The relationship between obesity and neurocognitive function in Chinese patients with schizophrenia

Association of EEG and cognitive impairment in overweight and non-overweight patients with schizophrenia

OBJECTIVE

Schizophrenia (SCZ) is a globally prevalent, severe chronic mental disorder, with cognitive dysfunction being one of its core symptoms. Notably, overweight is exceedingly common among individuals with SCZ, and overweight can also impact cognitive function. Therefore, the relationship between overweight and cognition in SCZ is a clinical issue that is in need of research attention.

METHODS

This study enrolled 77 patients with SCZ, including 36 overweight and 41 non-overweight patients. The Positive and Negative Syndrome Scale (PANSS) was used to assess symptom severity, while cognitive functions were evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Electroencephalography (EEG) testing was performed, with power spectral analysis conducted across various frequency bands (δ, θ, α, β, low γ, and high γ).

RESULTS

Compared to non-overweight SCZ patients, those overweight exhibited significantly lower RBANS total and index scores in immediate memory, visuospatial/constructional abilities, and delayed memory. EEG spectral analysis revealed that overweight SCZ patients demonstrated significantly lower oscillation power ratios in the β, low γ, and high γ frequency bands compared to their non-overweight counterparts. Correlation analyses indicated a significant positive relationship between β wave activity and RBANS total scores among overweight SCZ patients, suggesting that reduced β power correlates with more severe cognitive dysfunction.

CONCLUSION

Our findings indicate that overweight SCZ patients experience more severe cognitive impairments in a resting state than those who are not overweight, with significant differences in EEG spectrum observed in the β and γ frequency bands. Additionally, our study establishes a correlation between various EEG spectrum dimensions and cognition. This research highlights the effects of overweight on cognition in individuals with SCZ. Additionally, employing EEG technology to study cognitive function in overweight SCZ patients can offer valuable electrophysiological insights.

Association of obesity to reaction time and visual memory in schizophrenia

Background

Both overweight and cognitive deficits are common among people with schizophrenia (SZ) and schizoaffective disorder. The results in earlier studies have been inconsistent on whether overweight is associated with cognitive deficits in psychotic disorders.

Aims

Our aim in this study was to detect possible associations between obesity and cognitive deficits among study participants with SZ and schizoaffective disorder.

Methods

The study sample included 5382 participants with a clinical diagnosis of SZ or schizoaffective disorder selected from the Finnish SUPER study. Obesity was measured both with body-mass index and waist circumference. The cognitive performance was evaluated with two tests from the Cambridge automated neuropsychological test battery: Reaction time was evaluated with the 5-choice serial reaction time task. Visual memory was evaluated with the paired associative learning test. The final analysis included a total sample of 4498 participants applicable for the analysis of the reaction time and 3967 participants for the analysis of the visual memory.

Results

Obesity measured with body-mass index was associated with better performance in reaction time task among both female and male participants. Among male participants, overweight was associated with better performance in the visual memory test. The waist circumference was not associated with cognitive measures.

Conclusions

The results suggest that obesity in people with SZ or schizoaffective disorder might not be associated with cognitive deficits but instead with better cognitive performance. The results were opposite from earlier literature on the general population. More research is required to better understand whether the results might be partly caused by the differences in the etiology of obesity between the general population and people with SZ.

The Bidirectional Relationship between Weight Gain and Cognitive Function in First-Episode Schizophrenia: A Longitudinal Study in China

Patients with schizophrenia often encounter notable weight gain during their illness, heightening the risk of metabolic diseases. While previous studies have noted a correlation between obesity and cognitive impairment in schizophrenia, many were cross-sectional, posing challenges in establishing a causal relationship between weight gain and cognitive function. The aim of this longitudinal study is to examine the relationship between weight gain and cognitive function in patients with first-episode schizophrenia (FES) during the initial 6-month antipsychotic treatments. Employing linear and logistic regression analyses, the study involved 337 participants. Significantly, baseline scores in processing speed (OR = 0.834, p = 0.007), working memory and attention (OR = 0.889, p = 0.043), and executive function (OR = 0.862, p = 0.006) were associated with clinically relevant weight gain (CRW, defined as an increase in body weight > 7%) at the 6-month endpoint. On the other hand, CRW correlated with improvements in the Brief Visuospatial Memory Test (p = 0.037). These findings suggest that patients with lower baseline cognitive performance undergo more substantial weight gain. Conversely, weight gain was correlated with cognitive improvements, particularly in the domain of visual learning and memory. This suggested a potential bidirectional relationship between weight gain and cognitive function in first-episode schizophrenia patients.

Association between increased BMI and cognitive function in first-episode drug-naïve male schizophrenia

Objective

Although the adverse effects of obesity in schizophrenia are documented, there is limited research exists on the implications for untreated initial schizophrenia. Our investigation aimed to explore the connections between BMI and cognitive function in first-episode drug-naïve (FEDN)schizophrenia.

Methods

We enrolled 143 FEDN schizophrenia patients, and collected data on their body mass index, fasting blood glucose and lipid levels. Cognitive function was measured with the MATRICS Consensus Cognitive Battery (MCCB). Using correlation and regression analysis to assess the relationship between BMI and cognitive performance.

Results

The prevalence rate of overweight plus obesity in FEDN schizophrenia patients was 33.57%. Patients with FEDN schizophrenia exhibited extensive cognitive impairment, and those who were overweight/obesity demonstrated more severe impairments in working memory and visual learning when compared to normal/under weight counterparts. Correlation analysis indicated a negative association between working memory and BMI and TG, as well as a link between visual learning and BMI and LDL-C. Multiple linear regression analysis revealed that a higher BMI predicted a decrease in working memory in FEDN schizophrenia patients.

Conclusion

Our results indicate that the rate of overweight plus obesity is high in FEDN schizophrenia patients, and there is an association between BMI and cognitive function in schizophrenia, particularly in relation to working memory.

Weight gain, gender, and antipsychotics: a disproportionality analysis of the FDA Adverse Event Reporting System database (FAERS)

INTRODUCTION

Side effects are a very important aspect of antipsychotic treatments. Weight gain is an important side effect that jeopardizes the uninterrupted therapy administration, especially in patients with psychiatric conditions. This case-non-case pharmacovigilance study aims at investigating in a real-world adverse event reporting system whether several antipsychotics increase the risk of weight gain reporting, and the differences among men and women as far as weight gain as a reported adverse event is concerned.

AREAS COVERED

Adverse event reports submitted to the FDA Adverse Event Reporting System of the Food and Drug Administration of the United States (FAERS) of 24 major antipsychotics were extracted, cleaned, and analyzed to determine which of these drugs were correlated with weight gain. The Reported Odds Ratio (ROR) and the adjusted Reported Odds Ratio (aROR) were calculated for each antipsychotic using logistic regression models. Demographics like age, gender, and concomitant insulin use were taken into consideration for each drug.

