Atypical antipsychotics and the neural regulation of food intake and peripheral metabolism

The dosage-dependent effects of cevimeline in preventing clozapine-induced dyslipidaemia in female rats

Clozapine is the most effective second-generation antipsychotic drug, especially for the therapy of treatment-resistant schizophrenia. However, it is associated with metabolic side-effects. Clozapine has a high antagonistic affinity to muscarinic M3 receptors, which has been reported to play a significant role in these side-effects. This study aimed to investigate whether co-administration of cevimeline (an M3 receptor agonist) could prevent the metabolic disorders induced by clozapine. Female Sprague Dawley rats were treated orally with clozapine (20 mg/kg, 3 times daily) and/or cevimeline at three dosages (3, 6, 9 mg/kg, 3 times daily), or a vehicle for two weeks. Body weight gain, food/water intake, and temperature were recorded. Open field tests were performed to assess motor activity. Clozapine only treatment significantly decreased body weight gain, feeding efficiency, perirenal, periovary, inguinal, total white fat mass, and NEFA levels. The reduction in body weight gain and feeding efficiency caused by clozapine was partially reversed by co-treatment with 3 or 6 mg/kg cevimeline. Clozapine also significantly increased the liver mass, LDL, and HDL level, which were reversed by the co-treatment with cevimeline at all tested dosages. These results support further clinical trials to evaluate cevimeline's potential in controlling clozapine-induced dyslipidemia.

Exploring the therapeutic potential of chlorogenic acid in alleviating olanzapine-induced metabolic syndrome in rats: a key role of hypothalamic satiety proteins

Objectives: Olanzapine (Olz) is an effective antipsychotic medication for schizophrenia; however, its use is associated with weight gain and metabolic disorders. Chlorogenic acid (CGA), a dietary polyphenol, has a promising potential for the treatment of obesity, diabetes, and hypertension. This study aimed to determine whether CGA could effectively manage Olz-induced metabolic syndrome (MetS) in a rat model, with metformin (Met) as a positive control.Methods: Female Wistar rats were divided into seven groups: control; Olz (5 mg/kg/day, IP); CGA (20, 40, and 80 mg/kg/day, gavage) plus Olz; Met (100 mg/kg/day, gavage) plus Olz; and CGA (80 mg/kg/day, gavage) for 30 days. Metabolic parameters including body weight, fasting blood glucose, triglycerides, and blood pressure were assessed. This study focused on evaluating serum levels of leptin and adiponectin, as well as hypothalamic protein expression of pro-opiomelanocortin (POMC), neuropeptide Y (NPY), AMP-activated protein kinase (AMPK), and 5-HT2C receptors (5-HT2CR), which are known to influence energy balance and potentially play a role in Olz-induced metabolic abnormalities.Results: Olz caused substantial hyperphagia, weight gain, hypertension, and liver damage, along with elevated fasting blood glucose, triglycerides, and leptin levels. CGA and Met mitigated these effects, although Olz-induced elevation of adiponectin levels remained unaffected by either treatment. Mechanistically, Olz reduced 5-HT2CR protein levels, a trend that was observed in the CGA and Met therapy groups. Olz also enhanced NPY protein levels and the pAMPK/AMPK ratio while lowering POMC protein levels. These alterations were reversed in rats administered CGA or Met.Discussion: These findings suggest that CGA effectively attenuated the adverse metabolic consequences of Olz by modulating leptin, NPY, POMC, and AMPK protein levels. CGA's therapeutic potential highlights its potential as a dietary intervention for managing antipsychotic-induced metabolic disturbances.

Targeting histamine in metabolic syndrome: Insights and therapeutic potential

Metabolic syndrome is a complex disorder defined by a cluster of interconnected factors including obesity, insulin resistance, hypertension, hyperlipidemia and hyperglycemia which increase the risk of cardiovascular disease, non-alcoholic fatty liver disease, type 2 diabetes mellitus and other related diseases. Histamine, as a biogenic amine, participates in various physiological processes. Increasing evidence suggests histamine plays critical roles in Metabolic syndrome as well as its associated diseases by interacting with four histamine receptors. In this review, we summarize the functions and mechanisms of histamine in Metabolic syndrome, indicating histamine as a possible target in treating Metabolic syndrome and its associated diseases.

Investigating the Impacts of Diet, Supplementation, Microbiota, Gut-Brain Axis on Schizophrenia: A Narrative Review

Schizophrenia is a disease with a complex etiology that significantly impairs the functioning of patients. In recent years, there has been increasing focus on the importance of the gut microbiota in the context of the gut-brain axis. In our study, we analyzed data on the gut-brain axis in relation to schizophrenia, as well as the impacts of eating habits, the use of various supplements, and diets on schizophrenia. Additionally, the study investigated the impact of antipsychotics on the development of metabolic disorders, such as diabetes, dyslipidemia, and obesity. There may be significant clinical benefits to be gained from therapies supported by supplements such as omega-3 fatty acids, B vitamins, and probiotics. The results suggest the need for a holistic approach to the treatment of schizophrenia, incorporating both drug therapy and dietary interventions.

Risk evaluation of diabetic ketoacidosis associated with antipsychotics among patients with schizophrenia in the Japanese adverse event report database

OBJECTIVE

Diabetic ketoacidosis (DKA) is a serious life-threatening condition and can be associated with antipsychotic medication. Asian patients with diabetes exhibit less insulin resistance than Caucasians; however, all previous studies concerning antipsychotic-related DKA have been conducted in Western populations. We analyzed the rank order of the association of antipsychotic agents for schizophrenia with DKA using the Japanese Adverse Drug Event Report database, a spontaneous reporting system database.

METHODS

We performed a retrospective pharmacovigilance disproportionality analysis using adverse event reports submitted to the Pharmaceuticals and Medical Devices Agency between April 2004 and March 2021. The study population comprised 7435 patients with schizophrenia, and the total number of antipsychotic-related DKA reports was 55.

RESULTS

Among the 55 cases of DKA in patients with schizophrenia, 6% (3/55) patients died after DKA. The signals of DKA were reported after treatment with olanzapine, with a significant adjusted reporting odds ratio (95% CI) of 3.26 (1.87-5.66). In 1399 olanzapine treatment cases, multivariable logistic regression analysis using a forward selection method showed that being male (adjusted RORs 2.72 (1.07-6.90)) was associated with the onset of DKA.

CONCLUSION

Our study revealed that treatment with olanzapine was associated with the development of DKA among patients with schizophrenia. The results also clarified that male patients were at higher risk for DKA among patients treated with olanzapine. The application of these data will aid in risk monitoring and management that may reduce the occurrence of antipsychotic-related DKA in treatment for schizophrenia.

Mechanism and treatments of antipsychotic-induced weight gain

The long-term use of antipsychotics (APs) may cause a variety of diseases, such as metabolic syndrome, antipsychotic-induced weight gain (AIWG), and even obesity. This paper reviews the various mechanisms of AIWG and obesity in detail, involving genetics, the central nervous system, the neuroendocrine system, and the gut microbiome. The common drug and non-drug therapies used in clinical practice are also introduced, providing the basis for research on the molecular mechanisms and the future selection of treatments.

