Association between Serum Lipids and Antipsychotic Response in Schizophrenia

Medication Induced Dyslipidemia in Children

PURPOSE OF REVIEW

The prevalence of dyslipidemia in the pediatric population continues to rise, increasing the future risk of atherosclerotic cardiovascular disease (ASCVD) as these children transition to adulthood. Timely diagnosis and intervention, beginning at a young age, is important in reducing the risk of ASCVD and preventing premature mortality in this vulnerable population. Implementation of a heart-healthy lifestyle should be encouraged in all children, and, when appropriate, the role of medication discussed in those at-risk. The purpose of this review is to discuss the impact of non-lipid lowering medications which affect lipid and lipoprotein metabolism in children (< 18 years-of-age).

RECENT FINDINGS

According to National Center of Health Statistics, there has been a steady rise of pediatric obesity and cardiovascular disease (CVD) risk amongst youth over the last 2 decades, with roughly 1 out of 5 children having a BMI > 95th percentile for their age and gender. Such a rise can contribute to an increase of CVD risk factors, which play a role in the development of atherosclerosis. Evidence of atherosclerosis appears as early as childhood, progresses throughout adolescences, and accelerates after 20 years-of-age. Although some children are genetically predisposed to dyslipidemia, many have elevated lipids and lipoproteins as a result of unhealthy lifestyles - high fat, high carbohydrate diets, lack of exercise, and use of medications for other health conditions. In a 2023 survey, it was predicted that approximately 40.1% of children < 17 years-of-age have had at least one medication prescribed for a short or long-term health condition within the past 12 months. Clinicians should be aware of health conditions and medications that can adversely affect lipid levels when evaluating and treating children with lipid disorders. With the increased prevalence of lipid disorders in the pediatric population, healthcare providers are searching for both primary and secondary causes including the influence of certain medications or drug classes known to cause lipid abnormalities in adults, identifying similar findings amongst children. These include but are not limited to corticosteroids, retinoid agents, beta blockers, oral contraceptives, chemotherapy agents, antiretroviral medications, androgenic steroids and behavioral medications.

The impact of weight gain on antipsychotic nonadherence or discontinuation: A systematic review and meta-analysis

BACKGROUND

Nonadherence/discontinuation of antipsychotic (AP) medications represents an important clinical issue in patients across psychiatric disorders, including schizophrenia spectrum disorders (SSDs). While antipsychotic-induced weight gain (AIWG) is a reported contributor to nonadherence, a systematic review of the association between AIWG and medication nonadherence/discontinuation has not been explored previously.

METHOD

A systematic search was conducted in MEDLINE, EMBASE, PsychINFO, CINAHL, and CENTRAL databases, among others, to help identify all studies which explored adherence, study dropouts, AP switching and/or discontinuations attributable to AIWG among individuals with severe mental illness. A meta-analysis was also completed where applicable.

RESULTS

We identified two categories of studies for the meta-analysis. Category 1 included three studies, which compared measures of AP adherence or discontinuation across BMI classes/degrees of self-reported weight gain. When compared to normal weight individuals receiving APs or those who did not report AIWG, individuals who were either overweight or obese or reported weight gain in relation to AP use had an increased odds of AP nonadherence (OR 2.37; 95% CI 1.51-3.73; p = 0.0002). Category 2 had 14 studies which compared measures of discontinuation related to weight gain reported as an adverse effect across different APs. Olanzapine was associated with a 3.32 times (95% CI 2.32-4.74; p < 0.00001) increased likelihood of nonadherence or discontinuation when compared to other APs with lower weight gain liabilities. Similarly, APs with moderate weight gain liability (paliperidone, risperidone, and quetiapine) increased the odds of nonadherence or discontinuation by 2.25 (95% CI 1.31-3.87; p = 0.003) when compared to APs considered to have lower weight gain liability (i.e. haloperidol and aripiprazole). The qualitative summary also confirmed these findings.

CONCLUSION

This review and meta-analysis suggests that AIWG influences medication nonadherence/discontinuation, whereby APs with higher weight gain liability are associated with nonadherence/discontinuation. Additional studies are needed to confirm these findings.

Identification of serum metabolic traits of AIWG in first-episode schizophrenia patients

BACKGROUND

Antipsychotic-induced weight gain (AIWG) is a common side effect of antipsychotic drugs and may lead to cardiometabolic comorbidities. There is an urgent public health need to identify patients at high risk of AIWG and determine potential biomarkers for AIWG.

METHODS

In the Sequential Multiple-Assignment Randomized Trials to Compare Antipsychotic Treatments (SMART-CAT) trail, first-episode schizophrenia patients were randomly assigned to olanzapine, risperidone, perphenazine, amisulpride or aripiprazole for 8 weeks. We applied absolute quantitative lipidomics at baseline and after 8 weeks of antipsychotic treatment in 80 patients. To evaluate the effects of AIWG on lipid profile, 25 patients with ≥ 7% weight changes (weight gain, WG) and 28 patients with <|3|% weight changes (weight stable, WS) were investigated, separately.

RESULTS

We found that baseline CerP(d40:3) and PC(20:1_22:6) were positively associated with weight changes at follow-up (r > 0.4, pFDR < 0.05). Additionally, baseline CerP(d40:3) and PC(20:1_22:6) independently predicted rapid weight gain, with receiver operating curve (ROC) of 0.76 (95% CI: 0.63-0.90), and 0.75 (95% CI: 0.62-0.88), respectively. Compared with baseline, levels of 45 differential lipid metabolites (fold change > 1.2, VIP > 1 and pFDR < 0.05) were significantly higher in the WG group. Interestingly, no differential lipid metabolites were identified in the WS group. The LASSO regression model identified 18 AIWG lipid signatures, including 2 cholesterol esters (ChEs), 1 diglyceride (DG), 12 phosphatidylcholines (PCs), 1 phosphatidylglycerol (PG), 1 phosphatidylinositol (PI), and 1 sphingomyelin (SM), with the ChE(16:1) contributing the most. Furthermore, the level changes of ChE(16:1) were positively associated with weight gain(r = 0.67, pFDR < 0.05).

