Association between antipsychotic treatment and leptin levels across multiple psychiatric populations: An updated meta-analysis

Psychotropic drugs, eating behaviour and weight gain

PURPOSE OF REVIEW

Psychotropic drug related weight gain is a common side-effect of significant concern to both clinicians and patients. Recent studies and treatment guidelines strongly support taking preventive and early treatment approaches to psychotropic drug-related weight gain (PDWG). Arguably the main pathway that PDWG occurs is via changes in eating behaviour leading to increased caloric intake.

RECENT FINDINGS

Systematic reviews and meta-analyses have provided good data on the nature and prevalence of alterations in eating behaviour with psychotropic treatment including increased hunger, night eating and binge eating. These changes are unsurprisingly more prominent with agents like olanzapine and clozapine that have high propensity to cause weight gain.

SUMMARY

Altered eating behaviour can serve as an earlier measure of the risk of weight gain and can be examined easily in clinical practice. Detecting these changes can enable earlier action in terms of switching treatments and starting pharmacological and nonpharmacological preventive strategies.

Antipsychotic-Induced Weight Gain in Severe Mental Illness: Risk Factors and Special Considerations

PURPOSE OF REVIEW

Weight gain is a disconcerting issue experienced by patients treated with antipsychotics (APs). This review summarizes current knowledge on the prevalence, etiology, and risk factors for antipsychotic-induced weight gain (AIWG), and evidence for interventions, including special considerations.

RECENT FINDINGS

Predisposing risk factors for AIWG include lack of prior AP exposure, sex, and age. AP dose and duration of exposure are additional treatment-related factors that may contribute to this issue. Among current approaches to target AIWG, metformin has the most evidence to support its use, and this is increasingly reflected in clinical guidelines. While lifestyle approaches are recommended, cost-effectiveness and scalability represent limitations. More research is needed to identify newer treatment options and inform clinical recommendations for AIWG. Concerns around scope of practice in psychiatry to address AIWG and related comorbidities will require enhanced training opportunities and interdisciplinary collaborations, as well as updated position statements/practice guidelines emphasizing prevention.

A Marked Low-Grade Inflammation and a Significant Deterioration in Metabolic Status in First-Episode Schizophrenia: A Five-Year Follow-Up Study

The objective of this study was to evaluate how schizophrenia spectrum disorders and applied long-term (5.1 years) antipsychotic (AP) treatment affect the serum level of acylcarnitines (ACs), cytokines and metabolic biomarkers and to characterize the dynamics of inflammatory and metabolic changes in the early course of the disorder. A total of 112 adults participated in the study (54 patients with first-episode psychosis (FEP) and 58 control subjects). Biomolecule profiles were measured at the onset of first-episode psychosis and 0.6 years and 5.1 years after the initiation of APs. The results of the present study confirmed that specific metabolic-inflammatory imbalance characterizes AP-naïve patients. Short-term (0.6-years) AP treatment has a favourable effect on psychotic symptoms, as well as the recovery of metabolic flexibility and resolution of low-level inflammation. However, 5.1 years of AP treatment resulted in weight gain and increased serum levels of interleukin (IL)-2, IL-4, IL-6, IL-10, interferon-γ, hexoses, acetylcarnitine, short-chain ACs (C3, C4) and long-chain ACs (C16:2, C18:1, C18:2). In conclusion, despite the improvement in psychotic symptoms, 5.1 years of AP treatment was accompanied by a pronounced metabolic-inflammatory imbalance, which was confirmed by the presence of enhanced pro-inflammatory activity and increased obesity with changes in the metabolism of carbohydrates, lipids, and their metabolites.

Assessment of vitamin D levels and adipokines mediated obesity among psychiatric patients on treatment and treatment naïve: A comparative cross-sectional study

Background and aims

Antipsychotic treatment may contribute to low vitamin D levels and have impact on direct anti-inflammatory activity such as adiponectin activity and indirect proinflammatory activity such as leptin and resistin activity. However, vitamin D levels and adipokines mediated effect on weight gain and increased adiposity are not well evaluated. This study, therefore, assessed vitamin D and adipokines-mediated obesity among Ghanaian psychiatric patients.