Acute and sub-chronic toxicological evaluation of Averrhoa carambola leaves in Sprague Dawley rats

Averrhoa carambola is a species of tree native to tropical Southeast Asia. It possesses antioxidant and anti-hyperlipidemia effects and has traditionally been used to treat a variety of ailments. However, the presence of oxalic acid in its fruits might restrict its consumption by individuals suffering from kidney disease, and caramboxin can cause neurotoxicity. In this study, we evaluated the acute and sub-chronic toxicity of the methanolic extract of A. carambola leaves (MEAC) in male and female rats. In the acute study, female rats were given a single oral dose of 5000 mg/kg of MEAC and closely examined for distinct indications of toxic effects during the first 4 h, periodically for 48 h, and daily thereafter for 14 days. Rats of both sexes were employed in the sub-chronic investigation for the 28-day repeated dose oral toxicity study. Results of the acute study revealed the safety of MEAC up to a dose of 5000 mg/kg where the rats did not show changes or signs of toxicity. In the sub-chronic toxicity study, MEAC (250, 500, and 1000 mg/kg) administration did not affect the body weight, food, and water consumption, motor coordination, behavior, or mental alertness in the treated rats. In addition, no variations in hematological or biochemical markers were found in MEAC-treated rats. In conclusion, these findings pinpoint the safety of MEAC at doses up to 5000 mg/kg. The leaves of A. carambola could be safely consumed by people with kidney disease to treat other ailments.

Olanzapine-induced lipid disturbances: A potential mechanism through the gut microbiota-brain axis

Objective: Long-term use of olanzapine can induce various side effects such as lipid metabolic disorders, but the mechanism remains to be elucidated. The gut microbiota-brain axis plays an important role in lipid metabolism, and may be related to the metabolic side effects of olanzapine. Therefore, we explored the mechanism by which olanzapine-induced lipid disturbances through the gut microbiota-brain axis.

Methods: Sprague Dawley rats were randomly divided into two groups, which underwent subphrenic vagotomy and sham surgery. Then the two groups were further randomly divided into two subgroups, one was administered olanzapine (10 mg/kg/day) by intragastric administration, and the other was administered normal saline by intragastric administration (4 ml/kg/day) for 2 weeks. The final changes in lipid parameters, gut microbes and their metabolites, and orexin-related neuropeptides in the hypothalamus were investigated among the different groups.

Results: Olanzapine induced lipid disturbances as indicated by increased weight gain, elevated ratio of white adipose tissue to brown adipose tissue, as well as increased triglyceride and total cholesterol. Olanzapine also increased the Firmicutes/Bacteroides (F/B) ratio in the gut, which was even aggravated by subphrenic vagotomy. In addition, olanzapine reduced the abundance of short-chain fatty acids (SCFAs) metabolism related microbiome and 5-hydroxytryptamine (5-HT) levels in the rat cecum, and increased the gene and protein expression of the appetite-related neuropeptide Y/agouti-related peptide (NPY/AgRP) in the hypothalamus.

Conclusion: The abnormal lipid metabolism caused by olanzapine may be closely related to the vagus nerve-mediated gut microbiota-brain axis.

Activation of the aryl hydrocarbon receptor by clozapine induces preadipocyte differentiation and contributes to endothelial dysfunction

BACKGROUND

The superior therapeutic benefit of clozapine is often associated with metabolic disruptions as obesity, insulin resistance, tachycardia, higher blood pressure, and even hypertension.

AIMS

These adverse vascular/ metabolic events under clozapine are similar to those caused by polycyclic aromatic hydrocarbons (PAHs), and clozapine shows structural similarity to well-known ligands of the aryl hydrocarbon receptor (AhR). Therefore, we speculated that the side effects caused by clozapine might rely on AhR signaling.

METHODS

We examined clozapine-induced AhR activation by luciferase reporter assays in hepatoma HepG2 cells and we proved upregulation of the prototypical AhR target gene Cyp1A1 by realtime-PCR (RT-PCR) analysis and enzyme activity. Next we studied the physiological role of AhR in clozapine's effects on human preadipocyte differentiation and on vasodilatation by myography in wild-type and AhR-/- mice.

RESULTS

In contrast to other antipsychotic drugs (APDs), clozapine triggered AhR activation and Cyp1A1 expression in HepG2 cells and adipocytes. Clozapine induced adipogenesis via AhR signaling. After PGF2α-induced constriction of mouse aortic rings, clozapine strongly reduced the maximal vasorelaxation under acetylcholine in rings from wild-type mice, but only slightly in rings from AhR-/- mice. The reduction was also prevented by pretreatment with the AhR antagonist CH-223191.

CONCLUSION

Identification of clozapine as a ligand for the AhR opens new perspectives to explain common clozapine therapy-associated adverse effects at the molecular level.

Chronic neuroleptic treatment combined with a high fat diet elevated [3H] flunitrazepam binding in the cerebellum

Clinical and preclinical studies have shown dysfunctions in genetic expression and neurotransmission of γ-Aminobutyric acid (GABA), GABA_A receptor subunits, and GABA-synthesizing enzymes GAD₆₇ and GAD₆₅ in schizophrenia. It is well documented that there is significant weight gain after chronic neuroleptic treatment in humans. While there are limited studies on the effects of diet on GABA signaling directly, a change in diet has been used clinically as an adjunct to treatment for schizophrenic relief. In this study, rats chronically consumed either a chow diet (CD) or a 60% high-fat diet (HFD) and drank from bottles that contained one of the following solutions: water, haloperidol (1.5 mg/kg), or olanzapine (10 mg/kg) for four weeks. Rats were then euthanized and their brains were processed for GABA_A in-vitro receptor autoradiography using [³H] flunitrazepam. A chronic HFD treatment yielded significantly increased [³H] flunitrazepam binding in the rat cerebellum independent of neuroleptic treatment. The desynchronization between the prefrontal cortex and the cerebellum is associated with major cognitive and motor dysfunctions commonly found in schizophrenic symptomatology, such as slowed reaction time, motor dyscoordination, and prefrontal activations related to speech fluency and cognitive alertness. These data support the notion that there is a dietary effect on GABA signaling within the cerebellum, as well as the importance of considering nutritional intervention methods as an adjunct treatment for patients chronically treated with neuroleptics. Finally, we indicate that future studies involving the analysis of individual patient's genetic profiles will further assist towards a precision medicine approach to the treatment of schizophrenia.

Prevalence and Associated Factors of Dyslipidemia Among Psychiatric Patients on Antipsychotic Treatment at Hawassa University Comprehensive Specialized Hospital

Background:

Dyslipidemia is one of the adverse metabolic outcomes associated with psychotropic medications and the nature of the mental illness itself. Therefore, this study aimed to assess magnitude of dyslipidemia and associated factors among patients with severe mental illness on antipsychotic treatments.

Methods:

A cross-sectional study was conducted among 245 patients with severe mental illness in Hawassa University Comprehensive Specialized Hospital, Sidama Regional state, Southern Ethiopia. Socio-demographic and other important data were collected using a structured questionnaire through a systematic random sampling technique. Individual dyslipidemia was characterized by the National Cholesterol Education Program Adult Treatment Panel-III (NCEP ATP-III) guideline.

