Adiposity-independent hypoadiponectinemia as a potential marker of insulin resistance and inflammation in schizophrenia patients treated with second generation antipsychotics

Crosstalk between Schizophrenia and Metabolic Syndrome: The Role of Oxytocinergic Dysfunction

The high prevalence of metabolic syndrome in persons with schizophrenia has spurred investigational efforts to study the mechanism beneath its pathophysiology. Early psychosis dysfunction is present across multiple organ systems. On this account, schizophrenia may be a multisystem disorder in which one organ system is predominantly affected and where other organ systems are also concurrently involved. Growing evidence of the overlapping neurobiological profiles of metabolic risk factors and psychiatric symptoms, such as an association with cognitive dysfunction, altered autonomic nervous system regulation, desynchrony in the resting-state default mode network, and shared genetic liability, suggest that metabolic syndrome and schizophrenia are connected via common pathways that are central to schizophrenia pathogenesis, which may be underpinned by oxytocin system dysfunction. Oxytocin, a hormone that involves in the mechanisms of food intake and metabolic homeostasis, may partly explain this piece of the puzzle in the mechanism underlying this association. Given its prosocial and anorexigenic properties, oxytocin has been administered intranasally to investigate its therapeutic potential in schizophrenia and obesity. Although the pathophysiology and mechanisms of oxytocinergic dysfunction in metabolic syndrome and schizophrenia are both complex and it is still too early to draw a conclusion upon, oxytocinergic dysfunction may yield a new mechanistic insight into schizophrenia pathogenesis and treatment.

Adiponectin, leptin and resistin levels in first-episode, drug-naïve patients with psychosis before and after short-term antipsychotic treatment

OBJECTIVE

There is increasing evidence that adiponectin, resistin and leptin may be implicated in the pathophysiology of neuropsychiatric disorders, including schizophrenia. The results of the studies so far remain controversial. Our aim was to compare serum adiponectin, leptin and resistin levels between drug-naïve, first -episode patients with psychosis and healthy controls and in the same group of patients after six weeks of antipsychotic treatment.

METHODS

Forty first-episode patients with psychosis and 40 matched controls were included in the study. Serum levels of adiponectin, resistin and leptin were measured by enzyme linked immunosorbent assay (ELISA) in both groups. In the patient group, the same adipokines were also measured six weeks after the initiation of antipsychotic treatment.

RESULTS

Log-transformed serum levels of adiponectin (mean difference = 1.68, 95% confidence interval [CI] = 1.30 to 2.06, U = 157, p < 0.0001), resistin (0.48, 95% CI = 0.36 to 0.59, t = 8.00, p < 0.0001) and leptin (0.66, 95% CI = 0.52 to 0.80, U = 160, p < 0.0001) were significantly higher to the patient group compared to controls. Leptin levels were significantly decreased in the patient group six weeks after the initiation of antipsychotic treatment (mean change = -0.40, 95% CI = -0.59 to -0.21, W = 666; p < 0.0001) while those of adiponectin and resistin levels did not change significantly.

CONCLUSION

In our study we found higher levels of adiponectin, leptin and resistin in drug-naïve, first-episode patients with normal Body Mass Index (BMI) compared to controls. After six weeks of antipsychotic treatment, there was no change in adiponectin and resistin levels, while leptin levels were reduced compared to baseline.

Adiponectin and Stnfr2 peripheral levels are associated with cardiovascular risk in patients with schizophrenia

OBJECTIVES

To investigate the association between cytokine peripheral levels and the risk of cardiovascular disease in patients with schizophrenia and controls.

METHODS

A sample of 40 patients and 40 control subjects participated in the study. Psychiatric diagnosis was established following structured clinical assessment. The Framingham Score was used to assess cardiovascular risk (CVR). Serum levels of the cytokines IL-1β, IL-6, IL-8, IL-10, IL-12p70 and TNF-α were determined by cytometric bead array (CBA) technique, and the serum levels of IL-33, sST2, sTNFR1, sTNFR2, Leptin and Adiponectin by Enzyme-Linked Immunosorbent assay (ELISA).