EXPERT OPINION

Women had a statistically significant increase in weight gain reporting compared to men, while the men's group was associated with a reduced weight gain reporting in every antipsychotics in the logistic regression analyses. Out of the 24 antipsychotics included in our analysis, Aripiprazole, Brexpiprazole, Olanzapine, and Haloperidol had statistically significantly more weight increase reporting compared to the others.

Association of clinical symptoms and cardiometabolic dysregulations in patients with schizophrenia spectrum disorders

BACKGROUND

Patients with schizophrenia spectrum disorders (SSD) have a shortened life expectancy related to cardiovascular diseases. We investigated the association of cognitive, positive, and negative symptoms with cardiometabolic dysregulations in SSD patients.

METHODS

Overall, 1,119 patients from the Genetic Risk and Outcome in Psychosis (GROUP) study were included. Cognitive function, positive and negative symptoms were assessed at baseline, 3-year, and 6-year. Cardiometabolic biomarkers were measured at 3-year follow-up. We used linear and multinomial logistic regression models to test the association between cardiometabolic biomarkers and clinical trajectories and performed mediation analyzes, while adjusting for clinical and demographic confounders.

RESULTS

Cognitive performance was inversely associated with increased body mass index (mean difference [β], βhigh = -1.24, 95% CI = -2.28 to 0.20, P = 0.02) and systolic blood pressure (βmild = 2.74, 95% CI = 0.11 to 5.37, P = 0.04). The severity of positive symptoms was associated with increased glycated hemoglobin (HbA1c) levels (βlow = -2.01, 95% CI = -3.21 to -0.82, P = 0.001). Increased diastolic blood pressure (ORhigh-decreased = 1.04, 95% CI = 1.01 to 1.08, P = 0.02; ORhigh-increased = 1.04, 95% CI = 1.00 to 1.08, P = 0.048) and decreased high-density lipoprotein (OR high-increased = 6.25, 95% CI = 1.81 to 21.59, P = 0.004) were associated with more severe negative symptoms. Increased HbA1c (ORmoderate = 1.05, 95% CI = 1.01 to 1.10, P = 0.024; ORhigh = 1.08, 95% CI = 1.02 to 1.14, P = 0.006) was associated with more severe positive symptoms. These associations were not mediated by antipsychotics.

CONCLUSIONS

We showed an association between cardiometabolic dysregulations and clinical and cognitive symptoms in SSD patients. The observed associations underscore the need for early identification of patients at risk of cardiometabolic outcomes.

Correlation of Obesity and Clinical Characteristics in Drug-Naive First-Episode Patients With Schizophrenia

OBJECTIVES

This study was aimed at investigating the prevalence of obesity in drug-naive first-episode (DNFE) patients with schizophrenia and its association with metabolic parameters, psychopathological symptoms, and cognitive function.

METHODS

We collected general information on 411 DNFE schizophrenia patients and divided them into obese and nonobese groups according to body mass index (BMI). Glucolipid metabolic parameters of patients were collected. Positive and Negative Syndrome Scale was performed for assessing patients' psychopathological symptoms. Cognitive function was observed and evaluated in both groups. Pearson correlation analysis was applied to assess factors related to BMI, while we conducted multiple stepwise regression analysis for determining risk factors for obesity.

RESULTS

Obesity occurred in 60.34% of DNFE patients with schizophrenia, whereas the obese group had notably higher BMI value and waist-to-hip ratio than the nonobese group ( P < 0.05). Obese patients had markedly higher levels of blood glucose, insulin, apolipoprotein B, total triglycerides, low-density lipoprotein cholesterol, and total cholesterol versus nonobese patients ( P < 0.05). Besides, the disease severity and cognitive function were dramatically lower in the obese group. Results of multiple stepwise regression analysis demonstrated negative symptoms, low-density lipoprotein cholesterol, triglycerides, and blood glucose levels as the risk factors for comorbid obesity in DNFE patients with schizophrenia.

CONCLUSIONS

The detection rate of obesity was high in DNFE patients with schizophrenia, and there was an intrinsic association between obesity and glucolipid metabolism, clinical symptoms, and cognitive function among them. Our study will provide a theoretical foundation for the diagnosis of obesity in DNFE patients with schizophrenia and the development of effective early interventions.

Overweight or Obesity among Chinese Han People with Schizophrenia: Demographic, Clinical and Cognitive Correlations

People with schizophrenia are more likely to be afflicted by obesity or overweight compared to the general population. This study aimed to explore the incidence of overweight and obesity, clinical features and cognitive performance of Chinese Han patients with chronic schizophrenia who had overweight or obesity. We obtained data from 985 schizophrenia inpatients about overweight and obesity through body mass index (BMI). All patients were evaluated with the positive and negative syndrome scale, the Mini-mental State Examination (MMSE) and the repeated battery for evaluation of the neuropsychological status (RBANS) scale. We collected demographic and clinical data using self-reported questionnaires. We divided patients into normal weight (BMI < 24 kg/m2), overweight (24 ≤ BMI < 28 kg/m2) and obese (≥28 kg/m2) groups according to the Working Group on Obesity in China (WGOC) criteria. We compared the clinical data between the three groups and then conducted binary logistic regression and linear regression to assess variables that were significantly associated with overweight and obesity and higher BMI. Of the sample, 324 (32.9%) and 191 (19.4%) patients had overweight and obesity, respectively. Patients who had overweight and obesity were younger, had less education, had higher waist and hip circumferences, higher rates of diabetes and a higher sumPANSP score (compared with patients in the normal group, p < 0.05). There were more female patients with obesity (compared with patients in the normal and overweight groups, p < 0.05). Logistic regression analysis indicated that overweight and obesity were associated with sumPANSP (OR = 1.03, 95%CI = 1-1.061, p = 0.049) and diabetes (OR = 1.891, 95%CI = 1.255-2.849, p = 0.002). Further linear regression showed that age (B = -0.004, t = -2.83, p = 0.005), educational level (B = -0.037, t = -2.261, p = 0.024), diabetes (B = 0.133, t = 2.721, p = 0.007) and sumPANSP (B = 0.008, t = 2.552, p = 0.011) were risk factors for higher BMI. We did not find cognitive performance differences between patients with or without overweight and obesity. Overweight and obesity were associated with some demographic and clinical factors in patients with persistent schizophrenia.

Changes of neurocognitive status in patients with the first-episode psychosis after 18 months of treatment-A prospective cohort study

Neurocognitive symptoms exert the most influence on treatment outcomes over the course of schizophrenia, starting from the first-episode of psychosis (FEP) onwards. Our aim was to analyze the neurocognitive status of FEP compared to healthy controls (HC), and its change after 18 months of treatment. We performed a study in a sample of 159 patients with FEP and 100 HC. We followed the patients up for 18 months after initial assessment with a battery of neurocognitive tests. We observed statistically significant improvement in the majority of neurocognitive tests after 18 months, but several tests of specific neurocognitive domains (verbal memory, language functions, executive functions) did not show significant differences between the two assessments. The results for the majority of tests obtained from patients with FEP after 18 months of treatment showed significant deterioration compared with HC. Although our study showed significant improvement of baseline neurocognitive deficits in FEP with treatment, this varied across domains and overall performance remained below that of HC. Thus, while it seems that treatment of FEP may help to delay or restore neurocognitive deterioration, it is unclear whether specific areas of neurocognitive deterioration (e.g. verbal domain) would benefit from more time or specific treatment approaches.