Results:

Mean total cholesterol (TC) was significantly higher in males when compared to females (162.2 mg/dl vs 121 mg/dl, P = .023). While, mean LDL-cholesterol was significantly higher in females when compared to males (100.9 mg/dl vs 93.6 mg/dl, P = .028). Overall 58.4% (95% CI: 52.2-64.8) of participants had at least 1 dyslipidemia. The prevalence of TC ⩾200 mg/dl, HDL-cholesterol <40 mg/dl, triglyceride (TG) and LDL-cholesterol were 61 (24.9%), 75 (30.6%), 66 (26.9%), and 47 (19.2%), respectively. Female sex and smoking were significantly and positively associated with LDL-c dyslipidemia, the aOR (95% CI) were 2.1 (1.0-4.2) for female sex and 3.4 (1.1-10.5) for smoking. Also, Age >40 years was significantly associated with TC dyslipidemia, the aOR (95% CI) was 2.0 (1.1-3.7).

Conclusion:

More than half of psychiatric patients are at risk of developing cardiovascular and other related health problems. Therefore, periodic screening of lipid profiles during healthcare follow-up is mandatory to limit risks of cardiovascular-related comorbidities among patients with severe mental illness.

The Burden of Antipsychotic-Induced Weight Gain and Metabolic Syndrome in Children

Antipsychotic medications are critical to child and adolescent psychiatry, from the stabilization of psychotic disorders like schizophrenia, bipolar disorder, and psychotic depression to behavioral treatment of autism spectrum disorder, tic disorders, and pediatric aggression. While effective, these medications carry serious risk of adverse events-most commonly, weight gain and cardiometabolic abnormalities. Negative metabolic consequences affect up to 60% of patients and present a major obstacle to long-term treatment. Since antipsychotics are often chronically prescribed beginning in childhood, cardiometabolic risk accumulates. An increased susceptibility to antipsychotic-induced weight gain (AIWG) has been repeatedly documented in children, particularly rapid weight gain. Associated cardiometabolic abnormalities include central obesity, insulin resistance, dyslipidemia, and systemic inflammation. Lifestyle interventions and medications such as metformin have been proposed to reduce risk but remain limited in efficacy. Furthermore, antipsychotic medications touted to be weight-neutral in adults can cause substantial weight gain in children. A better understanding of the biological underpinnings of AIWG could inform targeted and potentially more fruitful treatments; however, little is known about the underlying mechanism. As yet, modest genetic studies have nominated a few risk genes that explain only a small percentage of the risk. Recent investigations have begun to explore novel potential mechanisms of AIWG, including a role for gut microbiota and microbial metabolites. This article reviews the problem of AIWG and AP metabolic side effects in pediatric populations, proposed mechanisms underlying this serious side effect, and strategies to mitigate adverse impact. We suggest future directions for research efforts that may advance the field and lead to improved clinical interventions.

Exploring Patterns of Disturbed Eating in Psychosis: A Scoping Review

Disturbed eating behaviours have been widely reported in psychotic disorders since the early 19th century. There is also evidence that antipsychotic (AP) treatment may induce binge eating or other related compulsive eating behaviours. It is therefore possible that abnormal eating patterns may contribute to the significant weight gain and other metabolic disturbances observed in patients with psychosis. In this scoping review, we aimed to explore the underlying psychopathological and neurobiological mechanisms of disrupted eating behaviours in psychosis spectrum disorders and the role of APs in this relationship. A systematic search identified 35 studies that met our eligibility criteria and were included in our qualitative synthesis. Synthesizing evidence from self-report questionnaires and food surveys, we found that patients with psychosis exhibit increased appetite and craving for fatty food, as well as increased caloric intake and snacking, which may be associated with increased disinhibition. Limited evidence from neuroimaging studies suggested that AP-naïve first episode patients exhibit similar neural processing of food to healthy controls, while chronic AP exposure may lead to decreased activity in satiety areas and increased activity in areas associated with reward anticipation. Overall, this review supports the notion that AP use can lead to disturbed eating patterns in patients, which may contribute to AP-induced weight gain. However, intrinsic illness-related effects on eating behaviors remain less well elucidated, and many confounding factors as well as variability in study designs limits interpretation of existing literature in this field and precludes firm conclusions from being made.

Treatment-related weight gain and metabolic complications in children with mental health disorders: potential role for lifestyle interventions

Over 1 million Canadian children are estimated to have a mental health disorder, which are commonly treated with medications, such as second-generation antipsychotics (SGAs). Estimates suggest that SGA prescriptions to children are increasing in Canada. Although these medications are important and lifesaving components of psychiatric treatment, they are not without side effects. For some children, SGA treatment is associated with adverse metabolic complications including rapid weight gain, dyslipidemia, elevated blood pressure, and risk for type 2 diabetes. It is not clear why these complications develop, but it is assumed that SGAs stimulate appetite and food intake, and reduce resting energy expenditure leading to weight gain and that the metabolic complications occur secondary to the weight gain. Understanding the mechanisms underlying these complications is key to being able to identify children at risk and prevent and optimize treatment. In this narrative review, we provide an overview of the literature pertaining to the weight gain and metabolic complications in children treated with SGAs, highlighting the scope of the problem and the current limited research on how diet and physical activity can be used to prevent or lessen the severity of the metabolic complications and improve the long-term health trajectories of SGA-treated children. Novelty: Children are increasingly being treated with second-generation antipsychotics for mental health disorders. Dietary and physical activity assessments are not commonly considered in clinical settings. Randomized controlled trials of lifestyle interventions are needed to determine the effectiveness of mitigating the cardiometabolic complications in second-generation antipsychotic-treated children.

Integrative Management of Metabolic Syndrome in Youth Prescribed Second-Generation Antipsychotics

Weight gain and metabolic syndrome are common side effects of second-generation antipsychotics and carry significant health consequences both in childhood and into adulthood. This review highlights evidence-based, non-pharmacologic interventions to assist in the management of these side effects. Such intervention categories include dietary, physical activity, sleep, stress management, and nutritional supplementation. Interventions with the highest quality evidence include increasing the consumption of fruits, vegetables, and whole grains, increasing physical activity, improving sleep, and fish oil supplementation. We suggest that clinicians work with patients on managing metabolic side effects in a patient-centered way, incorporating principles of motivational interviewing, to reduce the risk of metabolic syndrome.