RESULTS

Patients with schizophrenia showed greater frequency of moderate CVR when compared with controls (p = 0.14). In addition, patients showed higher levels of sTNFR2 and Adiponectin compared to controls (p = 0.007 and p < 0.001, respectively). Adiponectin and sTNFR2 were associated with CVR only in patients (p = 0.0002 and p = 0.033, respectively). In multivariate analysis controlling for socio-demographic and clinical confounders, illness duration (r = 0.492; p < 0.002) and sTNFR2 (r = 0.665; p < 0.004) were independent predictors of CVR.

CONCLUSION

Our results reinforce the concept that patients with schizophrenia are at greater risk to develop cardiovascular diseases, and suggest that the associated chronic low-grade inflammation might play a role in this process.

A cross-sectional MR study of body fat volumes and distribution in chronic schizophrenia

People with schizophrenia show higher risk for abdominal obesity than the general population, which could contribute to excess mortality. However, it is unclear whether this is driven by alterations in abdominal fat partitioning. Here, we test the hypothesis that individuals with schizophrenia show a higher proportion of visceral to total body fat measured using magnetic resonance imaging (MRI). We recruited 38 participants with schizophrenia and 38 healthy controls matched on age, sex, ethnicity, and body mass index. We found no significant differences in body fat distribution between groups, suggesting that increased abdominal obesity in schizophrenia is not associated with altered fat distribution.

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.

Adipose tissue dysfunction, inflammation, and insulin resistance: alternative pathways to cardiac remodelling in schizophrenia. A multimodal, case-control study

Cardiovascular diseases are the leading cause of death in schizophrenia. Patients with schizophrenia show evidence of concentric cardiac remodelling (CCR), defined as an increase in left-ventricular mass over end-diastolic volumes. CCR is a predictor of cardiac disease, but the molecular pathways leading to this in schizophrenia are unknown. We aimed to explore the relevance of hypertensive and non-hypertensive pathways to CCR and their potential molecular underpinnings in schizophrenia. In this multimodal case-control study, we collected cardiac and whole-body fat magnetic resonance imaging (MRI), clinical measures, and blood levels of several cardiometabolic biomarkers known to potentially cause CCR from individuals with schizophrenia, alongside healthy controls (HCs) matched for age, sex, ethnicity, and body surface area. Of the 50 participants, 34 (68%) were male. Participants with schizophrenia showed increases in cardiac concentricity (d = 0.71, 95% CI: 0.12, 1.30; p = 0.01), indicative of CCR, but showed no differences in overall content or regional distribution of adipose tissue compared to HCs. Despite the cardiac changes, participants with schizophrenia did not demonstrate activation of the hypertensive CCR pathway; however, they showed evidence of adipose dysfunction: adiponectin was reduced (d = -0.69, 95% CI: -1.28, -0.10; p = 0.02), with evidence of activation of downstream pathways, including hypertriglyceridemia, elevated C-reactive protein, fasting glucose, and alkaline phosphatase. In conclusion, people with schizophrenia showed adipose tissue dysfunction compared to body mass-matched HCs. The presence of non-hypertensive CCR and a dysmetabolic phenotype may contribute to excess cardiovascular risk in schizophrenia. If our results are confirmed, acting on this pathway could reduce cardiovascular risk and resultant life-years lost in people with schizophrenia.

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.

Metabolic disturbances associated with antipsychotic drug treatment in patients with schizophrenia: State-of-the-art and future perspectives

Metabolic disturbances and obesity are major cardiovascular risk factors in patients with schizophrenia, resulting in a higher mortality rate and shorter life expectancy compared with those in the general population. Although schizophrenia and metabolic disturbances may share certain genetic or pathobiological risks, antipsychotics, particularly those of second generation, may further increase the risk of weight gain and metabolic disturbances in patients with schizophrenia. This review included articles on weight gain and metabolic disturbances related to antipsychotics and their mechanisms, monitoring guidelines, and interventions. Nearly all antipsychotics are associated with weight gain, but the degree of the weight gain varies considerably. Although certain neurotransmitter receptor-binding affinities and hormones are correlated with weight gain and specific metabolic abnormalities, the precise mechanisms underlying antipsychotic-induced weight gain and metabolic disturbances remain unclear. Emerging evidence indicates the role of genetic polymorphisms associated with antipsychotic-induced weight gain and antipsychotic-induced metabolic disturbances. Although many guidelines for screening and monitoring antipsychotic-induced metabolic disturbances have been developed, they are not routinely implemented in clinical care. Numerous studies have also investigated strategies for managing antipsychotic-induced metabolic disturbances. Thus, patients and their caregivers must be educated and motivated to pursue a healthier life through smoking cessation and dietary and physical activity programs. If lifestyle intervention fails, switching to another antipsychotic drug with a lower metabolic risk or adding adjunctive medication to mitigate weight gain should be considered. Antipsychotic medications are essential for schizophrenia treatment, hence clinicians should monitor and manage the resulting weight gain and metabolic disturbances.