The prevalence and independent influencing factors of obesity and underweight in patients with schizophrenia: a multicentre cross-sectional study

BACKGROUND

Few studies have investigated the weight of patients with schizophrenia in China.

OBJECTIVE

The aim of this study was to analyse the prevalence, clinical characteristics and influencing factors of obesity and underweight in patients with chronic schizophrenia in China.

METHODS

A total of 325 patients with schizophrenia and 172 sex- and age-matched healthy controls from the community were recruited. Socio-demographic data and laboratory measurements were collected for all subjects. Using the Positive and Negative Syndrome Scale (PANSS), we evaluated the psychiatric symptoms of patients with schizophrenia. According to the body mass index (BMI) criteria in China, BMI ≥ 28 kg/m² indicates obesity, and BMI < 18.5 kg/m² indicates underweight.

RESULTS

Of the patients with schizophrenia, 16.3% were obese, and 6.8% were underweight; 11.0% of the healthy controls were obese, and 3.5% were underweight. There was no difference between the two groups in the prevalence of obesity and underweight. After controlling for relevant variables, the obesity rate remained non significant, but the underweight rate appeared to be different. The multinomial regression analysis revealed that among the patients with schizophrenia, female sex, triglyceride level and LDL level were independent risk factors for obesity and that HDL level was an independent protective factor against obesity. In contrast, male sex and HDL level were independent risk factors for underweight.

CONCLUSION

We found that the patients with schizophrenia had an increased rate of underweight and some factors related to weight.

LEVEL OF EVIDENCE

Level V, descriptive study.

Association Between Cardiovascular Risk Factors and Cognitive Impairment in People With Schizophrenia: A Systematic Review and Meta-analysis

IMPORTANCE

Schizophrenia is associated with cognitive dysfunction and cardiovascular risk factors, including metabolic syndrome (MetS) and its constituent criteria. Cognitive dysfunction and cardiovascular risk factors can worsen cognition in the general population and may contribute to cognitive impairment in schizophrenia.

OBJECTIVE

To study the association between cognitive dysfunction and cardiovascular risk factors and cognitive impairment in individuals with schizophrenia.

DATA SOURCES

A search was conducted of Embase, Scopus, MEDLINE, PubMed, and Cochrane databases from inception to February 25, 2020, using terms that included synonyms of schizophrenia AND metabolic adversities AND cognitive function. Conference proceedings, clinical trial registries, and reference lists of relevant publications were also searched.

STUDY SELECTION

Studies were included that (1) examined cognitive functioning in patients with schizophrenia or schizoaffective disorder; (2) investigated the association of cardiovascular disease risk factors, including MetS, diabetes, obesity, overweight, obesity or overweight, hypertension, dyslipidemia, and insulin resistance with outcomes; and (3) compared cognitive performance of patients with schizophrenia/schizoaffective disorder between those with vs without cardiovascular disease risk factors.

DATA EXTRACTION AND SYNTHESIS

Extraction of data was conducted by 2 to 3 independent reviewers per article. Data were meta-analyzed using a random-effects model.

MAIN OUTCOMES AND MEASURES

The primary outcome was global cognition, defined as a test score using clinically validated measures of overall cognitive functioning.

RESULTS

Twenty-seven studies involving 10 174 individuals with schizophrenia were included. Significantly greater global cognitive deficits were present in patients with schizophrenia who had MetS (13 studies; n = 2800; effect size [ES] = 0.31; 95% CI, 0.13-0.50; P = .001), diabetes (8 studies; n = 2976; ES = 0.32; 95% CI, 0.23-0.42; P < .001), or hypertension (5 studies; n = 1899; ES = 0.21; 95% CI, 0.11-0.31; P < .001); nonsignificantly greater deficits were present in patients with obesity (8 studies; n = 2779; P = .20), overweight (8 studies; n = 2825; P = .41), and insulin resistance (1 study; n = 193; P = .18). Worse performance in specific cognitive domains was associated with cognitive dysfunction and cardiovascular risk factors regarding 5 domains in patients with diabetes (ES range, 0.23 [95% CI, 0.12-0.33] to 0.40 [95% CI, 0.20-0.61]) and 4 domains with MetS (ES range, 0.15 [95% CI, 0.03-0.28] to 0.40 [95% CI, 0.20-0.61]) and hypertension (ES range, 0.15 [95% CI, 0.04-0.26] to 0.27 [95% CI, 0.15-0.39]).

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, MetS, diabetes, and hypertension were significantly associated with global cognitive impairment in people with schizophrenia.

Sex-specific Association of Antipsychotic-induced Weight Gain and Treatment Response for Antipsychotic-Naive First Episode Schizophrenia Patients: A Prospective 8-week Longitudinal Study

BACKGROUND

Patients with antipsychotic-naïve first-episode (ANFE) schizophrenia (SZ) can help clarify many confounding factors in determining sex differences in antipsychotic drug induced weight gain and its association with symptom improvement.

METHODS

This 8-week longitudinal trial of ANFE patients with SZ enrolled 526 patients and 313 healthy controls. We evaluated bodyweight and the efficacy of antipsychotics on the Positive and Negative Syndrome Scale (PANSS) at baseline and at the end of week 8.

RESULTS

Males and females after treatment showed no sex difference in weight gain, BMI increase, and percentage of weight gain. However, at baseline, male patients had more positive symptoms than female patients, and decreases in positive symptoms, general psychopathology, and total PANSS scores were less in male than female patients. Adjusting for confounding factors using multiple linear regression confirmed that weight gain was significantly associated with these decreases in PANSS symptoms only in men not women.

CONCLUSIONS

The relationship between weight gain and symptom reduction after 8 weeks of antipsychotic treatment exists only in male patients with ANFE SZ and not in female patients.

Schizophrenic patients’ cognitive functions in relation to their metabolic profile: a cross-sectional, comparative study on an Egyptian sample

Background

Patients with schizophrenia suffer from diffuse cognitive impairment and high prevalence of cardiovascular metabolic risks, associated with poor clinical outcomes. We aimed in this study to test the presence of cognitive impairment in a sample of patients with schizophrenia, and evaluate its possible relations to patients’ metabolic profile. We recruited forty patients diagnosed with schizophrenia and their matched controls from the inpatient departments and outpatient services from January to December 2016. Schizophrenia diagnosis was confirmed by the ICD10 criteria checklist. Symptoms profile and severity were assessed by the Positive and Negative Syndrome Scale. Cognitive profile was assessed through (1) Trail Making Test, Parts A and B and (2) Wechsler Memory Scale-Revised Visual Reproduction Test. Metabolic profile was assessed by measuring the body mass index, fasting blood glucose, and lipid profile. SPSS (V. 22.0, IBM Corp., USA, 2013) was used for data analysis.