Evaluation of subacute toxicity and herb-drug interaction potential of an herbal Arishta formulation

Background Arishta technology is an age-old heritage and uses herbal decoctions to prepare self-generated alcoholic medicines. In Ayurveda, Arishta preparations are widely used as a remedy for metabolic disorders. However, their safety and influence on herb metabolism pathways were not yet explored. Aim: To study the subacute toxicity of a polyherbal Arishta formulation (coded as DB-07) in rats and to evaluate its potential for inhibition of the drug-metabolizing enzyme (Cytochrome P450 3A4). Methodology Experimentally naive rats were treated with graded oral doses of DB-07 (10 and 20 mL/kg/day) for 28 days. During the course of the experiment, all the animals were closely observed for apparent behavioural abnormalities and mortalities. Tissue histology was performed to assess any sign of toxicity. In addition, in vitro CYP3A4 inhibition assay was performed to study the effect on drug metabolism pathways. Results Animals did not show any change in body weight, organ toxicity and food consumption throughout the dosing period of 28 days. Pathophysiological, behavioural status and locomotor activity were not altered. DB-07 did not inhibit CYP3A4 enzyme and drug metabolism pathway in-vitro. Gallic acid and quercetin were identified as phytomarker from the formulation that may be responsible for its activity related safety issue. Conclusion These results indicate that use of DB-07 may be safe with no sign of toxicity for up to 28 days in rats. Further, CYP3A4 inhibition assay indicated that DB-07 is less likely to have herb-drug interactions when concomitantly administered with CYP3A4 inhibitors or inducer.

Food craving and consumption evolution in patients starting treatment with clozapine

BACKGROUND

Antipsychotic-induced weight gain has been especially related to clozapine and olanzapine. Underlying mechanisms in relation to food preferences with an increased food craving and consumption of specific nutrients have not been extensively studied in patients with serious mental illness (SMI). We aim to describe specific food preferences (craving) and subsequent food consumption in SMI patients starting clozapine, as well as their possible relation to weight and body mass index (BMI).

METHODS

An observational prospective follow-up study (18 weeks) was conducted in a cohort of 34 SMI patients who started clozapine due to resistant-psychotic symptoms. Anthropometric measures, Food Craving Inventory (FCI), and a food consumption frequency questionnaire were evaluated at baseline, weeks 8 and 18 of treatment. Statistical analysis included generalized estimating equations models with adjustment for potential confounding factors.

RESULTS

No longitudinal changes over time were found across the different food craving scores after 18 weeks of treatment. However, adjusted models according to BMI status showed that the normal weight (NW) group presented an increased score for the "complex carbohydrates/proteins" food cravings (- 0.67; 95% CI [- 1.15, - 0.19]; P = 0.010), while baseline scores for "fast-food fats" cravings were significantly higher in the overweight/obese (OWO) group in comparison with NW patients (NW, 2.05; 95% CI [1.60, 2.49]; OWO, 2.81, 95% CI [2.37, 3.25]; P = 0.016). When considering if food craving could predict weight gain, only increments in "fast-food fats" cravings were associated (β = - 5.35 ± 1.67; 95% CI [- 8.64, - 2.06]; P = 0.001).

CONCLUSIONS

No longitudinal differences were found for any of the food craving scores evaluated; however, in the NW group, food craving for "complex carbohydrates/proteins" changed. Thus, changes in "fast-food fats" cravings predicted weight increase in this sample. Interventions targeting food preferences may help to mitigate weight gain in patients starting treatment with clozapine.

Beneficial Effects of GLP-1 Agonist in a Male With Compulsive Food-Related Behavior Associated With Autism

Individuals with autism spectrum disorder (ASD) frequently display intensely repetitive, restricted thoughts, and behaviors. These behaviors have similarities to compulsions and/or obsessions in obsessive compulsive disorder (OCD) and are primarily treated with behaviourally-based interventions and serotonin uptake inhibitors (SSRIs). Due to the lack of treatment responses in many cases, however, new treatments are being sought. Here we report beneficial effects of treatment with liraglutide, a glucagon-like peptide-1 (GLP-1) analog, on severe obsessive food craving, binge eating, weight gain, and behavioral problems in an adolescent male with infantile autism and moderate intellectual impairment. Liraglutide treatment reduced weight and unwanted behavior seemingly by preventing food-related repetitive thoughts and compulsions. Our report provides clinical evidence that GLP-1 signaling pathway may represent a novel target for treating food-related behavioral problems and aggressive behavior in ASD.

An overview of energy and metabolic regulation

The physiology and behaviors related to energy balance are monitored by the nervous and humoral systems. Because of the difficulty in treating diabetes and obesity, elucidating the energy balance mechanism and identifying critical targets for treatment are important research goals. Therefore, the purpose of this article is to describe energy regulation by the central nervous system (CNS) and peripheral humoral pathway. Homeostasis and rewarding are the basis of CNS regulation. Anorexigenic or orexigenic effects reflect the activities of the POMC/CART or NPY/AgRP neurons within the hypothalamus. Neurotransmitters have roles in food intake, and responsive brain nuclei have different functions related to food intake, glucose monitoring, reward processing. Peripheral gut- or adipose-derived hormones are the major source of peripheral humoral regulation systems. Nutrients or metabolites and gut microbiota affect metabolism via a discrete pathway. We also review the role of peripheral organs, the liver, adipose tissue, and skeletal muscle in peripheral regulation. We discuss these topics and how the body regulates metabolism.

Contribution of parasympathetic muscarinic augmentation of insulin secretion to olanzapine-induced hyperinsulinemia

Atypical antipsychotic drugs have been associated with the development of obesity and diabetes. In particular, olanzapine can induce peripheral insulin resistance and compensatory hyperinsulinemia independent of weight gain or psychiatric disease. To determine if this compensatory increase in insulin is mediated by parasympathetic muscarinic stimulation, we randomized 15 healthy subjects 2:1 to receive double-blind olanzapine or placebo for 9 days under diet- and activity-controlled inpatient conditions. Before and after 7 days of study drug administration, subjects underwent frequently sampled intravenous glucose tolerance tests with either saline or atropine infused on subsequent days to assess insulin secretion and hepatic insulin extraction in the absence or presence of muscarinic blockade. We found that olanzapine led to an increase in the acute insulin response to glucose, which was not seen with placebo, and was attenuated in the olanzapine group by atropine. Deconvolution of C-peptide data confirmed an increase in insulin secretion with olanzapine, which was blocked by atropine, with a modest reduction in hepatic insulin extraction with olanzapine. These results support the contribution of muscarinic augmentation of insulin secretion to olanzapine-induced hyperinsulinemia, and provide a mechanism for the compensatory hyperinsulinemia that normally serves to prevent deterioration of glucose tolerance under conditions of metabolic challenge.

Pathophysiology of drug induced weight and metabolic effects: findings from an RCT in healthy volunteers treated with olanzapine, iloperidone, or placebo

Second generation antipsychotics are prescribed for an increasing number of psychiatric conditions, despite variable associations with weight gain, dyslipidemia, and impaired glucose tolerance. The mechanism(s) of the apparent causal relationships between these medications and metabolic effects have been inadequately defined and are potentially confounded by genetic risk of mental illness, attendant lifestyle, and concomitant medications. Therefore, we conducted a study in which 24 healthy volunteers were randomized to olanzapine (highly weight-gain liability), iloperidone (less weight-gain liability), or placebo treatment for 28 days under double-blind conditions. We hypothesized that antipsychotics induce weight gain primarily through increased caloric intake, which causes secondary dyslipidemia and insulin resistance. Subjects were phenotyped pre- and post-treatment for body weight, adiposity by dual energy X-ray absorptiometry, energy expenditure by indirect calorimetry, food intake, oral glucose tolerance, plasma lipids, glucose, insulin, and other hormones. We found significantly increased food intake and body weight but no change in energy expenditure in olanzapine-treated subjects, with associated trends towards lipid abnormalities and insulin resistance the extent of which were presumably limited by the duration of treatment. Iloperidone treatment led to modest non-significant and placebo no weightgain, lipid increases and alterations in insulin metabolism. We conclude that second generation antipsychotic drugs, as represented by olanzapine, produce their weight and metabolic effects, predominantly, by increasing food intake which leads to weight gain that in turn induces metabolic consequences, but also through other direct effects on lipid and glucose metabolism independant of food intake and weight gain.