Methods

This comparative cross-sectional study was conducted at psychiatric unit of Komfo Anokye Teaching Hospital, Kumasi, Ghana. Anthropometric measurements, sociodemographic and previous medical history were taken from 300 antipsychotics treatment naïve and active patients. Obesity was classified using World Health Organization (WHO) body mass index (BMI)-specific cut-offs. Blood samples were collected for serum vitamin D and adipokines (adiponectin, leptin, and resistin) analysis using enzyme-linked immunosorbent assay. Statistical analyses were done using SPSS version 26.0 and GraphPad Prism version 8.0.

Results

We observed higher prevalence of obesity among treatment active psychiatric patients (40.7%) compared to treatment naïve group (16.8%). Vitamin D insufficiency and deficiency prevalence were significantly higher among the treatment active group (25.3%; 39.5%; p < 0.001) and associated with increased odds of obesity (91.8%; cOR = 91.84, 95% confidence interval [CI]: 24.94-338.13). Moreover, adiponectin (84.2%: cOR = 14.15, 95% CI: 5.52-36.27), leptin (55.6% cOR = 2.20, 95% CI: 1.04-4.67), and resistin (79.4%: cOR = -8.34, 95% CI: 3.39-20.55) were significantly associated with increased odds of obesity among treatment active psychiatric. Furthermore, treatment active psychiatric patients exhibited inverse correlation for adiponectin and leptin with BMI (r = -0.62; -0.24), and WHtR (r = -0.53; -0.24); however, a moderate positive correlation for resistin with BMI (r = 0.80), HC (r = 0.67), and WHtR (r = 0.65).

Conclusion

Obesity is more prevalent in psychiatric patients on antipsychotics such as Olanzapine and Clozapine. Obesity among treatment active psychiatric patients is associated with vitamin D insufficiency and deficiency, low adiponectin and leptin levels but higher resistin level.

Understanding the Effects of Antipsychotics on Appetite Control

Antipsychotic drugs (APDs) represent a cornerstone in the treatment of schizophrenia and other psychoses. The effectiveness of the first generation (typical) APDs are hampered by so-called extrapyramidal side effects, and they have gradually been replaced by second (atypical) and third-generation APDs, with less extrapyramidal side effects and, in some cases, improved efficacy. However, the use of many of the current APDs has been limited due to their propensity to stimulate appetite, weight gain, and increased risk for developing type 2 diabetes and cardiovascular disease in this patient group. The mechanisms behind the appetite-stimulating effects of the various APDs are not fully elucidated, partly because their diverse receptor binding profiles may affect different downstream pathways. It is critical to identify the molecular mechanisms underlying drug-induced hyperphagia, both because this may lead to the development of new APDs, with lower appetite-stimulating effects but also because such insight may provide new knowledge about appetite regulation in general. Hence, in this review, we discuss the receptor binding profile of various APDs in relation to the potential mechanisms by which they affect appetite.

Association of higher plasma leptin levels with HOMA-IR index, high sensitivity C-reactive protein and glycolipid metabolism in patients with chronic schizophrenia: A multi-center cross-sectional study

BACKGROUND

Previous research has revealed that plasma leptin levels were closely related to glycolipid metabolism in schizophrenic patients. Insulin resistance (IR) and high sensitivity C-reactive protein (hs-CRP) were involved in glucolipid metabolism disorders. This study explored the correlation between plasma higher leptin levels, homeostasis model assessment of insulin resistance (HOMA-IR) index, hs-CRP and glycolipid metabolism in patients with chronic schizophrenia (CS).

METHODS

322 subjects were enrolled, and the psychopathological symptoms of each patient were assessed by a 30-item Positive and Negative Syndrome Scale (PANSS_-30). Patients' plasma leptin levels were measured by enzyme-linked immunosorbent assay (ELISA). Fasting blood glucose (FBG) levels were determined by oxidase method. Insulin levels were tested by electrochemiluminescence, and hs-CRP levels were tested by immunoturbidimetry. IBM SPSS 22.0 was used for data analysis.

