diabetes mellitus (T2DM) and ischemic stroke, which are common diseases among older people, are closely related to cognitive impairment. This study aims to investigate the influencing factors of post-stroke cognitive impairment (PSCI) in patients with T2DM.

Methods

We enrolled 161 patients with T2DM who experienced acute ischemic stroke and were hospitalized in the Department of Neurology, Jinan Central Hospital, Shandong, China. Cognitive function was evaluated with the Montreal Cognitive Assessment scale. According to the results, patients were divided into three groups-the cognitively normal group, mild cognitive impairment group, and severe cognitive impairment group. We analyzed general demographic data, laboratory information, imaging data, the results of neuropsychological evaluation, and clinical features as well as influencing factors of PSCI in these patients and established a prediction model.

Results

The three groups of patients were significantly different in terms of age, education level, course of diabetes mellitus (DM), recurrent cerebral infarction (RCI), and other factors. RCI, course of DM, and glycated hemoglobin (HbA1c) were independent risk factors of PSCI in patients with T2DM, with odds ratio (95% confidence interval): 7.17 (2.09, 30.37), 5.39 (2.40, 14.59), and 3.89 (1.66, 10.04), respectively, whereas female, senior high school, serum albumin were protective factors: 0.28 (0.07, 0.95), 0.05 (0.01, 0.21), 0.20 (0.08, 0.42), respectively. Furthermore, we constructed a prediction model using sex, age, education level, RCI, DM course, HbA1c and serum albumin and obtained a receiver operating characteristic (ROC) curve. The area under the ROC curve is 0.966, suggesting the significant association of these influencing factors with PSCI in patients with T2DM.

Conclusion

In this study, the occurrence of PSCI in patients with T2DM was related to RCI, course of DM, and HbA1c, among other factors. Attention to influencing factors is needed in these patients for early diagnosis and timely intervention of cognitive impairment.

Sex Differences in Social Cognition and Association of Social Cognition and Neurocognition in Early Course Schizophrenia

Background

Both impairment and sex differences in social cognition and neurocognition have been documented in schizophrenia. However, whether sex differences exist in the association between social cognition and neurocognition are not known. We aimed to investigate the contribution of areas of neurocognition to theory of mind (ToM) and hostility bias, representing social cognition, according to sex in early course schizophrenia.

Methods

In this cross-sectional study, we assessed neurocognition using the Japanese version of the Brief Assessment of Cognition in Schizophrenia (BACS) and assessed the ToM and hostility bias subdomains of social cognition using the Social Cognition Screening Questionnaire (SCSQ) in 131 participants (65 female, 66 male) diagnosed with schizophrenia within 5 years of onset. Sex differences were analyzed using t-tests. The associations of neurocognitive subdomains with ToM and hostility bias according to sex were analyzed using multiple regression analysis. Results were adjusted by age, estimated premorbid intelligence quotient, and symptomatology.

Results

No sex differences were found in ToM (p = 0.071) or hostility bias (p = 0.057). Higher verbal fluency was significantly associated with higher ToM in females (p < 0.01), whereas higher executive function was significantly associated with higher ToM in males (p < 0.05). Higher verbal fluency was significantly associated with lower hostility bias in females (p < 0.05), whereas neurocognition and hostility bias were not significantly associated in males.

Conclusion

The results suggest that neurocognition associated with social cognition differ according to sex. These differences should be considered for more effective treatment of social cognition.

Detection of advanced brain aging in schizophrenia and its structural underpinning by using normative brain age metrics

Conceptualizing mental disorders as deviations from normative functioning provides a statistical perspective for understanding the individual heterogeneity underlying psychiatric disorders. To broaden the understanding of the idiosyncrasy of brain aging in schizophrenia, we introduced an imaging-derived brain age paradigm combined with normative modeling as novel brain age metrics. We constructed brain age models based on GM, WM, and their combination (multimodality) features of 482 normal participants. The normalized predicted age difference (nPAD) was estimated in 147 individuals with schizophrenia and their 130 demographically matched controls through normative models of brain age metrics and compared between the groups. Regression analyses were also performed to investigate the associations of nPAD with illness duration, onset age, symptom severity, and intelligence quotient. Finally, regional contributions to advanced brain aging in schizophrenia were investigated. The results showed that the individuals exhibited significantly higher nPAD (P < 0.001), indicating advanced normative brain age than the normal controls in GM, WM, and multimodality models. The nPAD measure based on WM was positively associated with the negative symptom score (P = 0.009), and negatively associated with the intelligence quotient (P = 0.039) and onset age (P = 0.006). The imaging features that contributed to nPAD mostly involved the prefrontal, temporal, and parietal lobes, especially the precuneus and uncinate fasciculus. This study demonstrates that normative brain age metrics could detect advanced brain aging and associated clinical and neuroanatomical features in schizophrenia. The proposed nPAD measures may be useful to investigate aberrant brain aging in mental disorders and their brain-phenotype relationships.

Polygenic Risk for Schizophrenia Has Sex-Specific Effects on Brain Activity during Memory Processing in Healthy Individuals

Genetic risk for schizophrenia has a negative impact on memory and other cognitive abilities in unaffected individuals, and it was recently shown that this effect is specific to males. Using functional MRI, we investigated the effect of a polygenic risk score (PRS) for schizophrenia on brain activation during working memory and episodic memory in 351 unaffected participants (167 males and 184 females, 25–95 years), and specifically tested if any effect of PRS on brain activation is sex-specific. Schizophrenia PRS was significantly associated with decreased brain activation in the left dorsolateral prefrontal cortex (DLPFC) during working-memory manipulation and in the bilateral superior parietal lobule (SPL) during episodic-memory encoding and retrieval. A significant interaction effect between sex and PRS was seen in the bilateral SPL during episodic-memory encoding and retrieval, and sex-stratified analyses showed that the effect of PRS on SPL activation was male-specific. These results confirm previous findings of DLPFC inefficiency in schizophrenia, and highlight the SPL as another important genetic intermediate phenotype of the disease. The observed sex differences suggest that the previously shown male-specific effect of schizophrenia PRS on cognition translates into an additional corresponding effect on brain functioning.

Schizophrenia-like endurable behavioral and neuroadaptive changes induced by ketamine administration involve Angiotensin II AT1 receptor

Schizophrenia is a chronic disease affecting 1% worldwide population, of which 30% are refractory to the available treatments: thus, searching for new pharmacological targets is imperative. The acute and repeated ketamine administration are validated preclinical models that recreate the behavioral and neurochemical features of this pathology, including the parvalbumin-expressing interneurons dysfunction. Angiotensin II, through AT₁ receptors (AT₁-R), modulates the dopaminergic and GABAergic neurotransmission. We evaluated the AT₁-R role in the long-term neuronal activation and behavioral alterations induced by repeated ketamine administration. Adult male Wistar rats received AT₁-R antagonist candesartan/vehicle (days 1-10) and ketamine/saline (days 6-10). After 14 days of drug-free, neuronal activation and behavioral analysis were performed. Locomotor activity, social interaction and novel object recognition tests were assessed at basal conditions or after ketamine challenge. Immunostaining for c-Fos, GAD67 and parvalbumin were assessed after ketamine challenge in cingulate, insular, piriform, perirhinal, and entorhinal cortices, striatum, and hippocampus. Additionally, to evaluate the AT₁-R involvement in acute ketamine psychotomimetic effects, the same behavioral tests were performed after 6 days of daily-candesartan and a single-ketamine administration. We found that ketamine-induced long-lasting schizophrenia-like behavioral alterations, and regional-dependent neuronal activation changes, involving the GABAergic neurotransmission system and the parvalbumin-expressing interneurons, were AT₁-R-dependent. The AT₁-R were not involved in the acute ketamine psychotomimetic effects. These results add new evidence to the wide spectrum of action of ketamine and strengthen the AT₁-R involvement in endurable alterations induced by psychostimulants administration, previously proposed by our group, as well as their preponderant role in the development of psychiatric pathologies.