Results

The patients group had a significantly higher means in the speed of processing, executive function, attention, and working memory scores on TMT-A (p = 0.0), TMT-B (p = 0.00), and WMS-R (p = 0.029) and significantly higher FBG levels (p = 0.00). Correlation studies showed that the increase in patients’ age, illness duration, treatments, number of hospitalizations, number of episodes and of ECT sessions received, symptoms severity, and deficits in cognitive function scores was associated with higher BMI and FBG.

Conclusions

Patients with schizophrenia have a higher prevalence of cognitive impairment and vascular risk factors than the general population. Close monitoring and early management of these risk factors can promote better cognitive abilities and overall functions.

A higher body mass index in Chinese inpatients with chronic schizophrenia is associated with elevated plasma orexin-A levels and fewer negative symptoms

Objective: Orexin-A is involved in numerous physiological functions, such as feeding behavior and energy balance. Yet, the associations among the orexin system, weight changes and the clinical symptoms of schizophrenia patients remain uncertain, especially in inpatients with chronic schizophrenia (CS). The purpose of this study was to investigate the relationship between the orexin-A levels, body mass index (BMI) and clinical symptoms of CS inpatients.Methods: Altogether, 324 inpatients were enrolled in our study. The clinical symptoms of all inpatients were measured using a 30-item Positive and Negative Syndrome Scale (PANSS), and then we calculated the BMI of each subject and tested the orexin-A levels by ELISA methods.Results: The orexin-A levels of the CS inpatients in the obesity group (1.24 ± 1.45 ng/ml, n = 52) were significantly higher than those in the non-overweight group (0.85 ± 1.18 ng/ml, n = 176) and the overweight group (0.97 ± 1.15 ng/ml, n = 96). Spearman's correlation analysis showed that higher BMIs were associated with higher plasma orexin-A levels and fewer negative symptoms. Furthermore, the multiple regression analysis indicated that the orexin-A level could be a contributor to BMI (F = 30.21, p < 0.001). However, there was no correlation between plasma orexin-A concentrations and clinical symptoms in our research.Conclusion: A higher plasma orexin-A level may be a factor influencing the BMI of inpatients with CS, and fewer negative symptoms seem to be correlated with higher BMI, but the causality among BMI, orexin-A and clinical symptoms of schizophrenia requires further clinical research.

Sex differences in the association of body mass index with symptoms and cognitive deficits in Chinese patients with chronic schizophrenia

Accumulating studies have revealed gender differences in many aspects of schizophrenia (SZ), including obesity and cognitive function. The relationship between obesity and cognitive impairment in SZ has been studied before; however, the results are inconsistent. This study was designed to examine the sex differences in the relationship between body mass index (BMI) and cognitive deficits in Chinese patients with chronic SZ, which have not been investigated yet. 176 chronic patients with SZ (male/female = 108/68) and 200 controls (male/female = 120/80) were enrolled to compare the sex differences in cognitive functions measured by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), BMI, and their associations. The clinical symptoms were evaluated using the positive and negative syndrome scales (PANSS). Our results showed that male patients had lower BMI and more negative symptoms but fewer positive symptoms than female patients (all p < 0.05). However, there was no significant sex difference in RBANS scores. In male patients, BMI was correlated with age of onset, PANSS general psychopathology, total score, negative symptom, together with RBANS language, visuospatial/construction, and attention. Further regression analysis showed that in male patients, BMI was significantly associated with RBANS language, PANSS general psychopathology, PANSS total score, and age of onset, with adjusted R² = 0.22. These findings revealed significant sex differences in BMI, cognitive dysfunctions and their association in SZ. Nonetheless, these results should only be considered as preliminary because of the cross-sectional design, which will deserve further replication in first-episode patients using a prospective longitudinal design.

Obesity in Chinese patients with chronic schizophrenia: Prevalence, clinical correlates and relationship with cognitive deficits

The prevalence of obesity in schizophrenia patients is high, especially in chronic and medicated patients. Few studies have explored the relationships between obesity, cognition and clinical correlates in patients with schizophrenia. This study was designed to assess the prevalence and clinical correlates of obesity and its relationship to cognitive impairment in Chinese patients with schizophrenia. We recruited 633 inpatients and collected clinical, demographic data and lipid parameters. The Positive and Negative Syndrome Scale (PANSS) and its five-factor model were adopted for psychopathological symptoms. The prevalence of comorbid obesity in schizophrenia patients was 16.4%. The plasma levels of glucose, triglyceride, low density lipoprotein (LDL), apolipoprotein B, and cholesterol were higher, but high density lipoprotein (HDL) levels were lower in obese patients than those in non-obese patients (all p < 0.05). Furthermore, obese patients had lower PANSS negative symptom, cognitive factor and total scores than non-obese patients (all p < 0.05). Correlation analysis showed a significant correlation between BMI and the following variables: age, marriage, gender, negative symptoms, general psychopathological symptoms, cognitive factor, PANSS total score, glucose, triglycerides, HDL, LDL, cholesterol and apolipoprotein B (all p < 0.05). Further multiple regression showed that PANSS cognitive factor, PANSS total score, and triglyceride were important independent predictors of obesity. Our results indicate a high prevalence of obesity in Chinese patients with chronic schizophrenia. Multiple demographics, clinical variables, and lipid parameters are associated with obesity in schizophrenia. Moreover, obesity appears to be a protective factor for psychological symptoms. However, not having objective assessments for cognition in this study is a limitation.

Shared pathways for neuroprogression and somatoprogression in neuropsychiatric disorders

Activated immune-inflammatory, oxidative and nitrosative stress (IO&NS) pathways and consequent mitochondrial aberrations are involved in the pathophysiology of psychiatric disorders including major depression, bipolar disorder and schizophrenia. They offer independent and shared contributions to pathways underpinning medical comorbidities including insulin resistance, metabolic syndrome, obesity and cardiovascular disease - herein conceptualized as somatoprogression. This narrative review of human studies aims to summarize relationships between IO&NS pathways, neuroprogression and somatoprogression. Activated IO&NS pathways, implicated in the neuroprogression of psychiatric disorders, affect the pathogenesis of comorbidities including insulin resistance, dyslipidaemia, obesity and hypertension, and by inference, metabolic syndrome. These conditions activate IO&NS pathways, exacerbating neuroprogression in psychiatric disorders. The processes whereby proinflammatory cytokines, nitrosative and endoplasmic reticulum stress, NADPH oxidase isoforms, PPARγ inactivation, SIRT1 deficiency and intracellular signalling pathways impact lipid metabolism and storage are considered. Through associations between body mass index, chronic neuroinflammation and FTO expression, activation of IO&NS pathways arising from somatoprogression may contribute to neuroprogression. Early evidence highlights the potential of adjuvants targeting IO&NS pathways for treating somatoprogression and neuroprogression.