Antipsychotic Drugs: From Receptor-binding Profiles to Metabolic Side Effects

BACKGROUND

Antipsychotic-induced metabolic side effects are major concerns in psychopharmacology and clinical psychiatry. Their pathogenetic mechanisms are still not elucidated.

METHODS

Herein, we review the impact of neurotransmitters on metabolic regulation, providing insights into antipsychotic-induced metabolic side effects.

RESULTS

Antipsychotic drugs seem to interfere with feeding behaviors and energy balance, processes that control metabolic regulation. Reward and energy balance centers in central nervous system constitute the central level of metabolic regulation. The peripheral level consists of skeletal muscles, the liver, the pancreas, the adipose tissue and neuroendocrine connections. Neurotransmitter receptors have crucial roles in metabolic regulation and they are also targets of antipsychotic drugs. Interaction of antipsychotics with neurotransmitters could have both protective and harmful effects on metabolism.

CONCLUSION

Emerging evidence suggests that antipsychotics have different liabilities to induce obesity, diabetes and dyslipidemia. However this diversity cannot be explained merely by drugs'pharmacodynamic profiles, highlighting the need for further research.

Adipocyte cannabinoid receptor CB1 regulates energy homeostasis and alternatively activated macrophages

Dysregulated adipocyte physiology leads to imbalanced energy storage, obesity, and associated diseases, imposing a costly burden on current health care. Cannabinoid receptor type-1 (CB1) plays a crucial role in controlling energy metabolism through central and peripheral mechanisms. In this work, adipocyte-specific inducible deletion of the CB1 gene (Ati-CB1-KO) was sufficient to protect adult mice from diet-induced obesity and associated metabolic alterations and to reverse the phenotype in already obese mice. Compared with controls, Ati-CB1-KO mice showed decreased body weight, reduced total adiposity, improved insulin sensitivity, enhanced energy expenditure, and fat depot-specific cellular remodeling toward lowered energy storage capacity and browning of white adipocytes. These changes were associated with an increase in alternatively activated macrophages concomitant with enhanced sympathetic tone in adipose tissue. Remarkably, these alterations preceded the appearance of differences in body weight, highlighting the causal relation between the loss of CB1 and the triggering of metabolic reprogramming in adipose tissues. Finally, the lean phenotype of Ati-CB1-KO mice and the increase in alternatively activated macrophages in adipose tissue were also present at thermoneutral conditions. Our data provide compelling evidence for a crosstalk among adipocytes, immune cells, and the sympathetic nervous system (SNS), wherein CB1 plays a key regulatory role.

Melatonin for Reducing Weight Gain Following Administration of Atypical Antipsychotic Olanzapine for Adolescents with Bipolar Disorder: A Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVES

We aimed to evaluate melatonin effectiveness in weight gain reduction following olanzapine use for 11-17-year-old bipolar disorder patients.

EXPERIMENTAL DESIGN

Seventy-seven adolescent outpatients, subsequent to their initial diagnosis of bipolar I disorder by a psychiatrist, entered this study. After assessing inclusion and exclusion criteria, 48 patients consented to participate. Twenty-four patients were allocated to receive olanzapine, lithium carbonate, and melatonin, and 24 patients were allocated to receive olanzapine, lithium carbonate, and placebo by simple randomization. The Young Mania Rating Scale (YMRS) was performed at baseline. Before treatment and after 6 and 12 weeks of treatment, weight, height, and body mass index (BMI) were measured. Analysis of variance (ANOVA) with repeated measure and t-test were used to analyze data.

PRINCIPAL OBSERVATIONS

Nineteen patients in each group finished the study and their data were entered for analysis. Mean rise in BMI in the melatonin group compared with placebo (2.45 vs. 3.25 respectively) was marginally significant (t = 1.936; df = 36; p = 0.061). ANOVA with repeated measure also showed a marginally significant difference (F = 3.74; df = 1; p = 0.061) between groups and across time in regard to BMI. Mean body weight rise in the melatonin group compared with the placebo group (5.8 kg vs. 8.2 kg respectively) was marginally significant (t = 1.923; df = 28; p = 0.065). ANOVA with repeated measure also showed a marginally significant difference (F = 3.73; df = 1.1; p = 0.056) between groups and across time for body weight.

CONCLUSIONS

Coadministration of melatonin with olanzapine and lithium carbonate in adolescents with bipolar disorder could reduce the sharp weight gain side effect of these drugs to near significance.

Interaction Between Atypical Antipsychotics and the Gut Microbiome in a Bipolar Disease Cohort

OBJECTIVES

The atypical antipsychotic (AAP) class is often associated with metabolic disease, but the mechanistic underpinnings of this risk are not understood. Due to reports linking gut bacteria function to metabolic disease, we hypothesize that AAP treatment in adults results in gut dysbiosis potentiating metabolic criteria. This report describes recent findings linking AAP treatment with differences in gut microbiota communities in a human cohort with bipolar disorder (BD).

METHODS

In a cross-sectional design, we obtained 16S ribosomal sequences from 117 BD patients (49 AAP treated, 68 non-AAP treated). Analysis of molecular variance (AMOVA) was used to detect significant clustering of microbial communities between groups, and the inverse Simpson Diversity Index was used to calculate alpha diversity. Detection of differentially abundant operational taxonomic units (OTUs) between groups was performed using linear discriminant analysis effect size.

RESULTS

The AAP-treated cohort was significantly younger and had an increased body mass index compared with non-AAP-treated patients. Groups did not differ in other psychotropic medication use with the exception of higher use of benzodiazepines in the AAP cohort. We detected significant separation between microbiota communities of AAP-treated and nontreated patients (AMOVA; p=0.04). AAP-treated females showed significant decreased species diversity when compared with non-AAP-treated females (p=0.015). Males showed no significant diversity between treatment groups (p=0.8). Differentially abundant OTUs between treatment groups were OTU1, OTU25, and OTU32 that classified to Lachnospiraceae, Akkermansia, and Sutterella, respectively.

CONCLUSIONS

These data suggest that AAP treatment is associated with specific representation of gut bacterial families in AAP-treated patients. In addition, AAP treatment is associated with decreased species richness in female AAP-treated patients.