CONCLUSION

Our findings indicate that lipid profile may serve as predictors of rapid weight gain in schizophrenia and provide useful markers for AIWG intervention.

Altered lipidomics biosignatures in schizophrenia: A systematic review

Multiomics approaches have significantly aided the identification of molecular signatures in complex neuropsychiatric disorders. Lipidomics, one of the newest additions in the -omics family, sheds light on lipid profiles and is an emerging methodological tool to study schizophrenia pathobiology, as lipid dysregulation has been repeatedly observed in schizophrenia. In this review, we performed a detailed literature search for lipidomics studies in schizophrenia. Following elaborate inclusion/exclusion criteria, we focused on human studies in schizophrenia and schizophrenia-related diagnoses in brain and blood specimens, including serum plasma, platelets and red blood cells. Eighteen studies fulfilled our inclusion criteria, of which five were conducted in the brain, 12 in peripheral material and one in both. Here, we first provide background on lipidomics and the main lipid categories addressed, review in detail the included literature and look for common lipidomics patterns in brain and the periphery that emerge from these studies. Furthermore, we highlight current limitations in schizophrenia lipidomics research and underline the need for following up on lipidomics results with complementary molecular approaches.

Alterations to sphingolipid metabolism from antipsychotic administration in healthy volunteers are restored following the use of cannabidiol

Randomized clinical trials substantiate cannabidiol (CBD) as a next-generation antipsychotic, effective in alleviating positive and negative symptoms associated with psychosis, while minimising the adverse effects seen with established treatments. Although the mechanisms remain debated, CBD is known to induce drug-responsive changes in lipid-based retrograde neurotransmitters. Lipid aberrations are also frequently observed with antipsychotics, which may contribute to their efficacy or increase the risk of undesirables, including metabolic dysfunction, obesity and dyslipidaemia. Our study investigated CBD's impact following lipid responses triggered by interaction with second-generation antipsychotics (SGA) in a randomized phase I safety study. Untargeted mass spectrometry assessed the lipidomic profiles of human sera, collected from 38 healthy volunteers. Serum samples were obtained prior to commencement of any medication (t = 0), 3 days after consecutive administration of one of the five, placebo-controlled, treatment arms designed to achieve steady-state concentrations of each SGA (amisulpride, 150 mg/day; quetiapine, 300 mg/day; olanzapine 10 mg/day; risperidone, 3 mg/day), and after six successive days of SGA treatment combined with CBD (800 mg/day). Receiver operating characteristics (ROC) refined 3712 features to a putative list of 15 lipids significantly altered (AUC > 0.7), classified into sphingolipids (53 %), glycerolipids (27 %) and glycerophospholipids (20 %). Targeted mass spectrometry confirmed reduced sphingomyelin and ceramide levels with antipsychotics, which mapped along their catabolic pathway and were restored by CBD. These sphingolipids inversely correlated with body weight after olanzapine, quetiapine, and risperidone treatment, where CBD appears to have arrested or attenuated these effects. Herein, we propose CBD may alleviate aberrant sphingolipid metabolism and that further investigation into sphingolipids as markers for monitoring side effects of SGAs and efficacy of CBD is warranted.

Lipid-modifying agents and risk of all-cause, natural and suicide mortality in schizophrenia: nationwide cohort study

BACKGROUND

Individuals with schizophrenia face high mortality risks. The effects of lipid-modifying agents on this risk remain understudied.

AIM

This study was conducted to investigate the effects of lipid-modifying agents on mortality risk in people with schizophrenia.

METHOD

This nationwide cohort study collected the data of people with schizophrenia from Taiwan's National Health Insurance Research Database for the period between 1 January 2001 and 31 December 2019. Multivariable Cox proportional hazards regression with a time-dependent model was used to estimate the hazard ratio for mortality associated with each lipid-modifying agent.

RESULTS

This study included 110 300 people with schizophrenia. Of them, 22 528 died (19 754 from natural causes and 1606 from suicide) during the study period, as confirmed using data from Taiwan's national mortality database. The use of lipid-modifying agents was associated with reduced risks of all-cause (adjusted hazard ratio [aHR]:0.37; P < 0.001) and natural (aHR:0.37; P < 0.001) mortality during a 5-year period. Among the lipid-modifying agents, statins and fibrates were associated with reduced risks of all-cause mortality (aHRs:0.37 and 0.39, respectively; P < 0.001 for both) and natural mortality (aHRs: 0.37 and 0.42, respectively; P < 0.001 for both). Notably, although our univariate analysis indicated an association between the use of lipid-modifying agents and a reduced risk of suicide mortality, the multivariate analysis revealed no significant association.

CONCLUSIONS

Lipid-modifying agents, particularly statins and fibrates, reduce the risk of mortality in people with schizophrenia. Appropriate use of lipid-modifying agents may bridge the mortality gap between these individuals and the general population.

High-Density Lipoprotein Correlates with Cognitive Functioning in Schizophrenic Women

(1) Background: Schizophrenia is a chronic and progressive neuropsychiatric illness. Apart from positive and negative symptoms, 98% of the population diagnosed with schizophrenia have impaired cognitive functioning, which significantly influences the quality of life. The correlation between lipids and cognitive functioning has been well established. Our study aimed to investigate correlations between cognitive functions, the severity of schizophrenia symptoms, and lipid profiles. (2) Methods: Fifty-two women diagnosed with schizophrenia participated in this study. Cognitive functioning was measured using the Wisconsin Card Sorting Test (WCST). The Positive and Negative Symptom Scale (PANSS) was used. The serum lipid profile, including low-density lipoproteins (LDLs), high-density lipoproteins (HDLs), and triglycerides was measured. (3) Results: Better cognitive functions were associated with normal HDL levels, while low HDL levels correlated with worse WSCT scores. Only the PANSS negative subscale showed a correlation with HDL levels. Correlations with chronicity of schizophrenia and the patient's age with poorer cognitive functions, but not with symptom severity, were detected. Early/late age at onset did not influence WSCT scores. (4) Conclusions: Our results suggest high HDL levels might be a protective factor against cognitive impairment. The influences of age and illness duration also play a vital role in cognitive performance.