Relationship between changes in metabolic syndrome constituent components over 12 months of treatment and cognitive performance in first-episode schizophrenia

Few studies have investigated the longitudinal effects of treatment-emergent metabolic syndrome changes on cognitive performance in first-episode psychosis. The aim of the present study was to determine the associations between changes in metabolic syndrome constituent component over 12 months of treatment and end-point cognitive performance in schizophrenia spectrum disorders. This single site-cohort study included 72 minimally treated or antipsychotic-naïve first-episode patients. Cognitive performance was evaluated using the MATRICS Consensus Cognitive Battery (MCCB). Our primary objective of interest was the relationship between metabolic syndrome constituent component changes over 12 months of treatment and end-point cognitive performance. Secondary objectives included investigating whether this relationship was affected by age, sex, antipsychotic dose, treatment duration and substance use. Weight gain predicted better overall cognition (p = 0.02) at end-point, adjusting for age, sex, substance use, baseline cognitive score and BMI, modal antipsychotic dose and treatment duration. Weight loss (p = 0.04) and substance use (p = 0.01) were both associated with poorer working memory performance at end-point. Low baseline BMI showed differential effects on end-point working memory performance in substance users (unfavorable) compared to non-users (favorable) (p < 0.05). In conclusion, weight gain over the course of antipsychotic treatment is associated with better overall cognitive performance and the working memory domain in first-episode schizophrenia spectrum disorder patients. In contrast, low baseline BMI may represent an unfavorable marker in substance users, who demonstrated weight loss compared to non-users.

Naltrexone and Bupropion Combination Treatment for Smoking Cessation and Weight Loss in Patients With Schizophrenia

Objective: The rates of obesity and cigarette smoking are much higher in patients with schizophrenia compared to the general population. This study was to examine whether naltrexone and bupropion combination treatment can help weight loss and smoking cessation in patients with schizophrenia.

Methods: Obese male schizophrenia patients with current cigarette smoking were randomized to receive adjunctive naltrexone (25 mg/day) and bupropion (300 mg/day) combination or placebo for 24 weeks. Twenty-two patients were enrolled in the study, and 21 patients completed the study (11 in the treatment group, and 10 in the placebo group). Body weight, body mass index (BMI), fasting lipids, smoking urge, expired carbon monoxide (CO) level and cigarettes smoked per week were measured at baseline and week 24.

Results: There was no significant difference between two groups in changes in weight, BMI, fasting lipids, or cigarette smoking measures (p's > 0.05)

Conclusion: Naltrexone and bupropion combination treatment didn't show weight loss or smoking cessation effect in patients with schizophrenia in this pilot study.Implications for future studies were discussed.

ClinicalTrials.gov identifier: NCT02736474.

Cognitive dysfunction and metabolic comorbidities in mood disorders: A repurposing opportunity for glucagon-like peptide 1 receptor agonists?

Major depressive disorder and bipolar disorder are highly prevalent and disabling conditions. Cognition is considered a core domain of their psychopathology and a principle mediator of psychosocial impairment, disproportionately accounting for overall illness-associated costs. There are few interventions with replicated evidence of efficacy in treating cognitive deficits in mood disorders. Evidence also indicates that cognitive deficits are associated with obesity and involve significant impairment across multiple domains. Conversely, weight-loss interventions, such as physical exercise and bariatric surgery, have been shown to beneficially affect cognitive function. This convergent phenomenology suggests that currently available agents that target metabolic systems may also be capable of mitigating deficits in cognitive functions, and are, therefore, candidates for repurposing. The incretin glucagon-like peptide-1 (GLP-1) is a hormone secreted by intestinal epithelial cells. GLP-1 receptors (GLP-1R) are widely expressed in the central nervous system. Activation of GLP-1R leads to facilitation of glucose utilization and antiapoptotic effects in various organs. Pre-clinical trials have demonstrated significant neuroprotective effects of GLP-1, including protection from cell death, promotion of neuronal differentiation and proliferation; and facilitation of long-term potentiation. Liraglutide is a GLP-1R agonist that has been approved for the treatment of type 2 diabetes mellitus and obesity. Convergent preclinical and clinical evidence, including a proof-of-concept pilot study from group, has suggested that liraglutide may improve objective measures of cognitive function in adults with mood disorders. The safety and availability of GLP-1R agonists indicate that they are promising candidates for repurposing, and that they may be viable therapeutic options for mood disorders. This article is part of the Special Issue entitled 'Metabolic Impairment as Risk Factors for Neurodegenerative Disorders.'

The relationship between the alterations in metabolite levels in the dorsolateral prefrontal cortex and clinical symptoms of patients with first-episode schizophrenia: a one year follow-up study

Background

Reduced brain metabolites such as N-acetyl-aspartate (NAA), glutamate (Glx), Choline (Cho) and myo-inositol (MI) have been repeatedly found in first-episode schizophrenia (FES) and suggest neuronal loss or dysfunction. However, the potential relationship between the metabolite level and the clinical symptoms or the recovery of FES remained unclear.

Objectives

This study aimed to investigate the correlation between the alterations in dorsolateral prefrontal cortex (DLPFC) metabolite levels of patients with first-episode schizophrenia (FES) and the changes in clinical symptoms after one year treatment.

Materials and Methods

FES patients underwent 1H-MRS scan twice: one time at the baseline and the other one year later, while the healthy group patients underwent only once at the baseline time. The symptom severity of patients was measured by PANSS.

Principal Observations

An increase in the NAA/Cr level was detected in the left DLPFC of patients with FES. The change in the NAA/Cr level was significantly correlated with the alteration in their PANSS-P score. The Cho/Cr levels on both sides of DLPFC in patients with FES were lower compared with the healthy controls both at the baseline and after the treatment. The NAA/Cr and MI/Cr levels in the right DLPFC were decreased after the treatment.

Conclusions

(1) the depletion of NAA in left DLPFC might be a state characteristic; (2) the Cho/Cr level might be the potential endophenotype of schizophrenia; (3) the decrease of NAA/Cr and MI/Cr level in right DLPFC might be due to the development of schizophrenia.