Male-Specific Metabolic Considerations Concerning the Prescription of Second-Generation Antipsychotics to Adolescents

Objectives: Although males and females gain comparable weight when prescribed second-generation antipsychotics (SGAs), males may be uniquely vulnerable to an array of endocrinological, inflammatory, and psychosocial adverse drug effects. Methods: This opinion piece reviews work in each of these three areas for consideration. Results: Androgens may decrease both through hypothalamic-pituitary-gonadal axis dysregulation and as a consequence of increased adiposity. Testosterone has anti-inflammatory properties, and declining levels as well as many other factors may influence overall immunological functioning. Psychosocial stressors are gender specific in obesity, and SGA-induced obesity may affect males in unique and severe ways. Conclusion: This opinion piece supports the framework of the World Federation of Societies of Biological Psychiatry's Task Force on Men's Mental Health to advocate for further studies concerning the adverse drug effects of SGAs as unique manifested in male children, adolescents, and young men.

Impaired hormonal regulation of appetite in schizophrenia: A narrative review dissecting intrinsic mechanisms and the effects of antipsychotics

Cardiometabolic diseases are the main contributor of reduced life expectancy in patients with schizophrenia. It is now widely accepted that antipsychotic treatment plays an important role in the development of obesity and its consequences. However, some intrinsic mechanisms need to be taken into consideration. One of these mechanisms might be related to impaired hormonal regulation of appetite in this group of patients. In this narrative review, we aimed to dissect impairments of appetite-regulating hormones attributable to intrinsic mechanisms and those related to medication effects. Early hormonal alterations that might be associated with intrinsic mechanisms include low levels of leptin and glucagon-like peptide-1 (GLP-1) together with elevated insulin levels in first-episode psychosis (FEP) patients. However, evidence regarding low GLP-1 levels in FEP patients is based on one large study. In turn, multiple-episode schizophrenia patients show elevated levels of insulin, leptin and orexin A together with decreased levels of adiponectin. In addition, patients receiving olanzapine may present with low ghrelin levels. Post mortem studies have also demonstrated reduced number of neuropeptide Y neurons in the prefrontal cortex of patients with schizophrenia. Treatment with certain second-generation antipsychotics may also point to these alterations. Although our understanding of hormonal regulation of appetite in schizophrenia has largely been improved, several limitations and directions for future studies need to be addressed. This is of particular importance since several novel pharmacological interventions for obesity and diabetes have already been developed and translation of these developments to the treatment of cardiometabolic comorbidities in schizophrenia patients is needed.

Role of TRPV1/TRPV3 channels in olanzapine-induced metabolic alteration: Possible involvement in hypothalamic energy-sensing, appetite regulation, inflammation and mesolimbic pathway

Atypical antipsychotics (AAPs) have the tendency of inducing severe metabolic alterations like obesity, diabetes mellitus, insulin resistance, dyslipidemia and cardiovascular complications. These alterations have been attributed to altered hypothalamic appetite regulation, energy sensing, insulin/leptin signaling, inflammatory reactions and active reward anticipation. Line of evidence suggests that transient receptor potential vanilloid type 1 and 3 (TRPV1 and TRPV3) channels are emerging targets in treatment of obesity, diabetes mellitus and could modulate feed intake. The present study was aimed to investigate the putative role TRPV1/TRPV3 in olanzapine-induced metabolic alterations in mice. Female BALB/c mice were treated with olanzapine for six weeks to induce metabolic alterations. Non-selective TRPV1/TRPV3 antagonist (ruthenium red) and selective TRPV1 (capsazepine) and TRPV3 antagonists (2,2-diphenyltetrahydrofuran or DPTHF) were used to investigate the involvement of TRPV1/TRPV3 in chronic olanzapine-induced metabolic alterations. These metabolic alterations were differentially reversed by ruthenium red and capsazepine, while DPTHF didn't show any significant effect. Olanzapine treatment also altered the mRNA expression of hypothalamic appetite-regulating and nutrient-sensing factors, inflammatory genes and TRPV1/TRPV3, which were reversed with ruthenium red and capsazepine treatment. Furthermore, olanzapine treatment also increased expression of TRPV1/TRPV3 in nucleus accumbens (NAc), TRPV3 expression in ventral tegmental area (VTA), which were reversed by the respective antagonists. However, DPTHF treatment showed reduced feed intake in olanzapine treated mice, which might be due to TRPV3 specific antagonism and reduced hedonic feed intake. In conclusion, our results suggested the putative role TRPV1 in hypothalamic dysregulations and TRPV3 in the mesolimbic pathway; both regulate feeding in olanzapine treated mice.