RESULTS

Compared to the lower leptin group, patients in the higher leptin group had significantly higher body mass index (BMI), total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL-C), insulin, HOMA-IR and hs-CRP levels; and lower negative factor scores, cognitive factor scores, and PANSS total scores (P < 0.05). Plasma leptin levels in CS patients were positively correlated with BMI, TC, TG, LDL-C, insulin, HOMA-IR and hs-CRP levels, and were negatively correlated with gender (male = 1, Female = 2), positive factor scores, negative factor scores, cognitive factor scores and PANSS total scores. Multiple linear regression analysis revealed that gender, BMI, positive factor scores, PANSS total scores, FBG, LDL-C, insulin, HOMA-IR and hs-CRP levels were independent influencing factors of leptin levels in CS patients (P < 0.05).

CONCLUSION

Gender, BMI, positive factor scores, PANSS total scores, FBG, LDL-C, insulin, HOMA-IR and hs-CRP levels were independent influencing factors of plasma leptin levels in CS patients. Plasma leptin, HOMA-IR and hs-CRP levels should be measured regularly in CS patients to prevent or treat the disorders of glucose and lipid metabolism comorbidity with schizophrenia patients in clinical diagnosis and treatment.

Adiposity in schizophrenia: A systematic review and meta-analysis

OBJECTIVE

Although a relationship between schizophrenia (SCZ), antipsychotic (AP) medication, and metabolic dysregulation is now well established, the effect of adiposity is less well understood. By synthesizing findings from imaging techniques that measure adiposity, our systematic review and meta-analysis (PROSPERO CRD42020192977) aims to determine the adiposity-related effects of illness and treatment in this patient population.

METHODS

We searched MEDLINE, EMBASE, PsychINFO and Scopus for all relevant case-control and prospective longitudinal studies from inception until February 2021. Measures of adiposity including percent body fat (%BF), subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) were analyzed as primary outcomes.

RESULTS

Our search identified 29 articles that used imaging methods to quantify adiposity among patients with SCZ spectrum disorders. Analyses revealed that patients have greater %BF (mean difference (MD) = 3.09%; 95% CI: 0.75-5.44), SAT (MD = 24.29 cm² ; 95% CI: 2.97-45.61) and VAT (MD = 33.73 cm² , 95% CI: 4.19-63.27) compared to healthy controls. AP treatment was found to increase SAT (MD = 31.98 cm² ; 95% CI: 11.33-52.64) and VAT (MD = 16.30 cm² ; 95% CI: 8.17-24.44) with no effect on %BF. However, change in %BF was higher for AP-free/AP-naïve patients compared to treated patients.

CONCLUSION

Our findings indicate that patients with SCZ spectrum disorders have greater adiposity than healthy controls, which is increased by AP treatment. Young, AP-naïve patients may be particularly susceptible to this effect. Future studies should explore the effect of specific APs on adiposity and its relation to overall metabolic health.

Diabetes mellitus in patients using psychotropic medications: How does it work?

Diabetes mellitus (DM) is not a single disease, but a group of diseases that are characterized by chronic hyperglycemia and risk of damage to tissues and organs. The mechanisms of its development are different and due mainly to disorders of insulin secretion or its effects. For this reason, 4 types of DM have been distinguished. One of them is a specific type of DM, determined, inter alia, by the use of certain psychotropic medications. Chronic hyperglycemia often occurs in association with some of these drugs, but in many cases it is categorized erroneously as type 2 (T2DM) or 1 (T1DM). The relationship between DM and psychiatric disorders is bi-directional, involving two mutually independent risk factors for the development of the disease. However, not all patients with a mental illness develop carbohydrate metabolism disorders, which is due to a varied diabetogenic potential and mechanisms of action of psychotropic medications. In clinical practice, questions concerning the frequency of this type of DM, risk factors of its development and hyperglycemic mechanism of psychotropic medications arise. Therefore, the aim of this article is to attempt to answer these questions. From a practical point of view, obtaining such information should allow for the development of appropriate diagnostic and therapeutic procedures.

The Gut Microbiome in Schizophrenia and the Potential Benefits of Prebiotic and Probiotic Treatment

The gut microbiome (GMB) plays an important role in developmental processes and has been implicated in the etiology of psychiatric disorders. However, the relationship between GMB and schizophrenia remains unclear. In this article, we review the existing evidence surrounding the gut microbiome in schizophrenia and the potential for antipsychotics to cause adverse metabolic events by altering the gut microbiome. We also evaluate the current evidence for the clinical use of probiotic and prebiotic treatment in schizophrenia. The current data on microbiome alteration in schizophrenia remain conflicting. Longitudinal and larger studies will help elucidate the confounding effect on the microbiome. Current studies help lay the groundwork for further investigations into the role of the GMB in the development, presentation, progression and potential treatment of schizophrenia.