The Sexual Dimorphic Synapse: From Spine Density to Molecular Composition

A synaptic sexual dimorphism is relevant in the context of multiple neurodevelopmental, neurodegenerative, and neuropsychiatric disorders. Many of these disorders show a different prevalence and progression in woman and man. A similar variance is also present in corresponding animal models. To understand and characterize this dimorphism in pathologies it is important to first understand sex differences in unaffected individuals. Therefore, sexual differences have been studied since 1788, first focusing on brain weight, size, and volume. But as these measures are not directly related to brain function, the investigation of sexual dimorphism also expanded to other organizational levels of the brain. This review is focused on sexual dimorphism at the synaptic level, as these specialized structures are the smallest functional units of the brain, determining cell communication, connectivity, and plasticity. Multiple differences between males and females can be found on the levels of spine density, synaptic morphology, and molecular synapse composition. These differences support the importance of sex-disaggregated data. The specificity of changes to a particular brain region or circuit might support the idea of a mosaic brain, in which each tile individually lies on a continuum from masculinization to feminization. Moreover, synapses can be seen as the smallest tiles of the mosaic determining the classification of larger areas.

Sex difference in association between insomnia and cognitive impairment in patients with chronic schizophrenia

OBJECTIVE

Sex differences in schizophrenia have been noted across domains such as sleep and cognitive function； however, how they interact remains unclear. This study aimed to explore sex differences in the relationship between insomnia and cognitive function in patients with chronic schizophrenia.

METHODS

718 schizophrenia patients (480 males and 238 females) and 397 healthy controls were recruited. Insomnia was collected by a questionnaire. Insomnia severity index (ISI) was used to evaluate the severity of insomnia. The clinical symptoms and cognition were assessed with the Positive and Negative Syndrome Scale (PANSS) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), respectively.

RESULTS

Schizophrenia patients showed significantly lower scores compared to healthy controls on the RBANS total score and four indexes (all p < 0.05). Male patients had a lower rate of insomnia, higher scores on the RBANS visuospatial/constructional, language, and total score than female patients (all P < 0.05). Insomnia patients had lower RBANS immediate memory, language, and total scores than non-insomnia patients, and the results only appeared in female patients (all P < 0.05). In addition, there were significant negative correlations between ISI and RBANS language and delayed memory in male patients, while ISI was significantly negatively correlated with RBANS immediate memory in female patients (all P < 0.05).

CONCLUSION

Our findings suggest that there are sex differences in insomnia, cognitive performance, and their association in patients with chronic schizophrenia. These sex differences may have important potential clinical significance for the identification, evaluation, and treatment of insomnia in patients with chronic schizophrenia.

Detection of functional and structural brain alterations in female schizophrenia using elastic net logistic regression

Neuroimaging technique is a powerful tool to characterize the abnormality of brain networks in schizophrenia. However, the neurophysiological substrate of schizophrenia is still unclear. Here we investigated the patterns of brain functional and structural changes in female patients with schizophrenia using elastic net logistic regression analysis of resting-state functional magnetic resonance imaging data. Data from 52 participants (25 female schizophrenia patients and 27 healthy controls) were obtained. Using an elastic net penalty, the brain regions most relevant to schizophrenia pathology were defined in the models using the amplitude of low-frequency fluctuations (ALFF) and gray matter, respectively. The receiver operating characteristic analysis showed reliable classification accuracy with 85.7% in ALFF analysis, and 77.1% in gray matter analysis. Notably, our results showed eight common regions between the ALFF and gray matter analyses, including the Frontal-Inf-Orb-R, Rolandic-Oper-R, Olfactory-R, Angular-L, Precuneus-L, Precuenus-R, Heschl-L, and Temporal-Pole-Mid-R. In addition, the severity of symptoms was found positively associated with the ALFF within the Rolandic-Oper-R and Frontal-Inf-Orb-R. Our findings indicated that elastic net logistic regression could be a useful tool to identify the characteristics of schizophrenia -related brain deterioration, which provides novel insights into schizophrenia diagnosis and prediction.

Acoustic and Facial Features From Clinical Interviews for Machine Learning-Based Psychiatric Diagnosis: Algorithm Development

BACKGROUND

In contrast to all other areas of medicine, psychiatry is still nearly entirely reliant on subjective assessments such as patient self-report and clinical observation. The lack of objective information on which to base clinical decisions can contribute to reduced quality of care. Behavioral health clinicians need objective and reliable patient data to support effective targeted interventions.

OBJECTIVE

We aimed to investigate whether reliable inferences-psychiatric signs, symptoms, and diagnoses-can be extracted from audiovisual patterns in recorded evaluation interviews of participants with schizophrenia spectrum disorders and bipolar disorder.

METHODS

We obtained audiovisual data from 89 participants (mean age 25.3 years; male: 48/89, 53.9%; female: 41/89, 46.1%): individuals with schizophrenia spectrum disorders (n=41), individuals with bipolar disorder (n=21), and healthy volunteers (n=27). We developed machine learning models based on acoustic and facial movement features extracted from participant interviews to predict diagnoses and detect clinician-coded neuropsychiatric symptoms, and we assessed model performance using area under the receiver operating characteristic curve (AUROC) in 5-fold cross-validation.

RESULTS

The model successfully differentiated between schizophrenia spectrum disorders and bipolar disorder (AUROC 0.73) when aggregating face and voice features. Facial action units including cheek-raising muscle (AUROC 0.64) and chin-raising muscle (AUROC 0.74) provided the strongest signal for men. Vocal features, such as energy in the frequency band 1 to 4 kHz (AUROC 0.80) and spectral harmonicity (AUROC 0.78), provided the strongest signal for women. Lip corner-pulling muscle signal discriminated between diagnoses for both men (AUROC 0.61) and women (AUROC 0.62). Several psychiatric signs and symptoms were successfully inferred: blunted affect (AUROC 0.81), avolition (AUROC 0.72), lack of vocal inflection (AUROC 0.71), asociality (AUROC 0.63), and worthlessness (AUROC 0.61).

CONCLUSIONS

This study represents advancement in efforts to capitalize on digital data to improve diagnostic assessment and supports the development of a new generation of innovative clinical tools by employing acoustic and facial data analysis.

Metabolic Sex Dimorphism of the Brain at the Gene, Cell, and Tissue Level

The palpable observation in the sex bias of disease prevalence in the CNS has fascinated scientists for several generations. Brain sex dimorphism has been visualized by imaging and analytical tools at the tissue, cellular, and molecular levels. Recent work highlighted the specificity of such sex bias in the brain and its subregions, offering a unique lens through which disease pathogenesis can be investigated. The brain is the largest consumer of energy in the body and provides a unique metabolic environment for diverse lineages of cells. Immune cells are increasingly recognized as an integral part of brain physiology, and their function depends on metabolic homeostasis. This review focuses on metabolic sex dimorphism in brain tissue, resident, and infiltrating immune cells. In this context, we highlight the relevance of recent advances in metabolomics and RNA sequencing technologies at the single cell resolution and the development of novel computational approaches.

Influence of clinical and neurocognitive factors in psychosocial functioning after a first episode non-affective psychosis: Differences between males and females

BACKGROUND

Deficits in psychosocial functioning are present in the early stages of psychosis. Several factors, such as premorbid adjustment, neurocognitive performance, and cognitive reserve (CR), potentially influence functionality. Sex differences are observed in individuals with psychosis in multiple domains. Nonetheless, few studies have explored the predictive factors of poor functioning according to sex in first-episode psychosis (FEP). This study aimed to explore sex differences, examine changes, and identify predictors of functioning according to sex after onset.