Efficacy and safety of brexpiprazole in acute management of psychiatric disorders: a meta-analysis of randomized controlled trials

Brexpiprazole is a new atypical antipsychotic for schizophrenia management and as adjunct in major depressive disorder (MDD). We searched randomized controlled trials (RCT) to review brexpiprazole efficacy and tolerability in acute management of schizophrenia and MDD using PubMed, EUDRACT, ClinicalTrials.gov and Cochrane Central Register of Controlled Trials. A meta-analysis was conducted using the identified 14 RCT to assess its efficacy using positive and negative syndrome scale (PANSS), clinical global impressions - severity of illness (CGI-S), personal and social performance scale (PSP), Montgomery-Åsberg depression rating scale (MADRS), Sheehan disability scale (SDS) and Hamilton depression rating scale (HDRS17). The mean difference comparing brexpiprazole and placebo were PANSS -4.48, CGI-S -0.23 and PSP 3.24 favoring brexpiprazole. Compared to aripiprazole and quetiapine, brexpiprazole showed similar efficacy. In MDD, brexpiprazole showed efficacy compared to placebo demonstrated by MADRS -1.25, SDS -0.37 and HDRS17 -1.28. Brexpiprazole was associated with side effects including akathisia risk ratio (RR) = 1.72; weight increase RR = 2.74 and somnolence RR = 1.87. Compared to 4 mg, brexpiprazole 2 mg was associated with less risk of akathisia and somnolence. Brexpiprazole demonstrated significant improvements in schizophrenia and MDD and is well-tolerated; however, associated with akathisia and somnolence. These findings will guide psychiatrists and pharmacists in their clinical role for supporting psychiatric patients care.

Berberine attenuated olanzapine-induced metabolic alterations in mice: Targeting transient receptor potential vanilloid type 1 and 3 channels

Transient receptor potential vanilloid type 1 (TRPV1) channels are emerging therapeutic targets for metabolic disorders. Berberine, which is a modulator of TRPV1, has proven antiobesity and antidiabetic potentials. The present study was aimed to investigate the protective effects of berberine in olanzapine-induced alterations in hypothalamic appetite control, inflammation and metabolic aberrations in mice targeting TRPV1 channels. Female BALB/c mice (18-23 g) were treated with olanzapine (6 mg/kg, p.o.) for six weeks to induce metabolic alterations, while berberine (100 and 200 mg/kg, p.o.) and metformin (100 mg/kg, p.o) were used as test and standard interventions respectively. Weekly assessment of feed-water intake, body temperature and body weight was done, while locomotion was measured at the end of week 1 and 6. Serum glucose and lipid profile were assessed by biochemical methods, while other serum biomarkers were assessed by ELISA. qPCR was used to quantify the mRNA expression in the hypothalamus. Olanzapine treatment significantly increased the feed intake, weight gain, adiposity index, while reduced body temperature and locomotor activity which were reversed by berberine treatment. Berberine treatment reduced serum ghrelin and leptin levels as well decrease in hypothalamic mRNA expression of orexigenic neuropeptides, inflammatory markers and ghrelin receptor in olanzapine-treated mice. Olanzapine treatment increased expression of TRPV1/TRPV3 in the hypothalamus which was significantly decreased by berberine treatment. Our results suggest that berberine, by TRPV1/TRPV3 modulation, attenuated the olanzapine-induced metabolic alterations in mice. Hence berberine supplementation in psychiatric patients could be a preventive approach to reduce the metabolic adverse effects of antipsychotics.