Gut microbiota: An intermediary between metabolic syndrome and cognitive deficits in schizophrenia

Gut microbiome interacts with the central nervous system tract through the gut-brain axis. Such communication involves neuronal, endocrine, and immunological mechanisms, which allows for the microbiota to affect and respond to various behaviors and psychiatric conditions. In addition, the use of atypical antipsychotic drugs (AAPDs) may interact with and even change the abundance of microbiome to potentially cause adverse effects or aggravate the disorders inherent in the disease. The regulate effects of gut microbiome has been described in several psychiatric disorders including anxiety and depression, but only a few reports have discussed the role of microbiota in AAPDs-induced Metabolic syndrome (MetS) and cognitive disorders. The following review systematically summarizes current knowledge about the gut microbiota in behavior and psychiatric illness, with the emphasis of an important role of the microbiome in the metabolism of schizophrenia and the potential for AAPDs to change the gut microbiota to promote adverse events. Prebiotics and probiotics are microbiota-management tools with documented efficacy for metabolic disturbances and cognitive deficits. Novel therapies for targeting microbiota for alleviating AAPDs-induced adverse effects are also under fast development.

Adiponectin Is Related to Cardiovascular Risk in Severe Mental Illness Independent of Antipsychotic Treatment

Background: Schizophrenia (SCZ) and bipolar disorder (BD) are severe mental illnesses (SMI) associated with elevated cardiovascular disease (CVD) risk, including obesity. Leptin and adiponectin are secreted by adipose tissue, with pro- and anti-inflammatory properties, respectively. The second generation antipsychotics (AP) olanzapine, clozapine, and quetiapine have been associated with high leptin levels in SMI. However, the link between inflammatory dysregulation of leptin and adiponectin and CVD risk in SMI, and how this risk is influenced by body mass and AP medication, is still not completely understood. We investigated herein if leptin, adiponectin or their ratio (L/A ratio) could predict increased CVD risk in SCZ, BD, and in subgroups according to use of antipsychotic (AP) treatment, independent of other cardio-metabolic risk factors. Methods: We measured fasting plasma levels of leptin and adiponectin, and calculated the L/A ratio in n = 1,092 patients with SCZ and BD, in subgroups according to AP treatment, and in n = 176 healthy controls (HC). Differences in the levels of adipokines and L/A between groups were examined in multivariate analysis of covariance, and the correlations between adipokines and body mass index (BMI) with linear regression. CVD risk was defined by total cholesterol/high-density lipoprotein (TC/HDL) and triglyceride/HDL (TG/HDL) ratios. The adipokines and L/A ratios ability to discriminate individuals with TG/HDL and TC/HDL ratios above threshold levels was explored by ROC analysis, and we investigated the possible influence of other cardio-metabolic risk factors on the association in logistic regression analyses. Results: We observed higher leptin levels and L/A ratios in SMI compared with HC but found no differences in adiponectin. Both adipokines were highly correlated with BMI. The low adiponectin levels showed a fair discrimination in ROC analysis of individuals with CVD risk, with AUC between 0.7 and 0.8 for both TC/HDL and TG/HDL, in all groups examined regardless of diagnosis or AP treatment. Adiponectin remained significantly associated with an elevated TC/HDL and TG/HDL ratio in SMI, also after further adjustment with other cardio-metabolic risk factors. Conclusions: Adiponectin is not dysregulated in SMI but is associated with CVD risk regardless of AP treatment regime.

Impact of Psychotropic Medication Effects on Obesity and the Metabolic Syndrome in People With Serious Mental Illness

People with serious mental illness (SMI), including schizophrenia, bipolar disorder, and major depressive disorder, have a higher mortality rate and shortened life expectancy. This is mainly attributable to physical diseases, particularly cardiovascular diseases (CVDs). Important risk factors for CVDs are obesity and other metabolic abnormalities, which are especially prevalent in people with SMI. Several factors contribute to this increased risk, including unhealthy lifestyles. Psychotropic medication independently further increases this risk. In this review we want to examine the relationship between obesity and other components of the metabolic syndrome and psychotropic medication in people with SMI.