MATERIALS AND METHODS

The initial sample comprised 588 individuals. However, only adults with non-affective FEP (n = 247, 161 males and 86 females) and healthy controls (n = 224, 142 males and 82 females) were included. A comprehensive assessment including functional, neuropsychological, and clinical scales was performed at baseline and at 2-year follow-up. A linear regression model was used to determine the predictors of functioning at 2-year follow-up.

RESULTS

FEP improved their functionality at follow-up (67.4% of both males and females). In males, longer duration of untreated psychosis (β = 0.328, p = 0.003) and worse premorbid adjustment (β = 0.256, p = 0.023) were associated with impaired functioning at 2-year follow-up, while in females processing speed (β = 0.403, p = 0.003), executive function (β = 0.299, p = 0.020) and CR (β = -0.307, p = 0.012) were significantly associated with functioning.

CONCLUSION

Our data indicate that predictors of functioning at 2-year follow-up in the FEP group differ according to sex. Therefore, treatment and preventative efforts may be adjusted taking sex into account. Males may benefit from functional remediation at early stages. Conversely, in females, early interventions centered on CR enhancement and cognitive rehabilitation may be recommended.

Sex differences in symptom severity, cognition and psychosocial functioning among individuals with at-risk mental state for psychosis

AIM

Sex differences are well documented in schizophrenia, but have been much less studied in at-risk mental state (ARMS) for psychosis. We aimed to examine sex differences in symptomatology, cognition, social and role functioning in individuals with ARMS, with specific focus on clarifying relationships between sex, negative symptoms and functioning.

METHODS

One hundred and seventy-seven Chinese participants aged 15-40 years with ARMS were recruited from a specialized early intervention service in Hong Kong. ARMS status was verified by Comprehensive Assessment of At-Risk Mental State. Assessments encompassing symptom profiles, a brief battery of cognitive tests and social and role functioning were conducted. Brief Negative Symptom Scale was adapted to measure negative symptoms at the level of five core domains.

RESULTS

Males with ARMS exhibited significantly poorer social functioning and more severe asociality of negative symptoms than female counterparts. Mediation analysis revealed that sex difference in social functioning became statistically insignificant when asocality was included in the model, indicating that asociality mediated the relationship between sex and social functioning. No sex differences were observed in other core domains of negative symptoms, other symptom dimensions, cognitive measures and role functioning.

CONCLUSIONS

This study suggests that sex differences in ARMS may be less pronounced that those observed in established psychotic disorders. Our findings of differential pattern of asociality between sexes and its mediating role on sex difference in social functioning underscore the importance in investigating negative symptoms at a separable domain-level. Further research is required to identify sex-specific predictors of longitudinal outcomes in at-risk populations.

The inconsistent mediating effect of catechol O methyl transferase Val158Met polymorphism on the sex difference of cognitive impairment in schizophrenia patients

OBJECTIVE

Schizophrenia is a multifaceted mental disorder characterized by heterogeneous positive/negative symptoms and cognitive deficits. Sex differences have been reported in various aspects of the disease. However, the underlying genetic reasons remain unelucidated. Recent studies show that the influence of COMT Val158Met (rs4680) variation is sexually dimorphic. Thus, this study aims to explore whether there is an effect of the interaction between COMT Val158Met (rs4680) polymorphism and sex on patients' clinical characteristics and cognitive function.

MATERIALS AND METHODS

We recruited 367 in patients with chronic schizophrenia (246 males and 121 females) and 419 healthy controls (172 males and 247 females). The cognitive performance was assessed by Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and the COMT Val158Met (rs4680) polymorphism is genotyped. The psychopathological symptoms of the patients were assessed by the Positive and Negative Syndrome Scale (PANSS).

RESULTS

We find that male patients had a significantly higher proportion of carrying the Val allele and Val/Val carriers exhibited more severe positive symptoms and cognitive impairment than Met carriers. COMT Val158Met (rs4680) polymorphism inconsistently mediated the relationship between sex and cognitive performance in schizophrenia patients.

CONCLUSION

These findings suggest that COMT Val158Met (rs4680) polymorphism is associated with the risk and severity of schizophrenia in a sexually dimorphic way and contributes more to the clinical symptoms and cognitive impairment in male patients with schizophrenia.

Sex Differences in Obesity and Cognitive Function in Chinese Elderly Patients With Chronic Schizophrenia

BACKGROUND

It is well known that schizophrenia is associated with sex differences. However, no study has explored the sex differences in obesity and cognitive function in elderly Chinese patients with schizophrenia.

OBJECTIVE

This study aimed to compare sex differences in obesity and cognitive function in elderly Chinese individuals with schizophrenia.

METHODS

A total of 304 elderly patients with schizophrenia and 130 sex- and age-matched healthy controls from the community were recruited. Demographic, clinical, and lipid parameters were collected for all subjects. The Montreal Cognitive Assessment (MoCA) was used to assess the global cognitive functions of the participants, while the Positive and Negative Syndrome Scale (PANSS) was used to assess psychopathological symptoms in patients with schizophrenia.

RESULTS

Of the patients with schizophrenia, the prevalence of obesity in men and women was 11.7% (19/163) and 21.3% (30/141), respectively. The score (14.51 ± 6.504) of MOCA in elderly male patients with schizophrenia was significantly higher than that (11.40 ± 6.822) in female patients. There was a positive correlation between the MOCA scores and body mass index (BMI) (r=0.206, p=0.018) in male elderly patients with schizophrenia. Conversely, the MOCA scores of female elderly patients with schizophrenia did not correlate with BMI (p>0.05). However, we found no sex differences in obesity and cognition among control older adults.

CONCLUSIONS

Our findings suggest that there are significant sex differences in obesity and cognitive function in elderly Chinese patients with schizophrenia.

Trends and Gender Differences in Mental Disorders in Hospitalized Patients in Thailand

Previous studies have shown that gender differences play a substantial role in the influence of mental disorders. This study was designed to investigate gender differences in mental disorders by presenting odd ratio (OR) trends and cumulative effects over a period of 13 years in Thailand. This observational study used hospital data from the Ministry of Public Health on selected patients admitted to inpatient departments in public hospitals with mental disorders, according to ICD-10 cause groups from 2007 to 2019, counting from more than 1,90,000 cases in 2007 to more than 4,00,000 cases in 2019. Data were collected from the Thailand Ministry of Public Health website. The results indicate that compared to women, men were positively related to five mental disorders revealed by the OR and the ratio per 100,000 population (mean and SD): psychoactive alcohol use (OR = 7.31-9.07, 271.19 (59.26)), substance abuse (OR = 5.06-7.82, 59.25 (33.71)), schizophrenia (OR = 1.64-1.93, 108.32 (19.62)), mental retardation (OR = 1.15-1.58, 10.64 (1.88)), and other mental and behavioral disorders (OR = 1.10-1.55, 70.67 (22.75)). Three mental disorders in men were found to be negatively related: neurotic and related disorders (OR=.34-.46, 27.98 (3.26)), mood (affective) disorders (OR = .44-.56, 31.91 (9.59)), and dementia (OR = .78-10.82, 13.75 (2.73)). Gender can become a key biological element that contributes to the dissimilarity of mental illness. Preventive care for men and women should, therefore, be prioritized for health conditions separately. More specifically, screening and detection, and providing appropriate intervention.