Assessing regional intracortical myelination in schizophrenia spectrum and bipolar disorders using the optimized T1w/T2w-ratio

BACKGROUND

Dysmyelination could be part of the pathophysiology of schizophrenia spectrum (SCZ) and bipolar disorders (BPD), yet few studies have examined myelination of the cerebral cortex. The ratio of T1- and T2-weighted magnetic resonance images (MRI) correlates with intracortical myelin. We investigated the T1w/T2w-ratio and its age trajectories in patients and healthy controls (CTR) and explored associations with antipsychotic medication use and psychotic symptoms.

METHODS

Patients with SCZ (n = 64; mean age = 30.4 years, s.d. = 9.8), BPD (n = 91; mean age 31.0 years, s.d. = 10.2), and CTR (n = 155; mean age = 31.9 years, s.d. = 9.1) who participated in the TOP study (NORMENT, University of Oslo, Norway) were clinically assessed and scanned using a General Electric 3 T MRI system. T1w/T2w-ratio images were computed using an optimized pipeline with intensity normalization and field inhomogeneity correction. Vertex-wise regression models were used to compare groups and examine group × age interactions. In regions showing significant differences, we explored associations with antipsychotic medication use and psychotic symptoms.

RESULTS

No main effect of diagnosis was found. However, age slopes of the T1w/T2w-ratio differed significantly between SCZ and CTR, predominantly in frontal and temporal lobe regions: Lower T1w/T2w-ratio values with higher age were found in CTR, but not in SCZ. Follow-up analyses revealed a more positive age slope in patients who were using antipsychotics and patients using higher chlorpromazine-equivalent doses.

CONCLUSIONS

While we found no evidence of reduced intracortical myelin in SCZ or BPD relative to CTR, different regional age trajectories in SCZ may suggest a promyelinating effect of antipsychotic medication.

New role of platelets in schizophrenia: predicting drug response

Background

Elevated platelet count (PLTc) is associated with first-episode schizophrenia and adverse outcomes in individuals with precursory psychosis. However, the impact of antipsychotic medications on PLTc and its association with symptom improvement remain unclear.

Aims

We aimed to investigate changes in PLTc levels following antipsychotic treatment and assess whether PLTc can predict antipsychotic responses and metabolic changes after accounting for other related variables.

Methods

A total of 2985 patients with schizophrenia were randomised into seven groups. Each group received one of seven antipsychotic treatments and was assessed at 2, 4 and 6 weeks. Clinical symptoms were evaluated using the positive and negative syndrome scale (PANSS). Additionally, we measured blood cell counts and metabolic parameters, such as blood lipids. Repeated measures analysis of variance was used to examine the effect of antipsychotics on PLTc changes, while structural equation modelling was used to assess the predictive value of PLTc on PANSS changes.

Results

PLTc significantly increased in patients treated with aripiprazole (F=6.00, p=0.003), ziprasidone (F=7.10, p<0.001) and haloperidol (F=3.59, p=0.029). It exhibited a positive association with white blood cell count and metabolic indicators. Higher baseline PLTc was observed in non-responders, particularly in those defined by the PANSS-negative subscale. In the structural equation model, PLTc, white blood cell count and a latent metabolic variable predicted the rate of change in the PANSS-negative subscale scores. Moreover, higher baseline PLTc was observed in individuals with less metabolic change, although this association was no longer significant after accounting for baseline metabolic values.

Conclusions

Platelet parameters, specifically PLTc, are influenced by antipsychotic treatment and could potentially elevate the risk of venous thromboembolism in patients with schizophrenia. Elevated PLTc levels and associated factors may impede symptom improvement by promoting inflammation. Given PLTc's easy measurement and clinical relevance, it warrants increased attention from psychiatrists.

Trial registration number

ChiCTR-TRC-10000934.

The Role of Total White Blood Cell Count in Antipsychotic Treatment for Patients with Schizophrenia

BACKGROUND

Total white blood cell count (TWBCc), an index of chronic and low-grade inflammation, is associated with clinical symptoms and metabolic alterations in patients with schizophrenia. The effect of antipsychotics on TWBCc, predictive values of TWBCc for drug response, and role of metabolic alterations require further study.

METHODS

Patients with schizophrenia were randomized to monotherapy with risperidone, olanzapine, quetiapine, aripiprazole, ziprasidone, perphenazine or haloperidol in a 6-week pharmacological trial. We repeatedly measured clinical symptoms, TWBCc, and metabolic measures (body mass index, blood pressure, waist circumference, fasting blood lipids and glucose). We used mixed-effect linear regression models to test whether TWBCc can predict drug response. Mediation analysis to investigate metabolic alteration effects on drug response.

RESULTS

At baseline, TWBCc was higher among patients previously medicated. After treatment with risperidone, olanzapine, quetiapine, perphenazine, and haloperidol, TWBCc decreased significantly (p < 0.05). Lower baseline TWBCc predicted greater reductions in Positive and Negative Syndrome Scale (PANSS) total and negative scores over time (p < 0.05). We found significant mediation of TWBCc for effects of waist circumference, fasting low-density lipoprotein cholesterol, and glucose on reductions in PANSS total scores and PANSS negative subscale scores (p < 0.05).

CONCLUSION

TWBCc is affected by certain antipsychotics among patients with schizophrenia, with decreases observed following short-term, but increases following long-term treatment. TWBCc is predictive of drug response, with lower TWBCc predicting better responses to antipsychotics. It also mediates the effects of certain metabolic measures on improvement of negative symptoms. This indicates that the metabolic state may affect clinical manifestations through inflammation.