Relationship of Handgrip Strength and Body Mass Index With Cognitive Function in Patients With Schizophrenia

Background: The relationship between muscle strength and cognition in schizophrenia has not been well studied. We investigated the potential relationship of handgrip strength (HGS) score and body mass index (BMI) with cognitive function in patients with schizophrenia. Methods: Participants included 153 patients with schizophrenia (age: 36.9 ± 9.4 years; 82 males) and 328 healthy controls (age: 36.4 ± 10.7 years; 150 males), matched for age, sex, and ethnicity (Japanese). HGS was measured using a digital handgrip dynamometer. Cognitive function was evaluated using the Brief Assessment of Cognition in Schizophrenia (BACS) test. A two-way multivariate analysis of covariance was used to compare HGS scores between the patient and control groups. Multiple regression analyses of BACS scores were performed in the patient and control groups using HGS and BMI scores as independent variables. Results: In the intergroup comparison, significantly lower HGS scores were observed in patients with schizophrenia than in healthy controls (p < 0.05, corrected). In the patient group, there was a significantly positive correlation between HGS scores and BACS composite score (male, p = 0.0014; female, p = 0.0051). However, BMI scores were significantly negatively correlated with the BACS composite score (male, p = 0.0022; female, p = 0.018). Furthermore, the ratio of HGS/BMI was significantly positively correlated with the BACS composite score in the patient group (p = 0.00000018). Conclusions: Cognitive function in patients with schizophrenia is correlated positively with HGS and negatively with BMI. HGS/BMI may thus be a good index for cognitive performance in schizophrenia.

The relationship between moderate-to-vigorous physical activity and executive function among individuals with schizophrenia: differences by illness duration

OBJECTIVE

Schizophrenia is a chronic mental illness characterized by positive and negative symptoms. Cognitive impairment continues to be a core and consistent deficit. Previous studies have shown that physical activity (PA) is positively associated with cognitive performance. Thus, it may play a supportive role in mitigating cognitive impairments among individuals with schizophrenia. The aim of this study was to analyze the relationship between moderate-to-vigorous physical activity (MVPA) and executive function among adults with schizophrenia.

METHODS

The weekly amount of MVPA (assessed using accelerometers) and executive function (as per Brief Neurocognitive Assessment for Schizophrenia) of 78 adults with schizophrenia (mean [SD] age 42.4 [11.4] years; illness duration 17.0 [11.0] years; 58.2% male) were assessed in this cross-sectional study. Pearson correlations were calculated, followed by a linear regression. Participants were first analyzed together and then dichotomized on the basis of illness duration.

RESULTS

There was no significant association between MVPA and executive function, independent of the duration of illness. For individuals with < 15 years of illness, there was a significant association between weekly MVPA and working memory performance.

CONCLUSION

PA appears to be associated with executive function in some, but not all, individuals with schizophrenia.

The prevalence, risk factors and clinical correlates of obesity in Chinese patients with schizophrenia

Obesity is a common comorbidity in schizophrenia. Few studies have addressed obesity in Chinese schizophrenia patients. The aims of this current study were to evaluate the prevalence, risk factors and clinical correlates of obesity in Chinese patients with schizophrenia. A total of 206 patients were recruited from a hospital in Beijing. Their clinical and anthropometric data together with plasma glucose and lipid parameters were collected. Positive and Negative Syndrome Scale (PANSS) was rated for all patients. Overall, 43 (20.9%) patients were obese and 67 (32.5%) were overweight. The obese patients had significantly higher glucose levels, triglyceride levels than non-obese patients. Females and patients with type 2 diabetes mellitus had increased risk for obesity. Correlation analysis showed that BMI was associated with sex, education levels, negative symptoms, total PANSS score, triglyceride levels and type 2 diabetes mellitus. Further stepwise regression analysis showed that sex, type 2 diabetes, education level, triglyceride and amount of smoking/day were significant predictors for obesity. Our study showed that the prevalence of obesity in Chinese patients with schizophrenia is higher than that in the general population. Some demographic and clinical variables are risk factors for obesity in schizophrenia.

Relationship Between Objectively Measured Sedentary Behavior and Cognitive Performance in Patients With Schizophrenia Vs Controls

OBJECTIVE

Sedentary behavior (SB) is associated with poor cognitive performance in the general population. Although people with schizophrenia are highly sedentary and experience marked cognitive impairments, no study has investigated the relationship between SB and cognition in people with schizophrenia.

METHODS

A total of 199 inpatients with schizophrenia (mean [SD] age 44.0 [9.9] years, 61.3% male, mean [SD] illness duration 23.8 [6.5]) and 60 age and sex matched controls were recruited. Sedentary behavior and physical activity (PA) were captured for 7 consecutive days with an accelerometer. Cognitive performance was assessed using the Vienna Test System, and the Grooved Pegboard Test. Multivariate regression analyses adjusting for important confounders including positive and negative symptoms, illness duration, medication, and PA were conducted.

RESULTS

The 199 patients with schizophrenia engaged in significantly more SB vs controls (581.1 (SD 127.6) vs 336.4 (SD 107.9) min per day, P < .001) and performed worse in all cognitive performance measures (all P < .001). Compared to patients with high levels of SB (n = 89), patients with lower levels of SB (n = 110) had significantly (P < .05) better motor reaction time and cognitive processing. In the fully adjusted multivariate analysis, SB was independently associated with slower motor reaction time (β = .162, P < .05) but not other cognitive outcomes. Lower levels of PA were independently associated with worse attention and processing speed (P < .05).

CONCLUSION

Our data suggest that higher levels of sedentary behavior and physical inactivity are independently associated with worse performance across several cognitive domains. Interventions targeting reductions in SB and increased PA should be explored.

The relationship between cognitive impairment in schizophrenia and metabolic syndrome: a systematic review and meta-analysis

BACKGROUND

Individuals with schizophrenia are at greater risk for metabolic syndrome (MetS) which is associated with cognitive deficits in the general population. MetS might be potentially an important contributing factor to cognitive impairment in schizophrenia.

METHOD

In the current systematic review and meta-analysis, the findings of 18 studies investigating the association between MetS (and its components) with cognitive impairment in schizophrenia are reviewed.

RESULTS

Co-morbidity of MetS (d = 0.28) and diabetes mellitus (d = 0.28) were both associated with more severe cognitive deficits in schizophrenia. There was also evidence for a significant relationship between cognitive impairment in schizophrenia and each of the components of MetS including hypertension, dyslipidemia, abdominal obesity and diabetes.

CONCLUSIONS

MetS is significantly associated with cognitive impairment in schizophrenia and can potentially contribute to functional decline observed in some patients with schizophrenia throughout the course of illness.

The Obesity-Impulsivity Axis: Potential Metabolic Interventions in Chronic Psychiatric Patients

Pathological impulsivity is encountered in a broad range of psychiatric conditions and is thought to be a risk factor for aggression directed against oneself or others. Recently, a strong association was found between impulsivity and obesity which may explain the high prevalence of metabolic disorders in individuals with mental illness even in the absence of exposure to psychotropic drugs. As the overlapping neurobiology of impulsivity and obesity is being unraveled, the question asked louder and louder is whether they should be treated concomitantly. The treatment of obesity and metabolic dysregulations in chronic psychiatric patients is currently underutilized and often initiated late, making correction more difficult to achieve. Addressing obesity and metabolic dysfunction in a preventive manner may not only lower morbidity and mortality but also the excessive impulsivity, decreasing the risk for aggression. In this review, we take a look beyond psychopharmacological interventions and discuss dietary and physical therapy approaches.