Olanzapine in the treatment of anorexia nervosa: a systematic review

Anorexia nervosa, with the highest mortality rate among psychiatric diseases, is characterized by low body mass index, fear of weight gain, and disturbed body image. Even though multiple drugs have been proposed for the treatment of anorexia nervosa, current treatment modalities include nutritional support and psychotherapy. In this study, our aim is to analyze the efficiency and possible adverse effects of olanzapine, an atypical anti-psychotic drug, in the treatment of anorexia nervosa. The studies investigating the efficiency and possible adverse effects of olanzapine in anorexia nervosa have been searched by using 3 databases (Embase, PubMed, and Cochrane Library). DerSimonian-Laird random effects meta-analyses have been used in the statistical analysis. Effect of olanzapine treatment in accordance with the duration and dosage of drug have been analyzed by the determination of 95% confidence intervals (p value < 0.05 is considered as statistically significant). Despite the presence of some contradictory studies, olanzapine treatment has been found beneficial in anorexia nervosa. In addition, analysis reveals that statistically significant beneficial effect of olanzapine treatment is used at high doses and for short duration. Possible side effects include neuroleptic malignant syndrome, hypoglycemia, and heart block in patients suffering from anorexia nervosa. Even though there is obvious need for more comprehensive further studies, current literature favors olanzapine treatment. The efficiency of olanzapine is considered to be related to changes in dopaminergic and serotonergic system in anorexic patients both in terms of neurotransmitter levels and receptor activity.

Psychiatric drugs impact mitochondrial function in brain and other tissues

Mitochondria have been linked to the etiology of schizophrenia (SZ). However, studies of mitochondria in SZ might be confounded by the effects of pharmacological treatment with antipsychotic drugs (APDs) and other common medications. This review summarizes findings on relevant mitochondria mechanisms underlying SZ, and the potential impact of psychoactive drugs including primarily APDs, but also antidepressants and anxiolytics. The summarized data suggest that APDs impair mitochondria function by decreasing Complex I activity and ATP production and dissipation of the mitochondria membrane potential. At the same time, in the brains of patients with SZ, antipsychotic drug treatment normalizes gene expression modules enriched in mitochondrial genes that are decreased in SZ. This indicates that APDs may have both positive and negative effects on mitochondria. The available evidence suggests three conclusions i) alterations in mitochondria functions in SZ exist prior to APD treatment, ii) mitochondria alterations in SZ can be reversed by APD treatment, and iii) APDs directly cause impairment of mitochondria function. Overall, the mechanisms of action of psychiatric drugs on mitochondria are both direct and indirect; we conclude the effects of APDs on mitochondria may contribute to both their therapeutic and metabolic side effects. These studies support the hypothesis that neuronal mitochondria are an etiological factor in SZ. Moreover, APDs and other drugs must be considered in the evaluation of this pathophysiological role of mitochondria in SZ. Considering these effects, pharmacological actions on mitochondria may be a worthwhile target for further APD development.

Leptin and psychiatric illnesses: does leptin play a role in antipsychotic-induced weight gain?

Antipsychotic-induced weight gain is the most prevalent somatic adverse event occurring in patients treated by antipsychotics, especially atypical antipsychotics. It is of particular interest because of its repercussion on cardiovascular morbidity and mortality especially now that the use of second-generation antipsychotics has been extended to other mental health illnesses such as bipolar disorders and major depressive disorder. The mechanism underlying antipsychotics-induced weight gain is still poorly understood despite a significant amount of work on the topic. Recently, there has been an on-going debate of tremendous research interest on the relationship between antipsychotic-induced weight gain and body weight regulatory hormones such as leptin. Given that, researchers have brought to light the question of leptin's role in antipsychotic-induced weight gain. Here we summarize and discuss the existing evidence on the link between leptin and weight gain related to antipsychotic drugs, especially atypical antipsychotics.