Metabolomics, Lipidomics, and Antipsychotics: A Systematic Review

Antipsychotics are an important pharmacotherapy option for the treatment of many mental illnesses. Unfortunately, selecting antipsychotics is often a trial-and-error process due to a lack of understanding as to which medications an individual patient will find most effective and best tolerated. Metabolomics, or the study of small molecules in a biosample, is an increasingly used omics platform that has the potential to identify biomarkers for medication efficacy and toxicity. This systematic review was conducted to identify metabolites and metabolomic pathways associated with antipsychotic use in humans. Ultimately, 42 studies were identified for inclusion in this review, with all but three studies being performed in blood sources such as plasma or serum. A total of 14 metabolite classes and 12 lipid classes were assessed across studies. Although the studies were highly heterogeneous in approach and mixed in their findings, increases in phosphatidylcholines, decreases in carboxylic acids, and decreases in acylcarnitines were most consistently noted as perturbed in patients exposed to antipsychotics. Furthermore, for the targeted metabolomic and lipidomic studies, seven metabolites and three lipid species had findings that were replicated. The most consistent finding for targeted studies was an identification of a decrease in aspartate with antipsychotic treatment. Studies varied in depth of detail provided for their study participants and in study design. For example, in some cases, there was a lack of detail on specific antipsychotics used or concomitant medications, and the depth of detail on sample handling and analysis varied widely. The conclusions here demonstrate that there is a large foundation of metabolomic work with antipsychotics that requires more complete reporting so that an objective synthesis such as a meta-analysis can take place. This will then allow for validation and clinical application of the most robust findings to move the field forward. Future studies should be carefully controlled to take advantage of the sensitivity of metabolomics while limiting potential confounders that may result from participant heterogeneity and varied analysis approaches.

Comparative predictive efficacy of atherogenic indices on metabolic syndrome in patients with schizophrenia

BACKGROUND

Schizophrenia patients endure high risks of metabolic syndrome and related cardiovascular mortality. Evidence on comparing detective power among atherogenic indices of the metabolic syndrome in schizophrenia patients with antipsychotics treatment is still lacking.

METHOD

We recruited 128 schizophrenia patients and collected blood samples to determine plasma levels of fasting glucose, total cholesterol, triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol. Five components of metabolic syndrome were assessed. Atherogenic indices, such as atherogenic index of plasma (AIP), atherogenic coefficient (AC), Castelli's risk index-I (CRI-I) and Castelli's risk index-II (CRI-II), were calculated. The area under the receiver operating characteristics curve (AUC) and regression analysis were adopted to compare the detective power of each atherogenic index for metabolic syndrome. The optimal cutoff points using maximization of Youden's index and the positive likelihood ratios were calculated.

RESULTS

51 (39.8 %) had metabolic syndrome. AIP (0.2 ± 0.2 vs. 0.6 ± 0.2), AC (2.5 ± 0.9 vs. 3.4 ± 0.9), CRI-I (3.5 ± 0.9 vs. 4.4 ± 0.9,) and CRI-II (2.1 ± 0.7 vs. 2.6 ± 0.7) were higher in the group with metabolic syndrome (all p < 0.001). AIP had the highest AUC (0.845, 95 % CI: 0.770, 0.920). The optimal cut-off point of AIP to predict metabolic syndrome was 0.4 with the corresponding sensitivity 83.7 %, specificity 80.3 %, and positive likelihood ratio 4.2. Regression analysis revealed that only AIP significantly correlated with the metabolic syndrome (p < 0.001).

CONCLUSION

Among atherogenic indices, only AIP has superior discrimination for detecting metabolic syndrome in schizophrenia with antipsychotics treatment.

Clinical improvement in schizophrenia during antipsychotic treatment in relation to changes in glucose parameters: A systematic review

Antipsychotics (APs) are the cornerstone of treatment for schizophrenia (SCZ) spectrum disorders. Previous research suggests that there may be a positive association between AP-induced weight gain and/or dyslipidemia and improvement in psychiatric symptoms, often referred to as a "metabolic threshold". To determine whether a similar relationship exists for glucose parameters, we conducted a systematic search in six databases from inception to June 2022 for all longitudinal studies that directly examined the relationship between changes in glucose-related outcomes and changes in psychopathology among patients with SCZ treated with APs. We identified 10 relevant studies and one additional study that considered cognition. In most cases, we found that increased levels of fasting glucose and insulin following treatment were associated with clinical improvement. These findings contribute to existing literature that could suggest a common mechanism between AP action and metabolic side effects and support a need for additional work aimed at exploring the validity of a glucose-psychopathology relation in SCZ.

Brain Lipids and Lipid Droplet Dysregulation in Alzheimer's Disease and Neuropsychiatric Disorders

Background

Lipids are essential components of the structure and for the function of brain cells. The intricate balance of lipids, including phospholipids, glycolipids, cholesterol, cholesterol ester, and triglycerides, is crucial for maintaining normal brain function. The roles of lipids and lipid droplets and their relevance to neurodegenerative and neuropsychiatric disorders (NPDs) remain largely unknown.

Summary

Here, we reviewed the basic role of lipid components as well as a specific lipid organelle, lipid droplets, in brain function, highlighting the potential impact of altered lipid metabolism in the pathogenesis of Alzheimer's disease (AD) and NDPs.

Key Messages

Brain lipid dysregulation plays a pivotal role in the pathogenesis and progression of neurodegenerative and NPDs including AD and schizophrenia. Understanding the cell type-specific mechanisms of lipid dysregulation in these diseases is crucial for identifying better diagnostic biomarkers and for developing therapeutic strategies aiming at restoring lipid homeostasis.