Acute and subchronic toxicity studies of methanol extract of Polygonum minus leaves in Sprague Dawley rats

Medicinal plant preparations may contain high levels of toxic chemical constituents to potentially cause serious harm to animals and/or humans. Thus, toxicity studies are important to assess the toxic effects of plant derived products. Polygonum minus is used traditionally for different ailments in Southeast Asia. This study was conducted to establish the acute and subchronic toxicity profile of the methanol extract of P. minus leaves. The acute toxicity study showed that the methanol extract of P. minus is safe even at the highest dose tested of 2000 mg/kg in female Sprague Dawley rats. There were no behavioural or physiological changes and gross pathological abnormalities observed. The subchronic toxicity study of methanol extract of P. minus at 250, 500, 1000 and 2000 mg/kg were conducted in both sexes of Sprague Dawley rats. There were no changes observed in the extract treated animal's body weight, food and water intake, motor coordination, behaviour and mental alertness. The values of haematological and biochemical parameters were not different between the treated and control animals. The relative organ weights of extract-treated animals did not differ with that of control animals. Based on the present findings, the methanol extract of P. minus leaves could be considered safe up to the dose of 2000 mg/kg.

Can We Selectively Reduce Appetite for Energy-Dense Foods? An Overview of Pharmacological Strategies for Modification of Food Preference Behavior

Excessive intake of food, especially palatable and energy-dense carbohydrates and fats, is largely responsible for the growing incidence of obesity worldwide. Although there are a number of candidate antiobesity drugs, only a few of them have been proven able to inhibit appetite for palatable foods without the concurrent reduction in regular food consumption. In this review, we discuss the interrelationships between homeostatic and hedonic food intake control mechanisms in promoting overeating with palatable foods and assess the potential usefulness of systemically administered pharmaceuticals that impinge on the endogenous cannabinoid, opioid, aminergic, cholinergic, and peptidergic systems in the modification of food preference behavior. Also, certain dietary supplements with the potency to reduce specifically palatable food intake are presented. Based on human and animal studies, we indicate the most promising therapies and agents that influence the effectiveness of appetite-modifying drugs. It should be stressed, however, that most of the data included in our review come from preclinical studies; therefore, further investigations aimed at confirming the effectiveness and safety of the aforementioned medications in the treatment of obese humans are necessary.

Significant weight loss following clozapine use, how is it possible? A case report and review of published cases and literature relevant to the subject

It has been repeatedly shown that clozapine is more efficacious than other antipsychotics in the management of treatment-resistant schizophrenia. However, clozapine is associated with a number of side effects including weight gain. Antipsychotic-induced weight gain has been linked with a number of untoward events including psychological factors such as stigma and low self-esteem, and physical factors such as metabolic syndromes and untimely death. The mechanism underlying antipsychotic (including clozapine)-induced weight gain is not clearly understood, although it is said to involve several brain areas, several neurotransmitters, neuropeptides and genetic factors. To some individuals however, clozapine use is associated with significant weight loss (13.5-50% of body weight). The observed weight loss in these groups of patients has not been attributed to any underlying diagnosable physical disorders. There have been a handful cases published with this phenomenon, which seems to be contrary to what is expected when clozapine is prescribed. From the currently published cases three groups emerge - those who lost weight simply by taking clozapine, those who lost weight due to improved mental state, engaging in diet and increased exercise, and those for whom weight loss was a sign of a poor response to clozapine. A case of JX who has a diagnosis of schizoaffective disorder is presented. JX lost over 26% of her body weight when she was prescribed clozapine. A detailed review of other published cases is undertaken. The underlying mechanisms involving weight loss are discussed and the implications to clinicians are highlighted. Coordinated studies to examine these groups of patients may provide some insight, not only in the mechanism of clozapine-induced weight loss, but also in the better management of patients with treatment-resistant schizophrenia involving clozapine use.

Olanzapine Is Faster than Haloperidol in Inducing Metabolic Abnormalities in Schizophrenic and Bipolar Patients

The effects of olanzapine and haloperidol on metabolic parameters in bipolar patients have been evaluated much less comprehensively than in schizophrenic patients. Therefore, in this study, medical records of 343 schizophrenic and bipolar patients treated with haloperidol or olanzapine for 1 year were retrospectively reviewed and metabolic outcomes were evaluated. After 12 months of follow-up, 25.9% of patients showed ≥3 metabolic abnormalities with a point prevalence of 27.2% in the bipolar and 24.9% in the schizophrenic group: 22.0% of the schizophrenic patients treated with haloperidol and 29.8% of those treated with olanzapine achieved ≥3 metabolic alterations; in bipolar patients, these percentages were 15.8% of those treated with haloperidol and 37.8% of those treated with olanzapine (p < 0.0001). Significant changes were reported over time in fasting glucose, triglycerides and cholesterol blood levels, systolic and diastolic blood pressure, body weight, and BMI. Overall, a significant number of schizophrenic and bipolar patients treated with olanzapine showed ≥3 metabolic alterations in the first month of treatment when compared to those treated with haloperidol. Moreover, the number of olanzapine-treated patients developing metabolic changes in the first month was significantly higher in both diagnostic groups when compared to those who reached metabolic abnormal values in the subsequent 11 months. These data suggest that both antipsychotics could increase the metabolic risk in schizophrenic and bipolar patients with a higher prevalence in olanzapine-treated patients. On the other hand, olanzapine-treated patients seem to achieve metabolic abnormalities faster than haloperidol-treated subjects in both diagnostic groups.

Negative Correlation between Serum S100B and Leptin Levels in Schizophrenic Patients During Treatment with Clozapine and Risperidone: Preliminary Evidence

Recently, extensive efforts have been made to understand the rate of energy expenditure and the weight gain associated with atypical antipsychotic treatment, including identification of markers of obesity risk. In recent years, leptin, an adipocyte hormone, has gained significant interest in psychiatric disorders. S100B has been considered as a surrogate marker for astrocyte-specific damage in neurologic disorders. Also, S100B has been detected in adipose with concentration as high as nervous tissue as a second release source. In this study we evaluated the relationship between S100B and leptin in schizophrenic patients under treatment with clozapine and risperidone.This study included 19 patients meeting the DSM-IV-TR criteria for schizophrenia, having body mass index (BMI) of 16- 25 kg/m(2) and suffering schizophrenia for more than 3 years and from this study. Twenty five healthy controls were group matched for age and gender whose BMI was 16-25 kg/m(2). Serum S100B and leptin levels and positive and negative symptom scale (PANSS) were assessed at admission and after six weeks. During the study, S100B showed a strong and negative correlation with leptin (r = -0.5, P = 0.01). Also, there were negative correlation between serum S100B level and PANSS negative subscale after 6 weeks of treatment (r = -0.048, P = 0.8). Positive correlation between leptin level and PANSS suggested a potential role for leptin which can mediate the link between antipsychotic induced weight gain and therapeutic response in schizophrenia.