The Novel Perspectives of Adipokines on Brain Health

First seen as a fat-storage tissue, the adipose tissue is considered as a critical player in the endocrine system. Precisely, adipose tissue can produce an array of bioactive factors, including cytokines, lipids, and extracellular vesicles, which target various systemic organ systems to regulate metabolism, homeostasis, and immune response. The global effects of adipokines on metabolic events are well defined, but their impacts on brain function and pathology remain poorly defined. Receptors of adipokines are widely expressed in the brain. Mounting evidence has shown that leptin and adiponectin can cross the blood–brain barrier, while evidence for newly identified adipokines is limited. Significantly, adipocyte secretion is liable to nutritional and metabolic states, where defective circuitry, impaired neuroplasticity, and elevated neuroinflammation are symptomatic. Essentially, neurotrophic and anti-inflammatory properties of adipokines underlie their neuroprotective roles in neurodegenerative diseases. Besides, adipocyte-secreted lipids in the bloodstream can act endocrine on the distant organs. In this article, we have reviewed five adipokines (leptin, adiponectin, chemerin, apelin, visfatin) and two lipokines (palmitoleic acid and lysophosphatidic acid) on their roles involving in eating behavior, neurotrophic and neuroprotective factors in the brain. Understanding and regulating these adipokines can lead to novel therapeutic strategies to counteract metabolic associated eating disorders and neurodegenerative diseases, thus promote brain health.

Adipose tissue as a target for second-generation (atypical) antipsychotics: A molecular view

Schizophrenia is a neuropsychiatric disorder that chronically affects 21 million people worldwide. Second-generation antipsychotics (SGAs) are the cornerstone in the management of schizophrenia. However, despite their efficacy in counteracting both positive and negative symptomatology of schizophrenia, recent clinical observations have described an increase in the prevalence of metabolic disturbances in patients treated with SGAs, including abnormal weight gain, hyperglycemia and dyslipidemia. While the molecular mechanisms responsible for these side-effects remain poorly understood, increasing evidence points to a link between SGAs and adipose tissue depots of white, brown and beige adipocytes. In this review, we survey the present knowledge in this area, with a particular focus on the molecular aspects of adipocyte biology including differentiation, lipid metabolism, thermogenic function and the browning/beiging process.

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.

Adipokine levels are associated with insulin resistance in antipsychotics users independently of BMI

BACKGROUND

The prevalence of obesity, metabolic syndrome and type 2 diabetes mellitus is increased among patients with severe mental disorders, and particularly use of second generation antipsychotic drugs is associated with metabolic side effects. Antipsychotics have been found to alter levels of adipokines which regulate insulin sensitivity, but their role in antipsychotic-associated insulin resistance is not established, and it is unclear whether adipokines affect insulin resistance independently of body mass index (BMI).

METHODS

We included 1050 patients with severe mental disorders and 112 healthy controls aged 18-65 years from the Oslo area, Norway. Clinical variables, BMI and use of medication were assessed, fasting blood samples were obtained for calculation of the leptin/adiponectin ratio (L/A ratio) and estimate of insulin resistance using the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). Case-control analyses were followed by mediation analyses to evaluate the possible direct effect of antipsychotics on HOMA-IR and indirect effect mediated via the L/A ratio. This was performed both with and without adjustment for BMI, in the total sample and in an antipsychotic monotherapy subsample (N = 387).

RESULTS

BMI, L/A ratio and HOMA-IR were significantly higher in patients than controls (p < 0.001-p = 0.01). There was a significant direct effect from use of antipsychotics in general on HOMA-IR both without (b = 0.03, p = 0.007) and with adjustment for BMI (b = 0.03, p = 0.013), as well as a significant mediating effect via L/A ratio both without (b = 0.03, p < 0.001) and with adjustment for BMI (b = 0.01, p = 0.041). Use of olanzapine (b = 0.03, p < 0.001) or aripiprazole (b = 0.04, p < 0.001) in monotherapy showed significant effects on HOMA-IR mediated via L/A ratio.

CONCLUSIONS

The study suggests that use of antipsychotics may alter adipokine levels, and that increased L/A ratio may play a role in the development of insulin resistance associated with use of antipsychotics also independently of BMI.