Insulin-like Growth Factor 2 (IGF-2) and Insulin-like Growth Factor Binding Protein 7 (IGFBP-7) Are Upregulated after Atypical Antipsychotics in Spanish Schizophrenia Patients

Insulin-like growth factor 2 (IGF-2) and IGF binding protein 7 (IGFBP-7) have been related to schizophrenia (SZ) due to their implication in neurodevelopment. The purpose of this study was to assess whether the alterations in IGF-2 and IGFBP-7 in SZ patients are intrinsically related to the psychiatric disorder itself or are a secondary phenomenon due to antipsychotic treatment. In order to test this hypothesis, we measured plasma IGF-2 and IGFBP-7 in drug-naïve first episode (FE) and multiple episodes or chronic (ME) SZ Caucasian patients who have been following treatment for years. A total of 55 SZ patients (FE = 15, ME = 40) and 45 healthy controls were recruited. The Positive and Negative Syndrome Scale (PANSS) and the Self-Assessment Anhedonia Scale (SAAS) were employed to check schizophrenic symptomatology and anhedonia, respectively. Plasma IGF-2 and IGFBP-7 levels were measured by Enzyme-Linked Immunosorbent Assay (ELISA). The FE SZ patients had much lower IGF-2, but not IGFBP-7, than controls. Moreover, both IGF-2 and IGFBP-7 significantly increased after atypical antipsychotic treatment (aripiprazole, olanzapine, or risperidone) in these patients. On the other hand, chronic patients showed higher levels of both proteins when compared to controls. Our study suggests that circulatory IGF-2 and IGFBP-7 increase after antipsychotic treatment, regardless of long-term conditions and being lower in drug-naïve FE patients.

Clozapine's multiple cellular mechanisms: What do we know after more than fifty years? A systematic review and critical assessment of translational mechanisms relevant for innovative strategies in treatment-resistant schizophrenia

Almost fifty years after its first introduction into clinical care, clozapine remains the only evidence-based pharmacological option for treatment-resistant schizophrenia (TRS), which affects approximately 30% of patients with schizophrenia. Despite the long-time experience with clozapine, the specific mechanism of action (MOA) responsible for its superior efficacy among antipsychotics is still elusive, both at the receptor and intracellular signaling level. This systematic review is aimed at critically assessing the role and specific relevance of clozapine's multimodal actions, dissecting those mechanisms that under a translational perspective could shed light on molecular targets worth to be considered for further innovative antipsychotic development. In vivo and in vitro preclinical findings, supported by innovative techniques and methods, together with pharmacogenomic and in vivo functional studies, point to multiple and possibly overlapping MOAs. To better explore this crucial issue, the specific affinity for 5-HT₂R, D1R, α_2c, and muscarinic receptors, the relatively low occupancy at dopamine D2R, the interaction with receptor dimers, as well as the potential confounder effects resulting in biased ligand action, and lastly, the role of the moiety responsible for lipophilic and alkaline features of clozapine are highlighted. Finally, the role of transcription and protein changes at the synaptic level, and the possibility that clozapine can directly impact synaptic architecture are addressed. Although clozapine's exact MOAs that contribute to its unique efficacy and some of its severe adverse effects have not been fully understood, relevant information can be gleaned from recent mechanistic understandings that may help design much needed additional therapeutic strategies for TRS.

Alterations of Plasma Lipids in Adult Women With Major Depressive Disorder and Bipolar Depression

Lipidomics has been established as a potential tool for the investigation of mental diseases. However, the composition analysis and the comparison of the peripheral lipids regarding adult women with major depressive depression (MDD) or bipolar depression (BPD) has been poorly addressed. In the present study, age-matched female individuals with MDD (n = 28), BPD (n = 22) and healthy controls (HC, n = 25) were enrolled. Clinical symptoms were assessed and the plasma samples were analyzed by comprehensive lipid profiling based on liquid chromatography-mass spectrometry (LC/MS). We found that the composition of lipids was remarkably changed in the patients with MDD and BPD when compared to HC or compared to each other. Moreover, we identified diagnostic potential biomarkers comprising 20 lipids that can distinguish MDD from HC (area under the curve, AUC = 0.897) and 8 lipids that can distinguish BPD from HC (AUC = 0.784), as well as 13 lipids were identified to distinguish MDD from BPD with moderate reliability (AUC = 0.860). This study provides further understanding of abnormal lipid metabolism in adult women with MDD and BPD and may develop lipid classifiers able to effectively discriminate MDD from BPD and HC.

Plasma oxysterols in drug-free patients with schizophrenia

Evidence from clinical, genetic, and medical studies has shown the neuronal developmental disorder aspect of schizophrenia (SZ). Whereas oxysterols are vital factors in neurodevelopment, it is still unknown whether they are involved in the pathophysiology of SZ. The current study aims to explore the profile of oxysterols in plasma, ratio to total cholesterol (Tchol) and the association with clinical factors in patients with SZ. Forty men diagnosed with SZ and forty healthy controls matched for age and sex were included in the study. The ratios of cholestane-3β,5α,6β-triol, 27-hydroxycholesterol (27-OHC) and Cholestanol to Tchol increased in the schizophrenic group compared to controls. However, levels of 24S-hydroxycholesterol (24-OHC) were not significantly different between patients and controls. For the SZ patients, the plasma 24-OHC levels were positively correlated with the positive and negative syndrome total scores (PANSS) but negatively correlated with the Montreal Cognitive Assessment scores (MOCA). Moreover, the ratio Cholestanol to Tchol was negatively correlated with MOCA scores and positively correlated with PANSS general. The binary logistic regression analysis revealed that the ratio Cholestane-3β,5α,6β-triol/TChol could be considered as an independent risk factor for SZ. On the other hand, the receiver's operating characteristics analysis corresponding to potential biomarkers on SZ showed Areas Under the Curve (AUCs) of 82.1%; 69.7% and 77.6% for the ratio of Cholestane-3β,5α,6β-triol/TChol, 27-OHC/TChol and Cholestanol/TChol respectively. The relevance of Cholestane-3β,5α,6β-triol, 27-OHC and Cholestanol assays as biomarkers of this disease deserves further investigation.

Mirtazapine in schizophrenia - an undeservedly overlooked option?

