A prospective study of serum ghrelin levels in patients treated with clozapine

Differential expression of the ghrelin-related mRNAs GHS-R1a, GHS-R1b, and MBOAT4 in Japanese patients with schizophrenia

OBJECTIVES

Ghrelin regulates appetite and also plays important roles in cognition and may be involved in vulnerability to SCZ.

METHODS

In this study, we measured mRNA expression of the ghrelin-related molecules, growth hormone secretagogue receptor 1a (GHS-R1a) and 1b (GHS-R1b), and the ghrelin activator, membrane bound O-acyltransferase 4 (MBOAT4). Peripheral leukocytes from Japanese patients with SCZ (n = 49; 23 males, 26 females; age = 61.8 ± 13.3 years) and controls (n = 50; 25 males, 25 females; age = 62.0 ± 14.3 years) were recruited according to their clinical information. We also studied the DNA methylation rates of these genes in DNA from leukocytes.

RESULTS

The mRNA expression of GHS-R1a was significantly decreased in SCZ (SCZ vs. control: 0.35 ± 0.081 vs. 1.00 ± 0.059, respectively, p = 0.007), but expression levels of GHS-R1b and MBOAT4 were significantly increased in SCZ (SCZ vs. control: 2.02 ± 0.91 vs. 1.00 ± 0.32, p = 0.023, 1.37 ± 0.21 vs. 1.00 ± 0.11, respectively, p = 0.014). No differences in methylation rates for any genes were found.

CONCLUSION

We conclude that opposite expression of GHS-R1a and GHS-R1b, and elevated MBOAT4 mRNA expression may reflect the mechanisms of SCZ.

The association of serum nesfatin-1 and ghrelin levels with metabolic syndrome in patients with schizophrenia

Nesfatin-1 and ghrelin are two hormones which has opposite effects and play role in food intake. This study was planned on the idea that both metabolic syndrome and psychiatric disorders are associated with nesfatin-1 and ghrelin. In this study, it was aimed to investigate the levels of ghrelin and nesfatin-1 in patients with schizophrenia, by taking confounding factor as the metabolic syndrome (MS). 55 patients with schizophrenia and 33 healthy controls were included in the study.11 out of the 55 patients (%20) has MS. Serum ghrelin and nesfatin-1 levels of schizophrenia patients with MS have been compared with both healthy controls and schizophrenia patients without MS. Patients with schizophrenia had significantly higher serum nesfatin-1 levels compared to healthy controls. But serum ghrelin levels was not different in both groups. Serum nesfatin-1 concentrations were significantly higher in the schizophrenia patients with MS (10.51-350.8pg/ml) with respect to the healthy control group (4.86-68.91pg/ml). There was no significant statistical difference between the three groups in terms of ghrelin levels. Our findings suggests that, MS presence also contributed to significantly high levels of nesfatin-1 level. Nesfatin-1 may have a part in a novel studies regarding the treatment of schizophrenia and its metabolic effects.

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

OBJECTIVE

Antipsychotics (APs) are associated with metabolic syndrome, with increases in leptin proposed as an underlying mechanism of AP-induced weight gain. Currently available meta-analyses on this topic have limited their populations of interest to those diagnosed with schizophrenia. The purpose of this meta-analysis is to explore the relationship between leptin levels and AP use across multiple psychiatric diagnoses, and also in healthy controls.

METHOD

Systematic electronic searches were conducted using PubMed and OVID: Medline. Longitudinal studies were included if showing leptin levels before and after AP use. We included participants with any psychiatric disorders and mentally healthy participants, if exposed to AP use. The differences in leptin levels were evaluated using Hedges' g with a random effects model.

RESULTS

Forty-two studies were found (36 schizophrenia, 2 bipolar disorder, 1 anorexia nervosa, and 3 healthy controls), encompassing 66 study arms and 1,156 participants. The meta-analysis showed that regardless of diagnoses, leptin levels increase with AP use (Hedges' g = 0.811, p ≤ .001).

CONCLUSION

Leptin increases induced by APs are present across all diagnoses. More comprehensive research is needed to understand the relationship between AP use and leptin levels across multiple diagnoses.