Proteome effects of antipsychotic drugs: Learning from preclinical models

Proteome-wide expression analyses are performed in the brain of schizophrenia patients to understand the biological basis of the disease and discover molecular paths for new clinical interventions. A major issue with postmortem analysis is the lack of tools to discern molecular modulation related to the disease from dysregulation due to medications. We review available proteome-wide analysis of antipsychotic treatment in rodents, highlighting shared dysregulated pathways that may contribute to an extended view of molecular processes underlying their pharmacological activity. Fourteen proteomic studies conducted with typical and atypical antipsychotic treatments were examined; hypothesis-based approaches are also briefly discussed. Treatment with antipsychotics mainly affects proteins belonging to metabolic pathways involved in energy generation, both in glycolytic and oxidative phosphorylation pathways, suggesting antipsychotics-induced impairments in metabolism. Nevertheless, schizophrenic patients show impaired glucose metabolism and mitochondrial dysfunctions independent of therapy. Other antipsychotics-induced changes shared by different studies implicate cytoskeletal and synaptic function proteins. The mechanism can be related to the reorganization of dendritic spines resulting from neural plasticity events induced by treatments affecting neurotransmitter circuitry. However, metabolic and plasticity pathways activated by antipsychotics can also play an authentic role in the etiopathological basis of schizophrenia.

Metabolic syndrome and obesity among users of second generation antipsychotics: A global challenge for modern psychopharmacology

Second generation antipsychotics (SGAs), such as clozapine, olanzapine, risperidone and quetiapine, are among the most effective therapies to stabilize symptoms schizophrenia (SZ) spectrum disorders. In fact, clozapine, olanzapine and risperidone have improved the quality of life of billions SZ patients worldwide. Based on the broad spectrum of efficacy and low risk of extrapyramidal symptoms displayed by SGAs, some regulatory agencies approved the use of SGAs in non-schizophrenic adults, children and adolescents suffering from a range of neuropsychiatric disorders. However, increasing number of reports have shown that SGAs are strongly associated with accelerated weight gain, insulin resistance, diabetes, dyslipidemia, and increased cardiovascular risk. These metabolic alterations can develop in as short as six months after the initiation of pharmacotherapy, which is now a controversial fact in public disclosure. Although the percentage of schizophrenic patients, the main target group of SGAs, is estimated in only 1% of the population, during the past ten years there was an exponential increase in the number of SGAs users, including millions of non-SZ patients. The scientific bases of SGAs metabolic side effects are not yet elucidated, but the evidence shows that the activation of transcriptional factor SRBP1c, the D1/D2 dopamine, GABA2 and 5HT neurotransmitions are implicated in the SGAs cardiovascular toxicity. Polypharmacological interventions are either non- or modestly effective in maintaining low cardiovascular risk in SGAs users. In this review we critically discuss the clinical and molecular evidence on metabolic alterations induced by SGAs, the evidence on the efficacy of classical antidiabetic drugs and the emerging concept of antidiabetic polyphenols as potential coadjutants in SGA-induced metabolic disorders.

The histaminergic system as a target for the prevention of obesity and metabolic syndrome

The control of food intake and body weight is very complex. Key factors driving eating behavior are hunger and satiety that are controlled by an interplay of several central and peripheral neuroendocrine systems, environmental factors, the behavioral state and circadian rhythm, which all concur to alter homeostatic aspects of appetite and energy expenditure. Brain histamine plays a fundamental role in eating behavior as it induces loss of appetite and has long been considered a satiety signal that is released during food intake (Sakata et al., 1997). Animal studies have shown that brain histamine is released during the appetitive phase to provide a high level of arousal preparatory to feeding, but also mediates satiety. Furthermore, histamine regulates peripheral mechanisms such as glucose uptake and insulin function. Preclinical research indicates that activation of H1 and H3 receptors is crucial for the regulation of the diurnal rhythm of food consumption; furthermore, these receptors have been specifically recognized as mediators of energy intake and expenditure. Despite encouraging preclinical data, though, no brain penetrating H1 receptor agonists have been identified that would have anti-obesity effects. The potential role of the H3 receptor as a target of anti-obesity therapeutics was explored in clinical trials that did not meet up to the expectations or were interrupted (clinicaltrials.gov). Nonetheless, interesting results are emerging from clinical trials that evaluated the attenuating effect of betahistine (an H1 agonist/H3 antagonist) on metabolic side effects associated with chronic antipsychotics treatment. Aim of this review is to summarize recent results that suggest the clinical relevance of the histaminergic system for the treatment of feeding disorders and provide an up-to-date summary of preclinical research. This article is part of the Special Issue entitled 'Histamine Receptors'.

Psychometric properties of the self-report version of the Quick Inventory of Depressive Symptoms (QIDS-SR₁₆) questionnaire in patients with schizophrenia

BACKGROUND

Self-report instruments for the assessment of depressive symptoms in patients with psychotic disorders are scarce. The Quick Inventory of Depressive Symptoms (QIDS-SR16) may be a useful self-report instrument, but has received little attention in this field. This paper aimed to test the psychometric properties of the QIDS-SR16 questionnaire in patients with a psychotic disorder.

METHODS

Patients diagnosed with a psychotic disorder from health care institutions in The Netherlands were included in the study. Depressive symptoms were assessed with the QIDS-SR16 and the Calgary Depression Scale for Schizophrenia (CDSS). Psychotic symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS) and extrapyramidal symptoms (EPS) with three EPS rating scales. Spearman's correlation coefficients were used to compare the total score of the QIDS-SR16 with the total scores of the CDSS, PANSS-subscales and EPS rating scales.

RESULTS

In a sample of 621 patients with psychotic disorders, the QIDS-SR16 showed good internal consistency (α = 0.87). The QIDS-SR16 correlated moderately with the CDSS (r = 0.44) and the PANSS subscale for emotional distress (r = 0.47). The QIDS-SR16 showed weak correlation with the PANSS subscale for negative symptoms (r = 0.28) and minimal correlation with EPS rating scales (r = 0.09-0.16).

CONCLUSIONS

The QIDS-SR16 may reliably assess depressive symptoms in patients with psychotic disorders, but its concurrent validity with the CDSS was rather poor in this population. We would recommend developing a new self-report questionnaire for the assessment of depressive symptoms in patients with psychotic disorders.

Metabolomic profiling of schizophrenia patients at risk for metabolic syndrome

Second-generation antipsychotics (SGAs) are commonly used to treat schizophrenia. However, SGAs cause metabolic disturbances that can manifest as metabolic syndrome (MetS) in a subset of patients. The causes for these metabolic disturbances remain unclear. We performed a comprehensive metabolomic profiling of 60 schizophrenia patients undergoing treatment with SGAs that puts them at high (clozapine, olanzapine), medium (quetiapine, risperidone), or low (ziprasidone, aripiprazole) risk for developing MetS, compared to a cohort of 20 healthy controls. Multiplex immunoassays were used to measure 13 metabolic hormones and adipokines in plasma. Mass spectrometry was used to determine levels of lipids and polar metabolites in 29 patients and 10 controls. We found that levels of insulin and tumor necrosis factor alpha (TNF-α) were significantly higher (p < 0.005) in patients at medium and high risk for MetS, compared to controls. These molecules are known to be increased in individuals with high body fat content and obesity. On the other hand, adiponectin, a molecule responsible for control of food intake and body weight, was significantly decreased in patients at medium and high risk for MetS (p < 0.005). Further, levels of dyacylglycerides (DG), tryacylglycerides (TG) and cholestenone were increased, whereas α-Ketoglutarate and malate, important mediators of the tricarboxylic acid (TCA) cycle, were significantly decreased in patients compared to controls. Our studies suggest that high- and medium-risk SGAs are associated with disruption of energy metabolism pathways. These findings may shed light on the molecular underpinnings of antipsychotic-induced MetS and aid in design of novel therapeutic approaches to reduce the side effects associated with these drugs.