Association of Negative Symptoms of Schizophrenia Assessed by the BNSS and SNS Scales With Neuropsychological Performance: A Gender Effect

Objective: The relationship between negative symptoms and neurocognitive performance in schizophrenia is well documented, but the mechanism of these connections remains unclear. The study aims to measure the relationship between the results on the new scales for the assessment of negative symptoms such as Brief Negative Symptom Scale (BNSS) and Self-evaluation of Negative Symptoms (SNS), and the results of some neurocognition tests. The second aim is to assess a possible gender effect on these associations. Methods: The study included 80 patients (40 men, 40 women) with schizophrenia, aged 19-63 (mean 38 years), during the improvement period (total PANSS score <80, unchanged pharmacological treatment in the last 3 weeks). They were assessed using the BNSS, SNS, Personal and Social Performance (PSP) scales, and the tests for neuropsychological performance such as the Trail Making Test (TMT-A, TMT-B), Stroop Color-Word Interference Test, Verbal fluency tests (VFT), Category fluency test (CFT), and Digit Symbol Substitution Test (DSST). Results: Male patients obtained higher scores than females on some PANSS and BNSS items. No gender differences were observed for the SNS scale. Female patients scored better in the PSP and CFT. In male patients, a significant positive correlation between the intensity of negative symptoms measured by the BNSS and the results of PSP with the Trail Making Test was observed. In female patients, we found a positive correlation between the results of BNSS and PSP with the Stroop Color-Word Interference Test. Conclusion: The obtained results confirm the relationship between negative symptoms and neurocognition in schizophrenia patients. However, in male and female patients such association was observed for different cognitive domains. Further research is needed to explain the nature of these differences.

Androgen Effects on Neural Plasticity

Androgens are synthesized in the brain, gonads, and adrenal glands, in both sexes, exerting physiologically important effects on the structure and function of the central nervous system. These effects may contribute to the incidence and progression of neurological disorders such as autism spectrum disorder, schizophrenia, and Alzheimer's disease, which occur at different rates in males and females. This review briefly summarizes the current state of knowledge with respect to the neuroplastic effects of androgens, with particular emphasis on the hippocampus, which has been the focus of much of the research in this field.

Sex Difference in Comorbid Depression in First-Episode and Drug-Naive Patients With Schizophrenia: Baseline Results From the Depression in Schizophrenia in China Study

OBJECTIVE

Comorbid depression is common in schizophrenia, and sex differences are prominent in many aspects of schizophrenia. However, few studies have investigated sex difference in comorbid depression in schizophrenia. This large sample study aimed to investigate sex differences in first-episode drug-naive (FEDN) patients with schizophrenia comorbid major depressive episode (SZ-MDE).

METHODS

A total of 996 FEDN patients with schizophrenia (472 males/524 females) were recruited. The 17-item Hamilton Depression Rating Scale and Positive and Negative Syndrome Scale (PANSS) were applied.

RESULTS

There was no difference in the prevalence of comorbid MDE between male and female patients with schizophrenia. Among SZ-MDE patients, men had more severe psychotic symptoms (scores of PANSS total scale, negative scale, and general psychopathology scale), more severe depressive symptoms, and higher proportion of severe depression than women (all p < .001). The early onset age of schizophrenia, smoking, and PANSS positive score were the risk factors for comorbid MDE only in female patients with schizophrenia (all p < .05). Furthermore, in female patients with SZ-MDE, smoking was associated with the severity category of depression (p = .001, odds ratio = 2.70). Multiple variable regression demonstrated that the Hamilton Depression Rating Scale score correlated with PANSS general psychopathology (p = .01) and total scores (p = .04) in female SZ-MDE.

CONCLUSIONS

Our results indicate sex differences in proportion of severe depression, clinical symptoms, and factors of comorbid MDE in FEDN patients with schizophrenia. These sex differences have clinical implications for the treatment of depression as related to the nature and severity of psychopathological symptoms in patients with schizophrenia.

Subtypes of schizophrenia identified by multi-omic measures associated with dysregulated immune function

Epigenetic modifications are plausible molecular sources of phenotypic heterogeneity across schizophrenia patients. The current study investigated biological heterogeneity in schizophrenia using peripheral epigenetic profiles to delineate illness subtypes independent of their phenomenological manifestations. We applied epigenome-wide profiling with a DNA methylation array from blood samples of 63 schizophrenia patients and 59 healthy controls. Non-negative matrix factorization (NMF) and k-means clustering were performed to identify DNA methylation-related patient subtypes. The validity of the partition was tested by assessing the profile of the T cell receptor (TCR) repertoires. The uniqueness of the identified subtypes in relation to brain structural and clinical measures were evaluated. Two distinct patterns of DNA methylation profiles were identified in patients. One subtype (60.3% of patients) showed relatively limited changes in methylation levels and cell composition compared to controls, while a second subtype (39.7% of patients) exhibited widespread methylation level alterations among genes enriched in immune cell activity, as well as a higher proportion of neutrophils and lower proportion of lymphocytes. Differentiation of the two patient subtypes was validated by TCR repertoires, which paralleled the partition based on DNA methylation profiles. The subtype with widespread methylation modifications had higher symptom severity, performed worse on cognitive measures, and displayed greater reductions in fractional anisotropy of white matter tracts and evidence of gray matter thickening compared to the other subtype. Identification of a distinct subtype of schizophrenia with unique molecular, cerebral, and clinical features provide a novel parcellation of the schizophrenia syndrome with potential to guide development of individualized therapeutics.

Sex-specific effects of polygenic risk for schizophrenia on lifespan cognitive functioning in healthy individuals

Polygenic risk for schizophrenia has been associated with lower cognitive ability and age-related cognitive change in healthy individuals. Despite well-established neuropsychological sex differences in schizophrenia patients, genetic studies on sex differences in schizophrenia in relation to cognitive phenotypes are scarce. Here, we investigated whether the effect of a polygenic risk score (PRS) for schizophrenia on childhood, midlife, and late-life cognitive function in healthy individuals is modified by sex, and if PRS is linked to accelerated cognitive decline. Using a longitudinal data set from healthy individuals aged 25-100 years (N = 1459) spanning a 25-year period, we found that PRS was associated with lower cognitive ability (episodic memory, semantic memory, visuospatial ability), but not with accelerated cognitive decline. A significant interaction effect between sex and PRS was seen on cognitive task performance, and sex-stratified analyses showed that the effect of PRS was male-specific. In a sub-sample, we observed a male-specific effect of the PRS on school performance at age 12 (N = 496). Our findings of sex-specific effects of schizophrenia genetics on cognitive functioning across the lifespan indicate that the effects of underlying disease genetics on cognitive functioning is dependent on biological processes that differ between the sexes.

Sex-differential associations between cognitive impairments and white matter abnormalities in first episode and drug-naïve schizophrenia

AIM

Previous evidence has suggested that schizophrenia patients may display sex differences in cognitive impairments and cognitive impairments are related to disrupted white matter (WM) microstructure. The current research aims to address the intriguing possibility for the sex-specific association between cognitive deficits and WM abnormalities in first-episode and drug-naïve schizophrenia.

METHODS

Cognitive performance on the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) was measured in 39 FEND patients (females:males = 23:16) and 30 healthy controls (females:males = 17:13), together with whole-brain WM fractional anisotropy (FA) values determined using voxel-based diffusion tensor imaging. Correlations between cognitive performance and FA values were assessed.

RESULTS

Patients performed significantly worse than healthy controls in the total score and most of the subscores of MCCB. Female patients displayed better cognitive performance than male patients on the Trail Making A Test, the Hopkins Verbal Learning Test and the Spatial Span Test in the Wechsler Memory Scale. More importantly, sex-differential association between cognitive performance and FA values was found in patients, but not in healthy controls. In particular, FA values in the cerebellum were negatively correlated with the continuous performance and digital sequence scores in male patients but positively correlated with the performance on the Spatial Span Test in the Wechsler Memory Scale in female patients.