Revisiting the International Physical Activity Questionnaire (IPAQ): Assessing physical activity among individuals with schizophrenia

BACKGROUND

Individuals with schizophrenia tend to have low levels of physical activity (PA) which contributes to high rates of physical comorbidities. Valid and reliable methods of assessing PA are essential for advancing health research. Ten years after initial validation of the Short-Form International Physical Activity Questionnaire (IPAQ), this study expands on the initial validation study by examining retest reliability over a 4-week period, assessing validity with a larger sample, and comparing validity of the IPAQ to a 24-hour recall alternative.

METHODS

Participants completed the IPAQ at baseline and 4weeks later, along with a 24-hour PA recall at week 4. At week 3 participants wore waist accelerometers for 7days. Spearman's correlation coefficients and Bland-Altman plots were calculated based on weekly minutes of moderate to vigorous PA (MVPA).

RESULTS

Test-retest reliability for the self-administered IPAQ was ρ=0.47, p<0.001 for MVPA. Correlation between IPAQ assessment and accelerometer-determined MVPA was ρ=0.30, p=0.003. The 24-hour recall correlated significantly with MVPA on the previous day ρ=0.27, p=0.012. A Bland-Altman plot indicated the IPAQ-SF underreported by -119.2min (-72%) on average compared to accelerometry (95% limits of agreement -1017.1 to 778.7min, -292% to 147%).

CONCLUSION

Compared to previous IPAQ validation work in this population, criterion validity was similar, but reliability was lower over a 4-week period. MVPA criterion validity of the 24-hour recall was comparable to the 7-day self-report IPAQ. Findings further support that the IPAQ is a suitable assessment tool for epidemiological studies. Objective measures of physical activity are recommended for intervention assessment.

Sex Differences in Body Mass Index and Obesity in Chinese Patients With Chronic Schizophrenia

Sex differences in schizophrenia have been well recognized. However, sex differences in obesity associated with antipsychotics have received little systematic study. This study was conducted to compare sex difference effects of antipsychotics and related risk factors on obesity and body mass index (BMI) in Chinese patients with schizophrenia. A total of 204 inpatients with chronic schizophrenia (males/females = 140/66) were recruited. Demographic and clinical data were collected, and serum glucose and lipid levels were measured. The Positive and Negative Syndrome Scale (PANSS) was used to assess patients' psychopathology. The prevalence of obesity in female patients (21/66, 31.82%) was approximately 2 times that of male patients (22/140, 15.83%; P < 0.001) and women also had higher BMI than men (25.49 ± 4.42 kg/m versus 23.95 ± 3.67 kg/m; P < 0.005). Regression analyses showed that obesity was associated with type 2 diabetes (P < 0.05) and triglycerides (P < 0.05) in women, and limited to triglyceride in men (P < 0.01). Further correlation analysis showed that BMI was associated with the PANSS negative symptom subscore (P < 0.001) and the PANSS total score (P < 0.01) in men. In addition, women had higher low-density lipoprotein plasma levels than men. Our findings suggest that there are significant sex differences in bodyweight and obesity in chronic medicated patients with schizophrenia, with worse lipid metabolic dysfunction in female patients.

Cardiometabolic health, prescribed antipsychotics and health-related quality of life in people with schizophrenia-spectrum disorders: a cross-sectional study

BACKGROUND

People with schizophrenia-spectrum disorders (SSD) often have high levels of obesity and poor cardiometabolic health. Certain types of antipsychotics have been shown to contribute towards weight gain and there is some equivocal evidence that obesity is related to poor health-related quality of life (HRQoL) in people with SSD. It is also still uncertain if antipsychotic polypharmacy/higher doses of antipsychotics are linked with HRQoL and/or increased risk of obesity/Cardiovascular Disease (CVD). Therefore, this study aimed to examine potential relationships between prescribed antipsychotic medication regimens, cardiometabolic health risks and HRQoL in community-based Chinese people with SSD.

METHOD

This cross-sectional study reports the results of baseline measurements of a random sample of patients in an ongoing controlled trial of physical health intervention for people with severe mental illness. Data from these randomly-selected participants (n = 82) were analysed to calculate 10-year CVD relative-risk (using QRISK®2 score), estimate the prevalence of metabolic syndrome and contextualize patients' prescribed antipsychotics (types, combinations and Daily Defined Dose equivalent). Patients self-reported their HRQoL (SF12v2) and their obesity condition was assessed by waist-circumference and Body Mass Index (BMI).

RESULTS

Two-thirds of patients had a BMI ≥23 kg/m², almost half were centrally obese and 29% met the criteria for metabolic syndrome. The individual relative-risk of CVD ranged from 0.62 to 15, and 13% had a moderate-to-high 10-year CVD risk score. Regression models showed that lower physical HRQoL was predicted by higher BMI and lower mental HRQoL. Higher Defined Daily Dose, clozapine, younger age and male gender were found to explain 40% of the variance in CVD relative risk.

CONCLUSION

The findings indicate that cardiometabolic health risks in people with SSD may be more common than those reported in the general Hong Kong population. The results also provide further support for the need to consider antipsychotic polypharmacy and higher doses of antipsychotics as factors that may contribute towards cardiometabolic risk in Chinese patients with SSD. Clinicians in Hong Kong should consider using routine CVD risk screening, and be aware that younger male patients who are taking clozapine and prescribed higher Defined Daily Dose seem to have the highest relative-risk of CVD.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02453217 . Prospectively registered on 19^th May 2015.

Abdominal obesity is associated with impaired cognitive function in euthymic bipolar individuals

OBJECTIVES

Overweight/obesity has been implicated to play a role in cognitive deficits in bipolar disorder (BD). This study aims to identify the relationship between body fat distribution and different domains of cognition in BD during euthymia.

METHODS

A sample of 100 euthymic individuals with BD was measured with a cognitive test battery (i.e., Trail Making Test-A-B/TM-A/B, d2 Test of Attention, Stroop test, California Verbal Learning Test/CVLT) and an anthropometric measures set (body mass index, waist circumference, hip circumference, waist-to-hip-ratio, waist-to-height-ratio, and lipometry). Patient data were compared with a healthy control group (n = 64).

RESULTS

Results show that overweight patients with BD exhibit lower performance in the TMT-A/B as well as in the free recall performance of the CVLT compared to normal-weight patients with BD and controls. In bipolar individuals, (abdominal) obesity was significantly associated with a poor cognitive performance. In bipolar females, associations with measures of verbal learning and memory were found; in bipolar males, associations with poor performance in the TMT-A/B and in the Stroop interference task were demonstrated. In controls, no associations were found.