Circuits controlling energy balance and mood: inherently intertwined or just complicated intersections?

Recent reports of adverse psychiatric events from seemingly different types of weight loss therapies highlight a previously underestimated overlap between CNS circuits that control energy balance and those that regulate mood. In this Perspective, we discuss a few potential brain sites where the homeostatic and the hedonic pathways may intersect and suggest that a better understanding of both pathways is necessary for the development of more effective and safer antiobesity therapies.

Recent evidence and potential mechanisms underlying weight gain and insulin resistance due to atypical antipsychotics

OBJECTIVE

Atypical antipsychotics (AAPs) promote obesity and insulin resistance. In this regard, the main objective of this study was to present potential mechanisms and evidence concerning side effects of atypical antipsychotics in humans and rodents.

METHOD

A systematic review of the literature was performed using the MEDLINE database. We checked the references of selected articles, review articles, and books on the subject.

RESULTS

This review provides consistent results concerning the side effects of olanzapine (OL) and clozapine (CLZ), whereas we found conflicting results related to other AAPs. Most studies involving humans describe the effects on body weight, adiposity, lipid profile, and blood glucose levels. However, it seems difficult to identify an animal model replicating the wide range of changes observed in humans. Animal lineage, route of administration, dose, and duration of treatment should be carefully chosen for the replication of the findings in humans.

CONCLUSIONS

Patients undergoing treatment with AAPs are at higher risk of developing adverse metabolic changes. This increased risk must be taken into account when making decisions about treatment. The influence of AAPs on multiple systems is certainly the cause of such effects. Specifically, muscarinic and histaminergic pathways seem to play important roles.

Antipsychotic-induced insulin resistance and postprandial hormonal dysregulation independent of weight gain or psychiatric disease

Atypical antipsychotic (AAP) medications that have revolutionized the treatment of mental illness have become stigmatized by metabolic side effects, including obesity and diabetes. It remains controversial whether the defects are treatment induced or disease related. Although the mechanisms underlying these metabolic defects are not understood, it is assumed that the initiating pathophysiology is weight gain, secondary to centrally mediated increases in appetite. To determine if the AAPs have detrimental metabolic effects independent of weight gain or psychiatric disease, we administered olanzapine, aripiprazole, or placebo for 9 days to healthy subjects (n = 10, each group) under controlled in-patient conditions while maintaining activity levels. Prior to and after the interventions, we conducted a meal challenge and a euglycemic-hyperinsulinemic clamp to evaluate insulin sensitivity and glucose disposal. We found that olanzapine, an AAP highly associated with weight gain, causes significant elevations in postprandial insulin, glucagon-like peptide 1 (GLP-1), and glucagon coincident with insulin resistance compared with placebo. Aripiprazole, an AAP considered metabolically sparing, induces insulin resistance but has no effect on postprandial hormones. Importantly, the metabolic changes occur in the absence of weight gain, increases in food intake and hunger, or psychiatric disease, suggesting that AAPs exert direct effects on tissues independent of mechanisms regulating eating behavior.

Association of a functional polymorphism in neuropeptide Y with antipsychotic-induced weight gain in schizophrenia patients

Significant body weight gain (BWG) is a serious adverse effect of a number of antipsychotic drugs. Previous studies have demonstrated an influence of clozapine, but not haloperidol, on neuropeptide Y (NPY) expression in the hypothalamus. Because NPY is a potent orexigenic peptide stimulating food intake, and genetic variation of the gene has been shown to influence development of obesity, we investigated the impact of NPY polymorphisms on antipsychotic-induced BWG.We analyzed 5 polymorphisms in the NPY gene (rs10551063, rs16147, rs5573, rs5574, and rs16475) in schizophrenia subjects (n = 226), treated mostly with clozapine and olanzapine for up to 14 weeks. Association was tested using analysis of covariance with change (%) from baseline weight as the dependent variable and duration of treatment and baseline body weight as covariates.In patients of European ancestry who received either clozapine or olanzapine, significant genotypic and allelic association of rs16147 with weight change was observed (P(corrected) = 0.012 and 0.018, respectively). Carriers of the C allele gained significantly more weight compared with individuals with TT genotype (CC + CT vs TT; 5.82% ± 5.6% vs 2.25% ± 4.8%; P= 0.001). Similarly, 2 other polymorphisms (rs5573 and rs5574) were also significantly associated with weight change (P(corrected) = 0.018 and 0.03). In addition, we observed a significant gene-gene interaction between the rs16147 in NPY and rs806378 in cannabinoid receptor 1 (P(corrected) = 0.011).Our observation of association of NPY polymorphisms gives further evidence for a genetic influence on antipsychotic-induced BWG and suggests a role of NPY gene in influencing this complex adverse effect.

Behavioral interventions for antipsychotic induced appetite changes

Weight gain remains a well recognized yet difficult to treat adverse effect of many anti-psychotic drugs including agents of the first and second generation. The weight gain liabilities of antipsychotic drugs are partly associated with their ability to increase appetite. Most behavioral interventions for weight control remain of limited efficacy, possibly because they do not specifically target the neuroendocrine factors regulating appetite. Identifying new weight management interventions directly acting on the biochemical and neuroendocrine mechanisms of anti-psychotic induced weight gain may help to improve the efficacy of behavioral weight management programs. Such potentially specific strategies include (1) using diets which do not increase appetite despite calorie restriction; (2) countering thirst as an anticholinergic side-effect; (3) discouraging cannabis use and (4) adding metformin to a behavioral intervention. In view of our currently rather limited treatment repertoire it seems timely systematically to explore such novel options.

The vagus nerve and the inflammatory reflex--linking immunity and metabolism

The vagus nerve has an important role in regulation of metabolic homeostasis, and efferent vagus nerve-mediated cholinergic signalling controls immune function and proinflammatory responses via the inflammatory reflex. Dysregulation of metabolism and immune function in obesity are associated with chronic inflammation, a critical step in the pathogenesis of insulin resistance and type 2 diabetes mellitus. Cholinergic mechanisms within the inflammatory reflex have, in the past 2 years, been implicated in attenuating obesity-related inflammation and metabolic complications. This knowledge has led to the exploration of novel therapeutic approaches in the treatment of obesity-related disorders.

Animal models of eating disorders

Feeding is a fundamental process for basic survival and is influenced by genetics and environmental stressors. Recent advances in our understanding of behavioral genetics have provided a profound insight on several components regulating eating patterns. However, our understanding of eating disorders, such as anorexia nervosa, bulimia nervosa, and binge eating, is still poor. The animal model is an essential tool in the investigation of eating behaviors and their pathological forms, yet development of an appropriate animal model for eating disorders still remains challenging due to our limited knowledge and some of the more ambiguous clinical diagnostic measures. Therefore, this review will serve to focus on the basic clinical features of eating disorders and the current advances in animal models of eating disorders.