CONCLUSIONS

These findings suggest sex-specific neurobiological substrates involved in cognitive deficits in early-onset schizophrenia and have important implications for differentially targeted interventions between males and females.

Stratification by Sex and Hormone Level When Contrasting Men and Women in Schizophrenia Trials Will Improve Personalized Treatment

BACKGROUND

Sex and gender differences have been reported in the prevalence, expression, treatment response, and outcome of schizophrenia, but most reports are based on relatively small samples that have not been stratified for the impact of sex hormone levels. This literature review aims to show how women's hormone levels can impact the results of male/female comparisons.

METHODS

This is a narrative review of data from publications of the last decade.

RESULTS

Epidemiologic evidence, reports of the impact of hormones on cognition, results of sexually dimorphic responses to treatment, and male/female trajectories of illness over time all suggest that female hormone fluctuations exert major effects on male/female differences in schizophrenia.

CONCLUSIONS

Information on hormonal status in women participants is rarely available in clinical studies in schizophrenia, which makes male/female comparisons largely uninterpretable. These are the current challenges. Opportunities for individualized treatment are growing, however, and will undoubtedly result in improved outcomes for both women and men in the future.

Sex difference in the interrelationship between TNF-α and oxidative stress status in first-episode drug-naïve schizophrenia

Background

Increasing evidence indicates that dysregulated TNF-α and oxidative stress (OxS) contribute to the pathophysiology of schizophrenia. Additionally, previous evidence has demonstrated sex differences in many aspects of schizophrenia including clinical characteristics, cytokines, and OxS markers. However, to the best of our knowledge, there is no study investigating sex differences in the association between TNF-α, the OxS system, and their interaction with clinical symptoms in schizophrenia patients, especially in first-episode drug-naïve (FEDN) patients.

Methods

A total of 119 FEDN schizophrenia patients and 135 healthy controls were recruited for this study. Serum TNF-α, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA) were measured. The Positive and Negative Syndrome Scale (PANSS) was applied to evaluate psychotic symptoms. Two-way ANOVA, partial correlation analysis, and multivariate regression analysis were performed.

Results

A sex difference in MDA levels was demonstrated only in healthy controls (F = 7.06, p_Bonferroni = 0.045) and not seen in patients. Furthermore, only male patients had higher MDA levels than male controls (F = 8.19, p_Bonferroni = 0.03). Additionally, sex differences were observed in the association of TNF-α and MDA levels with psychotic symptoms (all p_Bonferroni < 0.05). The interaction of TNF-α and MDA was only associated with general psychopathology symptom in male patients (B = − 0.07, p = 0.02).

Conclusion

Our results demonstrate the sex difference in the relationship between TNF-α, MDA, and their interaction with psychopathological symptoms of patients with schizophrenia.

How psychosis interrupts the lives of women and men differently: a qualitative comparison

PURPOSE

Psychosis disrupts how persons experience themselves and their lives. Despite knowledge that gender differences have been noted in presentation and course of psychosis symptoms, little is known about differences in how men and women experience these disruptions.

METHOD

The narratives of 26 men and 27 women diagnosed with psychosis, matched on age, education, and race, of the impact of psychosis on one's life, were compared. Using secondary data from semi-structured interviews, themes were identified using inductive, phenomenological qualitative analyses.

RESULTS

Women and men discussed psychosis-related interruptions to the roles and relationships that shape their identity. Both genders discussed the impact of psychosis on their sense of self, work, and relationships. Nuanced gender differences emerged, informing unique areas of challenge related to (1) parenting and loss of parenting roles, (2) work and loss or changes in work trajectories, (3) isolation and strain on interpersonal relationships, and (4) manifestations of stigma.

CONCLUSIONS

Psychosis may disrupt distinct aspects of life for men and women. Each gender faces the intersection of socially informed expectations that impact one's experiences of stigma, expectations of others, and manifestations of losses felt in one's role and sense of identity. Findings inform important considerations for therapy and other services.

PRACTITIONER POINTS

Gender-based socialized expectations, losses, and challenges that accompany psychosis are important areas for therapeutic consideration. Current treatments may neglect challenges that are more commonly experienced by women with psychosis.

Sex differences between serum total bilirubin levels and cognition in patients with schizophrenia

BACKGROUND

Cognitive deficits are common in patients with schizophrenia (SCZ). Abnormal serum total bilirubin (TBIL) levels have been involved in cognitive deficits associated with neuropsychiatric diseases such as mild cognitive impairment and subcortical ischemic vascular disease. However, this relationship has not yet been fully investigated in patients with SCZ. Therefore, the aim of this study was to investigate the association between the serum TBIL concentration and cognitive deficits in SCZ patients and to determine whether a sex difference exists in the association.

METHODS

A total of 455 participants were eligible and included in this cross-sectional study. Cognition was evaluated using the Montreal Cognitive Assessment. Serum TBIL concentration was measured with an automatic biochemistry analyzer according to the routine protocol in the hospital medical laboratory.

RESULTS

Serum TBIL levels were lower in the cognition impairment group than in the cognition normal group in male patients. In contrast, serum TBIL levels tended to be increased in the cognition impairment group in female patients, although the difference was not significant. Further stepwise multiple regression analysis stratified by sex showed that serum TBIL was independently and positively associated with cognitive function in male patients but not in female patients. Moreover, the association between serum TBIL level and cognitive function was also identified by the propensity score matching (PSM) method in male patients, but not in female patients.

CONCLUSION

These findings suggest that lower serum TBIL levels may be associated with cognitive impairment in male SCZ patients.

Group and sex differences in social cognition in bipolar disorder, schizophrenia/schizoaffective disorder and healthy people

BACKGROUND

Impairment of social cognition is documented in bipolar disorder (BD) and schizophrenia/schizoaffective disorder (SCH). In healthy individuals, women perform better than men in some of its sub-domains. However, in BD and SCH the results are mixed. Our aim was to compare emotion recognition, affective Theory of Mind (ToM) and first- and second-order cognitive ToM in BD, SCH and healthy subjects, and to investigate sex-related differences.

METHODS

120 patients (BD = 60, SCH = 60) and 40 healthy subjects were recruited. Emotion recognition was assessed by the Pictures of Facial Affect (POFA) test, affective ToM by the Reading the Mind in the Eyes Test (RMET) and cognitive ToM by several false-belief stories. Group and sex differences were analyzed using parametric (POFA, RMET) and non-parametric (false-belief stories) tests. The impact of age, intelligence quotient (IQ) and clinical variables on patient performance was examined using a series of linear/logistic regressions.

RESULTS

Both groups of patients performed worse than healthy subjects on POFA, RMET and second-order false-belief (p < 0.001), but no differences were found between them. Instead, their deficits were related to older age and/or lower IQ (p < 0.01). Subthreshold depression was associated with a 6-fold increased risk of first-order false-belief failure (p < 0.001). Sex differences were only found in healthy subjects, with women outperforming men on POFA and RMET (p ≤ 0.012), but not on first/second-order false-belief.

LIMITATIONS

The cross-sectional design does not allow for causal inferences.

CONCLUSION

BD and SCH patients had deficits in emotion recognition, affective ToM, and second-order cognitive ToM, but their performance was comparable to each other, highlighting that the differences between them may be subtler than previously thought. First-order cognitive ToM remained intact, but subthreshold depression altered their normal functioning. Our results suggest that the advantage of healthy women in the emotional and affective aspects of social cognition would not be maintained in BD and SCH.