Mirtazapine has often been prescribed as add-on treatment for schizophrenia in patients with suboptimal response to conventional treatments. In this review, we evaluate the existing evidence for efficacy and effectiveness of add-on mirtazapine in schizophrenia and reappraise the practical and theoretical aspects of mirtazapine-antipsychotic combinations. In randomized controlled trials (RCTs), mirtazapine demonstrated favourable effects on negative and cognitive (although plausibly not depressive) symptoms, with no risk of psychotic exacerbation. Mirtazapine also may have a desirable effect on antipsychotic-induced sexual dysfunction, but seems not to alleviate extrapyramidal symptoms, at least if combined with second-generation antipsychotics. It is noteworthy that all published RCTs have been underpowered and relatively short in duration. In the only large pragmatic effectiveness study that provided analyses by add-on antidepressant, only mirtazapine was associated with both decreased rate of hospital admissions and number of in-patient days. Mirtazapine hardly affects the pharmacokinetics of antipsychotics. However, possible pharmacodynamic interactions (sedation and metabolic offence) should be borne in mind. The observed desired clinical effects of mirtazapine may be due to its specific receptor-blocking properties. Alternative theoretical explanations include its possible neuroprotective effect. Further well-designed RCTs and real-world effectiveness studies are needed to determine whether add-on mirtazapine should be recommended for difficult-to-treat schizophrenia.

Drugs Interfering with Insulin Resistance and Their Influence on the Associated Hypermetabolic State in Severe Burns: A Narrative Review

It has become widely accepted that insulin resistance and glucose hypermetabolism can be linked to acute pathologies, such as burn injury, severe trauma, or sepsis. Severe burns can determine a significant increase in catabolism, having an important effect on glucose metabolism and on muscle protein metabolism. It is imperative to acknowledge that these alterations can lead to increased mortality through organ failure, even when the patients survive the initial trauma caused by the burn. By limiting the peripheral use of glucose with consequent hyperglycemia, insulin resistance determines compensatory increased levels of insulin in plasma. However, the significant alterations in cellular metabolism lead to a lack of response to insulin's anabolic functions, as well as to a decrease in its cytoprotective role. In the end, via pathological insulin signaling associated with increased liver gluconeogenesis, elevated levels of glucose are detected in the blood. Several cellular mechanisms have been incriminated in the development of insulin resistance in burns. In this context, the main aim of this review article is to summarize some of the drugs that might interfere with insulin resistance in burns, taking into consideration that such an approach can significantly improve the prognosis of the burned patient.

Metabolic indices in schizophrenia: Association of negative symptoms with higher HDL cholesterol in female patients

OBJECTIVES

Negative symptoms of schizophrenia can be related to metabolic abnormalities. The study aimed to assess negative symptoms using the Positive and Negative Syndrome Scale (PANSS) and the Brief Negative Symptoms Scale (BNSS), and their relationship with body mass index (BMI) and lipid indices, in male and female schizophrenic patients.

METHODS

Fifty chronic schizophrenia patients (29 males, 21 females) were included. They have mild to moderate severity of the illness (total PANSS score <80), and received unchanged pharmacological treatment in the last three weeks. Psychopathology symptoms were assessed using the PANSS and BNSS. The measurements of BMI and serum lipids were done in all patients.

RESULTS

In female patients, a significant positive correlation between the intensity of negative symptoms measured by the PANSS and BNSS scales and the concentration of high-density lipoprotein (HDL) cholesterol, and a trend for negative correlation with BMI was observed. Such correlations were not found in male patients.

CONCLUSIONS

Assessing the negative symptoms of schizophrenia, and investigating the relationship of these symptoms with metabolic indices, we showed distinctive features in male and female schizophrenia patients. The positive correlation between negative symptoms and HDL cholesterol in female patients needs to be confirmed in further studies.

Metabolomics-based understanding of the olanzapine-induced weight gain in female first-episode drug-naïve patients with schizophrenia

Previous studies have demonstrated that patients with schizophrenia (SZ) have greater rate of metabolic disorder as compared with the control population, which likely be the consequence of use of atypical antipsychotics. Olanzapine is a widely used antipsychotic, which increases the weight of SZ patients. However, the underlying mechanism remains poorly understood. Here we report the metabolomics-based understanding of the weight gain induced by olanzapine. 57 first-episode drug-naïve patients (FEDN) were recruited, of whom 27 patients completed a 4-week clinical trial. We then profiled the metabolomes of their plasma with the LC-MS-based nontargeted metabolomics approach at the baseline and after olanzapine monotherapy for 4 weeks. We observed that the plasma of the olanzapine-treated patient had significantly higher lysophosphatidylcholine (LysoPC), lysophosphatidylethanolamine (LysoPE) and lower carnitine as compared with that of the baseline plasma samples. Moreover, regression analyses indicated that the change of LysoPC(14:0) level was an independent contributor to the olanzapine-induced weight gain. Our study suggests that the metabolomics-based approach may facilitate the identification of biomarkers associated with the metabolic disorder causing by antipsychotic in schizophrenia patients.

Exercise and Worsening of Extrapyramidal Symptoms during Treatment with Long-Acting Injectable Antipsychotics

Second-generation antipsychotic medications are used to treat schizophrenia and a range of other psychotic disorders, although adverse effects, including cardiovascular and metabolic abnormalities and extrapyramidal symptoms, are often inevitable. Studies have shown that exercise, as an adjunct therapy, can be effective in reducing the core symptoms of schizophrenia as well as ameliorating intrinsic and antipsychotic-induced cardiometabolic abnormalities. However, it is noteworthy that exercise may need to be implemented with caution in some individuals receiving certain antipsychotic treatment regimens. We report here two cases of exercise-associated worsening of extrapyramidal symptoms in two individuals with schizoaffective disorder treated with a long-acting injectable antipsychotic medication over the course of a 12-week exercise program. This worsening of extrapyramidal symptoms can be attributed to an increase in blood flow to the site of injection during exercise, accelerating the rate of absorption and bioavailability of the antipsychotic medication and subsequently increasing dopamine D₂ receptor blockade. When monitoring drug therapy for patients receiving long-acting injectable antipsychotic medications, pharmacists and other healthcare professionals need to consider exercise as a contributing factor for the emergence of extrapyramidal symptoms.