CONCLUSIONS

There are several possible pathways moderating the association between obesity and cognition in BD. Anthropometric and lipometry data underline the substantial mediating impact of body fat distribution on cognition in BD.

Neurodevelopmental origin of cognitive impairment in schizophrenia

Cognitive impairment is a common feature of schizophrenia; however, its origin remains controversial. Neurodevelopmental abnormalities clearly play a role in pre-morbid cognitive dysfunction in schizophrenia, yet many authors believe that schizophrenia is characterized by illness-related cognitive decline before and after onset of the psychosis that can be the result of neurodegenerative changes. The main reasons behinds such arguments include, first, the evidence showing that effect sizes of the cognitive deficits in subjects who develop adult schizophrenia gradually increase in the first two decades of life and, second, the fact that there is functional decline in many patients with schizophrenia over the years. In this Editorial, I argue that current evidence suggests that illness-related cognitive impairment is neurodevelopmental in origin and characterized by slower gain (developmental lag) but not cognitive decline continuing throughout the first two decades of life. I introduce a model suggesting that neurodevelopmental abnormality can in fact explain the course of cognitive dysfunction and variations in the trajectory of functional decline throughout the life in individuals with schizophrenia. In this model, the severity of underlying neurodevelopmental abnormality determines the age that cognitive deficits first become apparent and contributes to the cognitive reserve of the individual. Interaction of neurodevelopmental abnormality with clinical symptoms, especially negative symptoms and aging, vascular changes, psychological and iatrogenic factors contributes to the heterogeneity of the functional trajectory observed in this disorder.

Aerobic fitness and body mass index in individuals with schizophrenia: Implications for neurocognition and daily functioning

Previous reports indicate that among healthy individuals low aerobic fitness (AF) and high body-mass index (BMI) predict poor neurocognition and daily-functioning. It is unknown whether these associations extend to disorders characterized by poor neurocognition, such as schizophrenia. Therefore, we compared AF and BMI in individuals with schizophrenia and non-clinical controls, and then within the schizophrenia group we examined the links between AF, BMI, neurocognition and daily-functioning. Thirty-two individuals with schizophrenia and 64 gender- and age-matched controls completed assessments of AF (indexed by VO2max) and BMI. The former also completed measures of neurocognition, daily-functioning and physical activity. The schizophrenia group displayed significantly lower AF and higher BMI. In the schizophrenia group, AF was significantly correlated with overall neurocognition (r=0.57), along with executive functioning, working memory, social cognition, and processing speed. A hierarchical regression analysis indicated that AF accounted for 22% of the neurocognition variance. Furthermore, AF was significantly correlated with overall daily-functioning (r=0.46). In contrast, BMI displayed significant inverse correlations with neurocognition, but no associations to daily-functioning. AF was significantly correlated physical activity. The authors discuss the potential use of AF-enhancing interventions to improve neurocognitive and daily-functioning in schizophrenia, along with putative neurobiological mechanisms underlying these links, including Brain-Derived Neurotrophic Factor.

Intelligence and obesity: which way does the causal direction go?

PURPOSE OF REVIEW

The negative association between intelligence and obesity has been well established, but the direction of causality is unclear. The present review surveys the recent studies on the topic with both cross-sectional and longitudinal data in an attempt to establish causality.

RECENT FINDINGS

Most studies in the area employ cross-sectional data and conclude (without empirical justification) that obesity causes intellectual impairment. The few studies that employ prospectively longitudinal data, however, uniformly conclude that lower intelligence leads to BMI gains and obesity. A close examination of three such studies, from three different nations (Sweden, New Zealand, and the UK), leaves little doubt that the causality runs from low intelligence to obesity.

SUMMARY

The conclusion in previous studies that obesity impairs cognitive function stems from improper interpretation of a negative association between intelligence and obesity from cross-sectional studies. Results from the analyses of high-quality, population-based, prospectively longitudinal data firmly establish that low intelligence increases the chances of obesity.

Homozygous Deletion of Glutathione Peroxidase 1 and Aldehyde Dehydrogenase 1a1 Genes Is Not Associated with Schizophrenia-Like Behavior in Mice

Much evidence suggests that oxidative stress plays a role in schizophrenia pathogenesis. Major oxidative stress sources include hydrogen peroxide and biogenic aldehydes that are mainly cleared in vivo by glutathione peroxidase (GPX) and aldehyde dehydrogenase (ALDH), respectively. Both enzymes are richly expressed in brain. Schizophrenia patients have significantly increased plasma levels of malondialdehyde and glutathione, combined with decreased GPX activity and ALDH1 mRNA levels in the ventral tegmental area. Absence of Aldh1a1 (murine homolog of ALDH1) gene causes increased basal extracellular dopamine concentrations, a common characteristic of schizophrenia. Studies investigating association between gene polymorphisms of GPX1 (the most abundant form of GPX) or ALDH1A1 with schizophrenia also have not clearly demonstrated whether ALDH1A1 or GPX1 is involved in pathogenesis of schizophrenia. To investigate possible contributions of ALDH and GPX to pathological behaviors associated with schizophrenia, we generated mice with both Aldh1a1 and Gpx1 gene deletions (KO). Aldh1a1/Gpx1 KO and wild type (WT) mice had similar number of novel entry and alteration in Y-maze test, suggesting no cognition deficit in KO. Furthermore, KO and WT displayed similar social interaction and novelty preferences in three chambered tests. Overall, KO and WT had similar activity levels, as indicated by their entries in the Y-maze and sociability tests. Furthermore both genotypes buried a similar percentage of marbles in a 30 min marble-burying task. In summary, homozygous deletion of Gpx1 and Aldh1a1 genes was not associated with schizophrenia-like behavioral phenotypes including anxiety, hyperactivity, cognitive deficit or social disability. Our findings suggest that constitutive absence of these genes alone is unlikely to give rise to common behavioral schizophrenia symptoms. However, these mice may be highly sensitive to oxidative challenges during critical stages of prenatal or juvenile brain development.

Molecular hydrogen: an overview of its neurobiological effects and therapeutic potential for bipolar disorder and schizophrenia

Hydrogen gas is a bioactive molecule that has a diversity of effects, including anti-apoptotic, anti-inflammatory and anti-oxidative properties; these overlap with the process of neuroprogression in major psychiatric disorders. Specifically, both bipolar disorder and schizophrenia are associated with increased oxidative and inflammatory stress. Moreover, lithium which is commonly administered for treating bipolar disorder has effects on oxidative stress and apoptotic pathways, as do valproate and some atypical antipsychotics for treating schizophrenia. Molecular hydrogen has been studied pre-clinically in animal models for the treatment of some medical conditions including hypoxia and neurodegenerative disorders, and there are intriguing clinical findings in neurological disorders including Parkinson’s disease. Therefore, it is hypothesized that administration of hydrogen molecule may have potential as a novel therapy for bipolar disorder, schizophrenia, and other concurrent disorders characterized by oxidative, inflammatory and apoptotic dysregulation.