S-Palmitoylation of Synaptic Proteins as a Novel Mechanism Underlying Sex-Dependent Differences in Neuronal Plasticity

Although sex differences in the brain are prevalent, the knowledge about mechanisms underlying sex-related effects on normal and pathological brain functioning is rather poor. It is known that female and male brains differ in size and connectivity. Moreover, those differences are related to neuronal morphology, synaptic plasticity, and molecular signaling pathways. Among different processes assuring proper synapse functions are posttranslational modifications, and among them, S-palmitoylation (S-PALM) emerges as a crucial mechanism regulating synaptic integrity. Protein S-PALM is governed by a family of palmitoyl acyltransferases, also known as DHHC proteins. Here we focused on the sex-related functional importance of DHHC7 acyltransferase because of its S-PALM action over different synaptic proteins as well as sex steroid receptors. Using the mass spectrometry-based PANIMoni method, we identified sex-dependent differences in the S-PALM of synaptic proteins potentially involved in the regulation of membrane excitability and synaptic transmission as well as in the signaling of proteins involved in the structural plasticity of dendritic spines. To determine a mechanistic source for obtained sex-dependent changes in protein S-PALM, we analyzed synaptoneurosomes isolated from DHHC7-/- (DHHC7KO) female and male mice. Our data showed sex-dependent action of DHHC7 acyltransferase. Furthermore, we revealed that different S-PALM proteins control the same biological processes in male and female synapses.

SREBP-1c Deficiency Affects Hippocampal Micromorphometry and Hippocampus-Dependent Memory Ability in Mice

Changes in structural and functional neuroplasticity have been implicated in various neurological disorders. Sterol regulatory element-binding protein (SREBP)-1c is a critical regulatory molecule of lipid homeostasis in the brain. Recently, our findings have shown the potential involvement of SREBP-1c deficiency in the alteration of novel modulatory molecules in the hippocampus and occurrence of schizophrenia-like behaviors in mice. However, the possible underlying mechanisms, related to neuronal plasticity in the hippocampus, are yet to be elucidated. In this study, we investigated the hippocampus-dependent memory function and neuronal architecture of hippocampal neurons in SREBP-1c knockout (KO) mice. During the passive avoidance test, SREBP-1c KO mice showed memory impairment. Based on Golgi staining, the dendritic complexity, length, and branch points were significantly decreased in the apical cornu ammonis (CA) 1, CA3, and dentate gyrus (DG) subregions of the hippocampi of SREBP-1c KO mice, compared with those of wild-type (WT) mice. Additionally, significant decreases in the dendritic diameters were detected in the CA3 and DG subregions, and spine density was also significantly decreased in the apical CA3 subregion of the hippocampi of KO mice, compared with that of WT mice. Alterations in the proportions of stubby and thin-shaped dendritic spines were observed in the apical subcompartments of CA1 and CA3 in the hippocampi of KO mice. Furthermore, the corresponding differential decreases in the levels of SREBP-1 expression in the hippocampal subregions (particularly, a significant decrease in the level in the CA3) were detected by immunofluorescence. This study suggests that the contributions of SREBP-1c to the structural plasticity of the mouse hippocampus may have underlain the behavioral alterations. These findings offer insights into the critical role of SREBP-1c in hippocampal functioning in mice.

Functional connectome-wide associations of schizophrenia polygenic risk

Schizophrenia is a highly heritable mental disorder characterized by functional dysconnectivity across the brain. However, the relationships between polygenic risk factors and connectome-wide neural mechanisms are unclear. Here, combining genetic and multiparadigm fMRI data of 623 healthy Caucasian adults drawn from the Human Connectome Project, we found that higher schizophrenia polygenic risk scores were significantly correlated with lower functional connectivity in a large-scale brain network primarily encompassing the visual system, default-mode system, and frontoparietal system. Such correlation was robustly observed across multiple fMRI paradigms, suggesting a brain-state-independent neural phenotype underlying individual genetic liability to schizophrenia. Moreover, using an independent clinical dataset acquired from the Consortium for Neuropsychiatric Phenomics, we further demonstrated that the connectivity of the identified network was reduced in patients with schizophrenia and significantly correlated with general cognitive ability. These findings provide the first evidence for connectome-wide associations of schizophrenia polygenic risk at the systems level and suggest that disrupted integration of sensori-cognitive information may be a hallmark of genetic effects on the brain that contributes to the pathogenesis of schizophrenia.

Considering Sex as a Biological Variable in Basic and Clinical Studies: An Endocrine Society Scientific Statement

In May 2014, the National Institutes of Health (NIH) stated its intent to "require applicants to consider sex as a biological variable (SABV) in the design and analysis of NIH-funded research involving animals and cells." Since then, proposed research plans that include animals routinely state that both sexes/genders will be used; however, in many instances, researchers and reviewers are at a loss about the issue of sex differences. Moreover, the terms sex and gender are used interchangeably by many researchers, further complicating the issue. In addition, the sex or gender of the researcher might influence study outcomes, especially those concerning behavioral studies, in both animals and humans. The act of observation may change the outcome (the "observer effect") and any experimental manipulation, no matter how well-controlled, is subject to it. This is nowhere more applicable than in physiology and behavior. The sex of established cultured cell lines is another issue, in addition to aneuploidy; chromosomal numbers can change as cells are passaged. Additionally, culture medium contains steroids, growth hormone, and insulin that might influence expression of various genes. These issues often are not taken into account, determined, or even considered. Issues pertaining to the "sex" of cultured cells are beyond the scope of this Statement. However, we will discuss the factors that influence sex and gender in both basic research (that using animal models) and clinical research (that involving human subjects), as well as in some areas of science where sex differences are routinely studied. Sex differences in baseline physiology and associated mechanisms form the foundation for understanding sex differences in diseases pathology, treatments, and outcomes. The purpose of this Statement is to highlight lessons learned, caveats, and what to consider when evaluating data pertaining to sex differences, using 3 areas of research as examples; it is not intended to serve as a guideline for research design.

The Role of G Protein-Coupled Receptors (GPCRs) and Calcium Signaling in Schizophrenia. Focus on GPCRs Activated by Neurotransmitters and Chemokines

Schizophrenia is a common debilitating disease characterized by continuous or relapsing episodes of psychosis. Although the molecular mechanisms underlying this psychiatric illness remain incompletely understood, a growing body of clinical, pharmacological, and genetic evidence suggests that G protein-coupled receptors (GPCRs) play a critical role in disease development, progression, and treatment. This pivotal role is further highlighted by the fact that GPCRs are the most common targets for antipsychotic drugs. The GPCRs activation evokes slow synaptic transmission through several downstream pathways, many of them engaging intracellular Ca²⁺ mobilization. Dysfunctions of the neurotransmitter systems involving the action of GPCRs in the frontal and limbic-related regions are likely to underly the complex picture that includes the whole spectrum of positive and negative schizophrenia symptoms. Therefore, the progress in our understanding of GPCRs function in the control of brain cognitive functions is expected to open new avenues for selective drug development. In this paper, we review and synthesize the recent data regarding the contribution of neurotransmitter-GPCRs signaling to schizophrenia symptomology.