Atypical antipsychotics-induced metabolic syndrome and nonalcoholic fatty liver disease: a critical review

The atypical antipsychotics (AAPs) have been used as first-line drugs in psychiatric practice for a wide range of psychotic disorders, including schizophrenia and bipolar mania. While effectively exerting therapeutic effects on positive and negative symptoms, as well as cognitive impairments in schizophrenia patients, these drugs are less likely to induce extrapyramidal symptoms compared to typical antipsychotics. However, the increasing application of them has raised questions on their tolerability and adverse effects over the endocrine, metabolic, and cardiovascular axes. Specifically, AAPs are associated to different extents, with weight gain, metabolic syndrome (MetS), and nonalcoholic fatty liver disease (NAFLD). This article summarized clinical evidence showing the metabolic side effects of AAPs in patients with schizophrenia, and experimental evidence of AAPs-induced metabolic side effects observed in animals and cell culture studies. In addition, it discussed potential mechanisms involved in the APPs-induced MetS and NAFLD.

Antipsychotics-induced metabolic alterations: Recounting the mechanistic insights, therapeutic targets and pharmacological alternatives

Atypical antipsychotics (AAPs) are the drug of choice in the management of mental illnesses by virtue of their advantage over typical antipsychotics i.e. least tendency of producing extrapyramidal motor symptoms (EPS) or pseudoparkinsonism. Despite the clinical efficacy, AAPs produces troublesome adverse effects, particularly hyperphagia, hyperglycemia, dyslipidemia weight gain, diabetes mellitus, insulin resistance and QT prolongation which further develops metabolic and cardiac complications with subsequent reduction in life expectancy, poor patient compliance, and sudden death. AAPs-induced weight gain and metabolic alterations are increasing at an alarming rate and became an utmost matter of concern for psychopharmacotherapy. Diverse underlying mechanisms have been explored such as the interaction of AAPs with neurotransmitter receptors, alteration in food reward anticipation behavior, altered expressions of hypothalamic orexigenic and anorexigenic neuropeptides, histamine H₁ receptor-mediated hypothalamic AMP-activated protein kinase (AMPK) activation, increased blood leptin, ghrelin, pro-inflammatory cytokines. Antipsychotics induced imbalance in energy homeostasis, reduction in energy expenditure which is linked to altered expression of uncoupling proteins (UCP-1) in brown adipose tissue and reduced hypothalamic orexin expressions are emerging insights. In addition, alteration in gut-microbiota and subsequent inflammation, dyslipidemia, obesity, and diabetes after AAPs treatment are also associated with weight gain and metabolic alterations. Oral hypoglycemics and lipid-lowering drugs are mainly prescribed in the clinical management of weight gain associated with AAPs while many other pharmacological and nonpharmacological interventions also have been explored in different clinical and preclinical studies. In this review, we critically discuss the current scenario, mechanistic insights, biomarkers, and therapeutic alternatives for metabolic alterations associated with antipsychotics.

Mechanisms underlying metabolic disturbances associated with psychosis and antipsychotic drug treatment

The increase in cardiovascular disease and reduced life expectancy in schizophrenia likely relate to an increased prevalence of metabolic disturbances. Such metabolic risk factors in schizophrenia may result from both symptom-related effects and aetiological factors. However, a major contributory factor is that of treatment with antipsychotic drugs. These drugs differ in effects on body weight; the underlying mechanisms are not fully understood and may vary between drugs, but may include actions at receptors associated with the hypothalamic control of food intake. Evidence supports 5-hydroxytryptamine receptor 2C and dopamine D2 receptor antagonism as well as antagonism at histamine H1 and muscarinic M3 receptors. These M3 receptors may also mediate the effects of some drugs on glucose regulation. Several antipsychotics showing little propensity for weight gain, such as aripiprazole, have protective pharmacological mechanisms, rather than just the absence of a hyperphagic effect. In addition to drug differences, there is large individual variation in antipsychotic drug-induced weight gain. This pharmacogenetic association reflects genetic variation in several drug targets, including the 5-hydroxytryptamine receptor 2C, as well as genes involved in obesity and metabolic disturbances. Thus predictive genetic testing for drug-induced weight gain would represents a first step towards personalised medicine addressing this severe and problematic iatrogenic disease.