Cannabis consumption and non-alcoholic fatty liver disease. A three years longitudinal study in first episode non-affective psychosis patients

INTRODUCTION

Increased incidence of obesity and excess weight lead to an increased incidence of non-alcoholic fatty liver disease (NAFLD). Recent evidence indicates a protective effect of cannabis consumption on weight gain and related metabolic alterations in psychosis patients. Overall, patients are at greater risk of presenting fatty diseases, such as NAFLD, partly due to lipid and glycemic metabolic disturbances. However, there are no previous studies on the likely effect of cannabis on liver steatosis. We aimed to explore if cannabis consumption had an effect on hepatic steatosis, in a sample of first-episode (FEP) non-affective psychosis.

MATERIAL AND METHODS

A total of 390 patients were evaluated at baseline and after 3 years of initiating the antipsychotic treatment. Anthropometric measurements and liver, lipid, and glycemic parameters were obtained at both time points. All but 6.7% of patients were drug-naïve at entry, and they self-reported their cannabis use at both time points. Liver steatosis and fibrosis were evaluated through validated clinical scores (Fatty Liver Index [FLI], Fibrosis-4 [FIB-4], and NAFLD).

RESULTS

At 3-year follow-up, cannabis users presented significantly lower FLI scores than non-users (F = 13.874; p < .001). Moreover, cannabis users less frequently met the criteria for liver steatosis than non-users (X² = 7.97, p = .019). Longitudinally, patients maintaining cannabis consumption after 3 years presented the smallest increment in FLI over time, which was significantly smaller than the increment in FLI presented by discontinuers (p = .022) and never-users (p = .016). No differences were seen in fibrosis scores associated with cannabis.

CONCLUSIONS

Cannabis consumption may produce a protective effect against liver steatosis in psychosis, probably through the modulation of antipsychotic-induced weight gain.

Adiponectin is decreased in bipolar depression

Objectives: Bipolar disorder (BD) is often accompanied by medical comorbidities, which affect illness course and prognosis. Adipokines may not only be involved in the aetiopathogenetic mechanisms of these comorbidities; there might be an association between adipokines and the neuropsychiatric core features of BD such as mood disturbances and cognitive deficits.Methods: In this investigation, fasting blood samples from 120 individuals with BD (75 euthymic and 45 with mild depressive symptoms) and 68 control subjects were taken and adiponectin and leptin concentrations were analysed.Results: We found that, in female participants, adiponectin levels differed significantly between patients and controls indicating lower levels in individuals with BD, even after controlling for BMI (F(1,92) = 4.65, P = 0.034, partial η² = 0.05). After stratification by mood status we found a significant difference in adiponectin between controls, euthymic and depressive patients (F(2, 180) = 4.90, P = 0.008, partial η² = 0.05).Conclusions: This investigation confirms previous findings of an association between low adiponectin levels and depressive state in individuals with BD. Beyond its immediate effect on central nervous system function, adiponectin might interfere with pathophysiological mechanisms of BD and its somatic comorbidities via involvement in metabolic and inflammatory processes.

The effects of antipsychotic medications on microbiome and weight gain in children and adolescents

BACKGROUND

Atypical antipsychotics, also known as second-generation antipsychotics, are commonly prescribed as treatment for psychotic disorders in adults, as well as in children and adolescents with behavioral problems. However, in many cases, second-generation antipsychotics have unwanted side effects, such as weight gain, potentially further increasing risk for morbidities including obesity, diabetes, and cardiovascular disease. While various mechanisms for this weight gain have been proposed, including effects on metabolic hormone signaling, recent evidence points to the importance of the gut microbiome in this process. The microbial communities residing within the gut are affected by second-generation antipsychotics and can confer weight gain.

MAIN TEXT

This review summarizes recent findings and presents data linking second-generation antipsychotics, gut microbiota alterations and weight gain. The review focuses on children and adolescent populations, which have not previously received much attention, but are of great interest because they may be most vulnerable to gut microbiome changes and may carry long-term metabolic effects into adulthood.

CONCLUSIONS

We present correlations between second-generation antipsychotics, gut microbiota alterations and weight gain, and suggest some mechanisms that may link them. A better understanding of the underlying mechanisms may lead to the design of improved treatments for psychotic disorders with fewer harmful side effects.