Shorter Chain Triglycerides Are Negatively Associated with Symptom Improvement in Schizophrenia

Schizophrenia is a serious mental disorder requiring lifelong treatment. While medications are available that are effective in treating some patients, individual treatment responses can vary, with some patients exhibiting resistance to one or multiple drugs. Currently, little is known about the causes of the difference in treatment response observed among individuals with schizophrenia, and satisfactory markers of poor response are not available for clinical practice. Here, we studied the changes in the levels of 322 blood plasma lipids between two time points assessed in 92 individuals diagnosed with schizophrenia during their inpatient treatment and their association with the extent of symptom improvement. We found 20 triglyceride species increased in individuals with the least improvement in Positive and Negative Syndrome Scale (PANSS) scores, but not in those with the largest reduction in PANSS scores. These triglyceride species were distinct from the rest of the triglyceride species present in blood plasma. They contained a relatively low number of carbons in their fatty acid residues and were relatively low in abundance compared to the principal triglyceride species of blood plasma.

A comparison of the metabolic side-effects of the second-generation antipsychotic drugs risperidone and paliperidone in animal models

BACKGROUND

The second generation antipsychotic drugs represent the most common form of pharmacotherapy for schizophrenia disorders. It is now well established that most of the second generation drugs cause metabolic side-effects. Risperidone and its active metabolite paliperidone (9-hydroxyrisperidone) are two commonly used antipsychotic drugs with moderate metabolic liability. However, there is a dearth of preclinical data that directly compares the metabolic effects of these two drugs, using sophisticated experimental procedures. The goal of the present study was to compare metabolic effects for each drug versus control animals.

METHODS

Adult female rats were acutely treated with either risperidone (0.1, 0.5, 1, 2, 6 mg/kg), paliperidone (0.1, 0.5, 1, 2, 6 mg/kg) or vehicle and subjected to the glucose tolerance test; plasma was collected to measure insulin levels to measure insulin resistance with HOMA-IR. Separate groups of rats were treated with either risperidone (1, 6 mg/kg), paliperidone (1, 6 mg/kg) or vehicle, and subjected to the hyperinsulinemic euglycemic clamp.

RESULTS

Fasting glucose levels were increased by all but the lowest dose of risperidone, but only with the highest dose of paliperidone. HOMA-IR increased for both drugs with all but the lowest dose, while the three highest doses decreased glucose tolerance for both drugs. Risperidone and paliperidone both exhibited dose-dependent decreases in the glucose infusion rate in the clamp, reflecting pronounced insulin resistance.

CONCLUSIONS

In preclinical models, both risperidone and paliperidone exhibited notable metabolic side-effects that were dose-dependent. Differences between the two were modest, and most notable as effects on fasting glucose.

A Focused Review of the Metabolic Side-Effects of Clozapine

The second generation antipsychotic drug clozapine represents the most effective pharmacotherapy for treatment-resistant psychosis. It is also associated with low rates of extrapyramidal symptoms and hyperprolactinemia compared to other antipsychotic drugs. However, clozapine tends to be underutilized in clinical practice due to a number of disabling and serious side-effects. These are characterized by a constellation of metabolic side-effects which include dysregulation of glucose, insulin, plasma lipids and body fat. Many patients treated with clozapine go on to develop metabolic syndrome at a higher rate than the general population, which predisposes them for Type 2 diabetes mellitus and cardiovascular disease. Treatments for the metabolic side-effects of clozapine vary in their efficacy. There is also a lack of knowledge about the underlying physiology of how clozapine exerts its metabolic effects in humans. In the current review, we focus on key studies which describe how clozapine affects each of the main symptoms of the metabolic syndrome, and cover some of the treatment options. The clinical data are then discussed in the context of preclinical studies that have been conducted to identify the key biological substrates involved, in order to provide a better integrated overview. Suggestions are provided about key areas for future research to better understand how clozapine causes metabolic dysregulation.

Brain-Specific Oxysterols and Risk of Schizophrenia in Clinical High-Risk Subjects and Patients With Schizophrenia

Accumulating evidence from clinical, genetic, and epidemiologic studies suggest that schizophrenia might be a neuronal development disorder. While oxysterols are important factors in neurodevelopment, it is unknown whether oxysterols might be involved in development of schizophrenia. The present study investigated the relationship between tissue-specifically originated oxysterols and risk of schizophrenia. A total of 216 individuals were recruited in this study, including 76 schizophrenia patients, 39 clinical high-risk (CHR) subjects, and 101 healthy controls (HC). We investigated the circulating levels of brain-specific oxysterol 24(S)-hydroxycholesterol (24OHC) and peripheral oxysterol 27-hydroxycholesterol (27OHC) in all participants and analyzed the potential links between the oxysterols and specific clinical symptoms in schizophrenic patients and CHR. Our data showed an elevation of 24OHC in both schizophrenia patients and CHR than that in HC, while a lower level of 27OHC in the schizophrenia group only. The ratio of 24OHC to 27OHC was only increased in the schizophrenic group compared with CHR and HC. For the schizophrenic patients, the circulating 24OHC levels are significantly associated with disease duration, positively correlated with the positive and negative syndrome total scores, while the 27OHC levels were inversely correlated with the positive symptom scores. Together, our data demonstrated the disruption of tissue-specifically originated cholesterol metabolism in schizophrenia and CHR, suggesting the circulating 24OHC or 24OHC/27OHC ratio might not only be a potential indicator for risk for schizophrenia but also be biomarkers for functional abnormalities in neuropathology of schizophrenia.