Prenatal Kynurenine Elevation Elicits Sex-Dependent Changes in Sleep and Arousal During Adulthood: Implications for Psychotic Disorders

Dysregulation of the kynurenine pathway (KP) of tryptophan catabolism has been implicated in psychotic disorders, including schizophrenia and bipolar disorder. Kynurenic acid (KYNA) is a KP metabolite synthesized by kynurenine aminotransferases (KATs) from its biological precursor kynurenine and acts as an endogenous antagonist of N-methyl-D-aspartate and α7-nicotinic acetylcholine receptors. Elevated KYNA levels found in postmortem brain tissue and cerebrospinal fluid of patients are hypothesized to play a key role in the etiology of cognitive symptoms observed in psychotic disorders. Sleep plays an important role in memory consolidation, and sleep disturbances are common among patients. Yet, little is known about the effect of altered KP metabolism on sleep-wake behavior. We presently utilized a well-established experimental paradigm of embryonic kynurenine (EKyn) exposure wherein pregnant dams are fed a diet laced with kynurenine the last week of gestation and hypothesized disrupted sleep-wake behavior in adult offspring. We examined sleep behavior in adult male and female offspring using electroencephalogram and electromyogram telemetry and determined sex differences in sleep and arousal in EKyn offspring. EKyn males displayed reduced rapid eye movement sleep, while female EKyn offspring were hyperaroused compared to controls. We determined that EKyn males maintain elevated brain KYNA levels, while KYNA levels were unchanged in EKyn females, yet the activity levels of KAT I and KAT II were reduced. Our findings indicate that elevated prenatal kynurenine exposure elicits sex-specific changes in sleep-wake behavior, arousal, and KP metabolism.

Sexual dimorphic effects of restraint stress on prefrontal cortical function are mediated by glucocorticoid receptor activation

Stress, a major regulator and precipitating factor of cognitive and emotional disorders, differentially manifests between males and females. Our aim was to investigate the mechanisms underlying the sexual dimorphic effects of acute restraint stress (RS) on males and females on the function of the prefrontal cortex (PFC). Adult male and female mice were subjected to RS or left in their home-cage (NR), and then tested in the light-dark test followed by the temporal order object recognition (TOR) task. Female mice exhibited increased anxiety-like levels, whereas male mice only showed deficits in the TOR task. When the behavioural tests were conducted 24 hr following restraint stress (RS24), only the reduced performance in the TOR task in male mice persisted. In a different cohort, evoked field excitatory postsynaptic potentials (fEPSPs) were recorded in layer II of acute PFC slices, immediately or 24 hr after RS. Long-term potentiation (LTP) was significantly reduced in RS and RS24 male, but not female, compared with their respective NR group. LTP in PFC slices incubated with corticosterone showed significantly reduced LTP only in males. To determine whether glucocorticoid signalling is implicated in the RS-induced behavioural effects, a different cohort of mice was administered mifepristone, a corticosterone receptor antagonist. Mifepristone administration 1 hr before RS prevented the effects of RS on the TOR task in males, but not anxiety. In conclusion, RS has differential effects on recency memory and anxiety, in males and females, which are partly mediated by the effects of corticosterone signalling on synaptic plasticity.

Prepubertal Environmental Enrichment Prevents Dopamine Dysregulation and Hippocampal Hyperactivity in MAM Schizophrenia Model Rats

BACKGROUND

Schizophrenia (SCZ) is a neurodevelopmental disorder with a progressive, prolonged course. Early prevention for SCZ is promising but overall lacks support from preclinical evidence. Previous studies have tested environmental enrichment (EE) in certain models of SCZ and discovered a broadly beneficial effect in preventing behavioral abnormalities relevant, yet not specific, to the disorder. Nonetheless, whether EE can prevent dopamine (DA) dysregulation, a hallmark of psychosis and SCZ, had not been tested.

METHODS

Using the MAM (methylazoxymethanol acetate) rat model of schizophrenia and saline-treated control animals, we investigated the long-term electrophysiological effects of prepubertal (postnatal day 21-40) EE on DA neurons, pyramidal neurons in the ventral hippocampus, and projection neurons in the basolateral amygdala. Anxiety-related behaviors in the elevated plus maze and locomotor responses to amphetamine were also analyzed.

RESULTS

Prepubertal EE prevented the increased population activity of DA neurons and the associated increase in locomotor response to amphetamine. Prepubertal EE also prevented hyperactivity in the ventral hippocampus but did not prevent hyperactivity in the basolateral amygdala. Anxiety-like behaviors in MAM rats were not ameliorated by prepubertal exposure to EE.

CONCLUSIONS

Twenty-day prepubertal EE is sufficient to prevent DA hyperresponsivity in the MAM model, measured by electrophysiological recordings and locomotor response to amphetamine. This effect is potentially mediated by normalizing excessive firing in the ventral hippocampus without affecting anxiety-like behaviors and basolateral amygdala firing. This study identified EE as a useful preventative approach that may protect against the pathophysiological development of SCZ.

Gender-specific approach in psychiatric diseases: Because sex matters

In both animals and human beings, males and females differ in their genetic background and hormonally driven behaviour and show sex-related differences in brain activity and response to internal and external stimuli. Gender-specific medicine has been a neglected dimension of medicine for long time, and only in the last three decades it is receiving the due scientific and clinical attention. Research has recently begun to identify factors that could provide a neurobiological basis for gender-based differences in health and disease and to point to gonadal hormones as important determinants of male-female differences. Animal studies have been of great help in understanding factors contributing to sex-dependent differences and sex hormones action. Here we review and discuss evidence provided by clinical and animal studies in the last two decades showing gender (in humans) and sex (in animals) differences in selected psychiatric disorders, namely eating disorders (anorexia nervosa, bulimia nervosa, binge eating disorder), schizophrenia, mood disorders (anxiety, depression, obsessive-compulsive disorder) and neurodevelopmental disorders (autism spectrum disorders, attention-deficit/hyperactivity disorder).

Updating and characterizing neuroanatomical markers in high-risk subjects, recently diagnosed and chronic patients with schizophrenia: A revised coordinate-based meta-analysis

Characterizing neuroanatomical markers of different stages of schizophrenia (SZ) to assess pathophysiological models of how the disorder develops is an important target for the clinical practice. We performed a meta-analysis of voxel-based morphometry studies of genetic and clinical high-risk subjects (g-/c-HR), recently diagnosed (RDSZ) and chronic SZ patients (ChSZ). We quantified gray matter (GM) changes associated with these four conditions and compared them with contrast and conjunctional data. We performed the behavioral analysis and networks decomposition of alterations to obtain their functional characterization. Results reveal a cortical-subcortical, left-to-right homotopic progression of GM loss. The right anterior cingulate is the only altered region found altered among c-HR, RDSZ and ChSZ. Contrast analyses show left-lateralized insular, amygdalar and parahippocampal GM reduction in RDSZ, which appears bilateral in ChSZ. Functional decomposition shows involvement of the salience network, with an enlargement of the sensorimotor network in RDSZ and the thalamus-basal nuclei network in ChSZ. These findings support the current neuroprogressive models of SZ and integrate this deterioration with the clinical evolution of the disease.

A Random Forest Model for Predicting Social Functional Improvement in Chinese Patients with Schizophrenia After 3 Months of Atypical Antipsychotic Monopharmacy: A Cohort Study

PURPOSE

Impaired social functions contribute to the burden of schizophrenia patients and their families, but predictive tools of social functioning prognosis and specific factors are undefined in Chinese clinical practice. This article explores a machine learning tool to identify whether patients will achieve significant social functional improvement after 3 months of atypical antipsychotic monopharmacy and finds the defined risk factors using a multicenter clinical study.

PATIENTS AND METHODS

A multicenter study on atypical antipsychotic (AAP) treatment in Chinese patients with schizophrenia (SALT-C) was conducted from July 2011 to August 2018. Data from 550 patients with AAP monopharmacy from their baseline to their 3-month follow-up were used to establish machine learning tools after screening. The positive outcome was an increase in the Personal and Social Performance (PSP) scale score by ≥10 points. The predictors were a range of investigator-rated assessments on symptoms, functioning, the safety of AAPs and illness history. The Least Absolute Shrinkage and Selection Operator (LASSO) was used for the feature screening and ranking of the predicted variables. The random forest algorithm and five-fold cross-validation for optimizing the model were selected to ensure the generalizability and precision.