Meta-Analysis of Neuropsychological Studies in Panic Disorder Patients: Evidence of Impaired Performance during the Emotional Stroop Task

BACKGROUND

Recent investigations have highlighted significant differences in verbal recall between patients with panic disorder (PD) and controls. These studies have highlighted that verbal memory and working memory could be impaired in PD.

OBJECTIVES

The objective of the present meta-analysis is to confirm this hypothesis, reviewing the studies that have investigated neurocognitive testing in PD.

METHODS

We performed a systematic literature search for studies published between 1980 and 2015 that reported cognitive measurements in PD patients and controls. Effect size estimates were computed using the restricted maximum likelihood model. Only case-control studies were selected for this meta-analysis. We included studies that made a direct comparison between PD subjects and healthy controls. The diagnostic group consisted of adult patients aged over 18 years diagnosed with PD. We excluded the studies that did not employ a case-control design. All statistical analyses were carried out on R using the "metafor" package version 1.9-8. The effect size for each study neuropsychological test was calculated using the mean and SD of performance results, and p values < 0.05 were considered significant.

RESULTS

We identified few studies that tested verbal memory and executive functions in PD patients and controls, and this difference was not significant. On the other hand, there are several studies that have used the emotional Stroop task to assess cognitive functions in PD. There is no robust evidence of impairment of memory function in PD; however, when considering the emotional Stroop task, it was found that PD patients performed slower (p < 0.01) than healthy controls for all three types of stimuli (neutral, negative, positive).

CONCLUSION

This meta-analysis included a small number of studies, which may have introduced bias into the analysis. However, there is some evidence of impairment of neurocognitive functions in PD when performing the emotional Stroop task. Furthermore, the paucity of studies evaluating neurocognition in PD suggests the need for further research in this field in order to draw meaningful conclusions.

Appetite regulating hormones in first-episode psychosis: A systematic review and meta-analysis

We aimed to perform a systematic review and meta-analysis of appetite regulating hormones in patients with first-episode psychosis (FEP). Meta-analyses were conducted using random-effects models with Hedges' g as the effect size estimate. We identified 31 eligible studies, investigating the levels of 7 appetite regulating hormones (adiponectin, insulin, leptin, ghrelin, orexin, resistin and visfatin) in 1792 FEP patients and 1364 controls. The insulin levels in FEP patients were higher than in controls (g = 0.34, 95%CI: 0.19 - 0.49, p < 0.001), even considering only antipsychotic-naïve patients (g = 0.39, 95%CI: 0.12 - 0.66, p = 0.005). The severity of negative symptoms was positively associated with the effect size estimates (β = 0.08, 95%CI: 0.01 - 0.16, p = 0.030). Moreover, we found lower levels of leptin in antipsychotic-naïve FEP patients (g = -0.62, 95%CI: -1.11 - 0.12, p = 0.015). Impaired appetite regulation, in terms of elevated insulin levels and decreased leptin levels, occurs in early psychosis, before antipsychotic treatment. Hyperinsulinemia might be related to negative symptoms.

Can prebiotics assist in the management of cognition and weight gain in schizophrenia?

Schizophrenia is among the top half of the 25 leading causes of disabilities worldwide with a 10-20 year decrease in life expectancy. Ineffective pharmacotherapy in the management of cognitive deficits and weight gain are known to be significant contributors; therefore interventions that may mitigate one, or both, of these parameters would be highly beneficial. Manipulation of the gut microbiome using dietary supplements such as prebiotics may be one such intervention. Preclinical studies have shown that a 2-4 week dietary supplementation with a prebiotic has beneficial effects on learning and memory, and prevents pro-inflammatory signals that are detrimental to cognitive processes. Furthermore, prebiotics influence metabolism, and in obesity they increase the expression of anorexigenic gut hormones such as peptide tyrosine tyrosine, glucagon-like peptide 1 and leptin, as well as decrease levels of orexigenic hormones such as ghrelin. Despite compelling evidence for the pro-cognitive and neuroprotective effects of prebiotics in rodents, their ability to alleviate cognitive deficits or enhance cognition needs to be evaluated in humans. Here we suggest that important symptoms associated with schizophrenia, such as cognitive impairment and weight gain, may benefit from concurrent prebiotic therapy.