Crosstalk between Inflammation and the BBB in Stroke

The blood-brain barrier (BBB), which is located at the interface between the central nervous system (CNS) and the circulatory system, is instrumental in establishing and maintaining the microenvironmental homeostasis of the CNS. BBB disruption following stroke promotes inflammation by enabling leukocytes, T cells and other immune cells to migrate via both the paracellular and transcellular routes across the BBB and to infiltrate the CNS parenchyma. Leukocytes promote the removal of necrotic tissues and neuronal recovery, but they also aggravate BBB injury and exacerbate stroke outcomes, especially after late reperfusion. Moreover, the swelling of astrocyte endfeet is thought to contribute to the ‘no-reflow’ phenomenon observed after cerebral ischemia, that is, blood flow cannot return to capillaries after recanalization of large blood vessels. Pericyte recruitment and subsequent coverage of endothelial cells (ECs) alleviate BBB disruption, which causes the transmigration of inflammatory cells across the BBB to be a dynamic process. Furthermore, interneurons and perivascular microglia also make contacts with ECs, astrocytes and pericytes to establish the neurovascular unit. BBB-derived factors after cerebral ischemia triggered microglial activation. During the later stage of injury, microglia remain associated with brain ECs and contribute to repair mechanisms, including postinjury angiogenesis, by acquiring a protective phenotype, which possibly occurs through the release of microglia-derived soluble factors. Taken together, we reviewed dynamic and bidirectional crosstalk between inflammation and the BBB during stroke and revealed targeted interventions based on the crosstalk between inflammation and the BBB, which will provide novel insights for developing new therapeutic strategies.

Predictors of psychosis breakthrough during 24 months of long-acting antipsychotic maintenance treatment in first episode schizophrenia

BACKGROUND

Some patients develop breakthrough psychotic symptoms on antipsychotic maintenance medication (BAMM), despite receiving therapeutic antipsychotic doses to which they previously responded.

METHODS

We examined the occurrence of BAMM in previously minimally treated first-episode patients with schizophrenia-spectrum disorders who were treated according to a standard protocol with a long-acting injectable antipsychotic and regularly assessed over 24 months.

RESULTS

Of 99 patients (age = 24.1 ± 6.5 years, male = 73.7%) who received treatment for ≥6 months (mean follow-up = 20.0 ± 6.5 months) and had responded well to treatment, 21 (21.2%) developed BAMM using operationally defined criteria, after a mean of 17.4 ± 6.1 months. Baseline risk factors for BAMM included lower baseline Positive and Negative Syndrome Scale positive symptoms, poorer quality of life in social relationships and higher blood - high-density lipoprotein-cholesterol. Regarding intra-treatment-factors, BAMM was independently predicted by an increase in low-density lipoprotein-cholesterol and current cannabis use. We did not find a relationship between BAMM and cumulative antipsychotic exposure or dose escalation. While symptoms of the BAMM episode were less severe than during the first episode, the post-BAMM treatment response was poorer than that for the first psychotic episode, suggesting a relationship between BAMM and emergent treatment refractoriness.

CONCLUSIONS

About one in five patients with first-episode schizophrenia developed BAMM during the first two years of treatment, despite assured antipsychotic LAI treatment, indicating that this phenomenon is not restricted to the chronic stages of illness. The role of cannabis use and a possible link between BAMM and blood lipids should be further explored.

The impact of quetiapine on the brain lipidome in a cuprizone-induced mouse model of schizophrenia

The antipsychotic effect of Quetiapine (Que) has been extensively studied and growing evidence suggests that Que has a beneficial effect, improving cognitive functions and promoting myelin repair. However, the effects of Que on the brain lipidome and the association between Que-associated cognitive improvement and changes in lipids remain elusive. In the present study, we assessed the cognitive protective effects of Que treatment and used a mass spectrometry-based lipidomic approach to evaluated changes in lipid composition in the hippocampus, prefrontal cortex (PFC), and striatum in a mouse model of cuprizone (CPZ)-induced demyelination. CPZ induces cognitive impairment and remarkable lipid changes in the brain, specifically in lipid species of glycerophospholipids and sphingolipids. Moreover, the changes in lipid classes of the PFC were more extensive than those observed in the hippocampus and striatum. Notably, Que treatment ameliorated cuprizone-induced cognitive impairment and partly normalized CPZ-induced lipid changes. Taken together, our data suggest that Que may rescue cognitive behavioral changes from CPZ-induced demyelination through modulation of the brain lipidome, providing new insights into the pharmacological mechanism of Que for schizophrenia.

Differential Effects of Acute Treatment With Antipsychotic Drugs on Peripheral Catecholamines

Antipsychotic drugs represent the most effective treatment for chronic psychotic disorders. The newer second generation drugs offer the advantage of fewer neurological side-effects compared to prior drugs, but many cause serious metabolic side-effects. The underlying physiology of these side-effects is not well-understood, but evidence exists to indicate that the sympathetic nervous system may play an important role. In order to examine this possibility further, we treated separate groups of adult female rats acutely with either the first generation antipsychotic drug haloperidol (0.1 or 1 mg/kg) or the second generation drugs risperidone (0.25 or 2.5 mg/kg), clozapine (2 or 20 mg/kg), olanzapine (3 or 15 mg/kg) or vehicle by intraperitoneal injection. Blood samples were collected prior to drug and then 30, 60, 120, and 180 mins after treatment. Plasma samples were assayed by HPLC-ED for levels of norepinephrine, epinephrine, and dopamine. Results confirmed that all antipsychotics increased peripheral catecholamines, although this was drug and dose dependent. For norepinephrine, haloperidol caused the smallest maximum increase (+158%], followed by risperidone (+793%), olanzapine (+952%) and clozapine (+1,684%). A similar pattern was observed for increases in epinephrine levels by haloperidol (+143%], olanzapine (+529%), risperidone (+617%) then clozapine (+806%). Dopamine levels increased moderately with olanzapine [+174%], risperidone [+271%], and clozapine [+430%]. Interestingly, levels of the catecholamines did not correlate strongly with each other prior to treatment at baseline, but were increasingly correlated after treatment as time proceeded. The results demonstrate antipsychotics can potently regulate peripheral catecholamines, in a manner consistent with their metabolic liability.