RESULTS

There were 137 patients (mean [SD] age, 41.1 [16.8] years; 77 [58.8%] female) who had a good social functional prognosis. A lower PSP score, taking a mood stabilizer, a high total Positive and Negative Symptom Scale (PANSS) and PANSS general subscale score, unemployment, a hepatic injury with medication, comorbid cardiovascular disease and being male predicted poor PSP outcomes. The generalizability of the PSP predictive tool was estimated with the precision-recall curve (accuracy of 79.5%, negative predictive value of 92.6% and positive predictive value of 57.1%) and receiver operating characteristic curve (ROC) (specificity of 81.8% and sensitivity of 78.7%).

CONCLUSION

The machine learning tool established using our current real-world data could assist in predicting PSP outcome by several clinical factors.

ZFP804A mutant mice display sex-dependent schizophrenia-like behaviors

Genome-wide association studies uncovered the association of ZNF804A (Zinc-finger protein 804A) with schizophrenia (SZ). In vitro data have indicated that ZNF804A might exert its biological roles by regulating spine and neurite morphogenesis. However, no in vivo data are available for the role of ZNF804A in psychiatric disorders in general, SZ in particular. We generated ZFP804A mutant mice, and they showed deficits in contextual fear and spatial memory. We also observed the sensorimotor gating impairment, as revealed by the prepulse inhibition test, but only in female ZFP804A mutant mice from the age of 6 months. Notably, the PPI difference between the female mutant and control mice was no longer existed with the administration of Clozapine or after the ovariectomy. Hippocampal long-term potentiation was normal in both genders of the mutant mice. Long-term depression was absent in male mutants, but facilitated in the female mutants. Protein levels of hippocampal serotonin-6 receptor and GABAB1 receptor were increased, while those of cortical dopamine 2 receptor were decreased in the female mutants with no obvious changes in the male mutants. Moreover, the spine density was reduced in the cerebral cortex and hippocampus of the mutant mice. Knockdown of ZFP804A impaired the neurite morphogenesis of cortical and hippocampal neurons, while its overexpression enhanced neurite morphogenesis only in the cortical neurons in vitro. Our data collectively support the idea that ZFP804A/ZNF804A plays important roles in the cognitive functions and sensorimotor gating, and its dysfunction may contribute to SZ, particularly in the female patients.

Gender Differences in Clinical and Psychosocial Features Among Persons With Schizophrenia: A Mini Review

An extensive literature regarding gender differences relevant to several aspects of schizophrenia is nowadays available. It includes some robust findings as well as some inconsistencies. In the present review, we summarize the literature on gender differences in schizophrenia relevant to clinical and social outcome as well as their determinants, focusing on clinical variables, while gender differences on biological factors which may have an impact on the outcome of the disorder were not included herewith. Consistent findings include, in male with respect to female patients, an earlier age of illness onset limited to early- and middle-onset schizophrenia, a worse premorbid functioning, a greater severity of negative symptoms, a lower severity of affective symptoms and a higher rate of comorbid alcohol/substance abuse. Discrepant findings have been reported on gender differences in positive symptoms and in social and non-social cognition, as well as in functional outcome and rates of recovery. In fact, despite the overall finding of a more severe clinical picture in males, this does not seem to translate into a worse outcome. From the recent literature emerges that, although some findings on gender differences in schizophrenia are consistent, there are still aspects of clinical and functional outcome which need clarification by means of further studies taking into account several methodological issues.

Sex-specific sensitivity to methamphetamine-induced schizophrenia-relevant behaviours in neuregulin 1 type III overexpressing mice

BACKGROUND

Gene-environment interactions contribute to schizophrenia aetiology. Neuregulin 1 is a well-established genetic risk factor for schizophrenia, and elevated expression of type III neuregulin 1 mRNA in the dorsolateral prefrontal cortex is observed in patients with a core risk haplotype. A mouse model of type III Nrg1 overexpression (Nrg1 III tg) possesses face and construct validity for schizophrenia; however, the sensitivity of these transgenic mice to environmental risk factors relevant to schizophrenia is unknown.

AIMS

To determine sensitivity of Nrg1 III tg mice to the psychostimulant methamphetamine (METH) in schizophrenia and addiction-relevant behavioural tests.

METHODS

We examined behavioural responses of adult male and female Nrg1 III tg mice METH (1-3 mg/kg) in schizophrenia-relevant paradigms (drug-induced locomotion, sensorimotor gating) and drug reward (conditioned place preference).

RESULTS

Male Nrg1 III tg mice were less sensitive to METH-induced stereotypies, yet showed a greater negative impact of METH on prepulse inhibition compared with wild type-like males. In contrast, female Nrg1 III tg mice were less sensitive to METH-induced locomotion than wild type-like females, while sensorimotor gating was similarly impaired by METH between the genotypes. There were no genotype differences for METH reward, or anxiety-like and exploratory behaviours.

CONCLUSIONS

These results indicate that overexpression of Nrg1 type III modulates schizophrenia-relevant behaviours, and may help to explain increased sensitivity to the psychoactive effects of METH in patients with schizophrenia.

Beyond the Mind-Serum Trace Element Levels in Schizophrenic Patients: A Systematic Review

The alterations in serum trace element levels are common phenomena observed in patients with different psychiatric conditions such as schizophrenia, autism spectrum disorder, or major depressive disorder. The fluctuations in the trace element concentrations might act as potential diagnostic and prognostic biomarkers of many psychiatric and neurological disorders. This paper aimed to assess the alterations in serum trace element concentrations in patients with a diagnosed schizophrenia. The authors made a systematic review, extracting papers from the PubMed, Web of Science, and Scopus databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Among 5009 articles identified through database searching, 59 of them were assessed for eligibility. Ultimately, 33 articles were included in the qualitative synthesis. This review includes the analysis of serum levels of the following trace elements: iron, nickel, molybdenum, phosphorus, lead, chromium, antimony, uranium, magnesium, aluminum, zinc, copper, selenium, calcium, and manganese. Currently, there is no consistency regarding serum trace element levels in schizophrenic patients. Thus, it cannot be considered as a reliable prognostic or diagnostic marker of schizophrenia. However, it can be assumed that altered concentrations of those elements are crucial regarding the onset and exaggeration of either psychotic or negative symptoms or cognitive dysfunctions.

Cognitive function and life quality of patients with moderate-to-severe obstructive sleep apnea-hypopnea syndrome in China

Objective: To investigate the correlation between cognitive function and quality of life in patients with moderate to severe OSAHS, and to further analyze the impact of cognitive domains on QoL in patients with OSAHS.Methods: Pearson analysis was applied to explore the correlation between MoCA score and SAQLI score. It was conducted by collecting the clinical characteristics of patients and the Epworth Sleepiness Scale and Sleep Quality Scale. T-test, a non-parametric test (Mann-Whitney) or chi-square test, and Pearson analysis were used to analyze the relationship between MoCA score and patient clinical characteristics, sleep variables, and SAQLI score.Results: The SAQLI score of the MCI group significantly decreased. Patients in the MCI group had a higher WHR, higher alcohol intake, and a history of hypertension were firmly related to the poor SAQLI (P < 0.05). The Epworth sleepiness scale (ESS) score increased in the MCI group, and the AHI and ODI elevated significantly, which was related to the poorer SAQLI as well (P < 0.05).Conclusion: Cognitive impairment in OSAHS patients is related to QoL reduction.Keywords: cognitive function; Montreal cognitive assessment; obstructive sleep apnea hypopnea syndrome; quality of life; sleep apnea quality of life index.