Differential effects of olanzapine and clozapine on plasma levels of adipocytokines and total ghrelin

Second-generation antipsychotics (SGAs) have been associated with an increased liability for weight gain and metabolic side effects. Among SGAs, clozapine and olanzapine had great liability to induce weight gain and metabolic adverse reactions. Leptin, adiponectin, and total ghrelin play important roles in energy homeostasis and are suggested to be biomarkers of metabolic disturbances. The purpose of the present study was to investigate the differential effects of antipsychotics (olanzapine and clozapine) on the levels of adipocytokines (leptin and adiponectin) and total ghrelin. Three hundred and thirty-three patients with schizophrenia under clozapine or olanzapine monotherapy were recruited. Control participants were recruited from a healthy community population based on a health investigation (N=119). Fasting blood samples for glucose, cholesterol, triglycerides, leptin, adiponectin, and total ghrelin were analyzed. There were significant differences in the levels of cholesterol, triglycerides, and glucose between these three groups. Post hoc comparisons showed that the olanzapine group had the highest levels of cholesterol and triglycerides. The levels of leptin, adiponectin, and total ghrelin were also significantly different between the three groups after controlling age and body mass index (BMI). Post hoc comparisons showed that the olanzapine group had the lowest levels of adiponectin and total ghrelin. The present study found that the uses of olanzapine and clozapine were associated with changes in adipocytokines and total ghrelin, even after adjusting potential confounding factors. Olanzapine had greater influences on adiponectin and total ghrelin than clozapine. The changes in adipocytokines and total ghrelin were a direct effect of antipsychotics on hormonal pathways of energy homeostasis, rather than the result of weight gain.

Ghrelin in psychiatric disorders - A review

Ghrelin is a 28-amino-acid peptide hormone, first described in 1999 and broadly expressed in the organism. As the only known orexigenic hormone secreted in the periphery, it increases hunger and appetite, promoting food intake. Ghrelin has also been shown to be involved in various physiological processes being regulated in the central nervous system such as sleep, mood, memory and reward. Accordingly, it has been implicated in a series of psychiatric disorders, making it subject of increasing investigation, with knowledge rapidly accumulating. This review aims at providing a concise yet comprehensive overview of the role of ghrelin in psychiatric disorders. Ghrelin was consistently shown to exert neuroprotective and memory-enhancing effects and alleviated psychopathology in animal models of dementia. Few human studies show a disruption of the ghrelin system in dementia. It was also shown to play a crucial role in the pathophysiology of addictive disorders, promoting drug reward, enhancing drug seeking behavior and increasing craving in both animals and humans. Ghrelin's exact role in depression and anxiety is still being debated, as it was shown to both promote and alleviate depressive and anxiety-behavior in animal studies, with an overweight of evidence suggesting antidepressant effects. Not surprisingly, the ghrelin system is also implicated in eating disorders, however its exact role remains to be elucidated. Its widespread involvement has made the ghrelin system a promising target for future therapies, with encouraging findings in recent literature.

The role of ghrelin signalling in second-generation antipsychotic-induced weight gain

Based on clinical and animal studies, this review suggests a tri-phasic effect of second-generation antipsychotics (SGAs) on circulating ghrelin levels: an initial increase exerted by the acute effect of SGAs; followed by a secondary decrease possibly due to the negative feedback from the SGA-induced body weight gain or hyperphagia; and a final re-increase to reach the new equilibrium. Moreover, the results can also vary depending on individual SGAs, other hormonal states, dietary choices, and other confounding factors including medical history, co-treatments, age, gender, and ghrelin measurement techniques. Interestingly, rats treated with olanzapine, an SGA with high weight gain liabilities, are associated with increased hypothalamic ghrelin receptor (GHS-R1a) levels. In addition, expressions of downstream ghrelin signalling parameters at the hypothalamus, including neuropeptide Y (NPY)/agouti-related peptide (AgRP) and proopiomelanocortin (POMC) are also altered under SGA treatments. Thus, understanding the role of ghrelin signalling in antipsychotic drug-induced weight gain should offer potential novel pharmacological targets for tackling the obesity side-effect of SGAs and its associated metabolic syndrome.

The role of leptin in antipsychotic-induced weight gain: genetic and non-genetic factors

Schizophrenia is a chronic and disabling mental illness affecting millions of people worldwide. A greater proportion of people with schizophrenia tends to be overweight. Antipsychotic medications have been considered the primary risk factor for obesity in schizophrenia, although the mechanisms by which they increase weight and produce metabolic disturbances are unclear. Several lines of research indicate that leptin could be a good candidate involved in pathways linking antipsychotic treatment and weight gain. Leptin is a circulating hormone released by adipocytes in response to increased fat deposition to regulate body weight, acting through receptors in the hypothalamus. In this work, we reviewed preclinical, clinical, and genetic data in order to infer the potential role played by leptin in antipsychotic-induced weight gain considering two main hypotheses: (1) leptin is an epiphenomenon of weight gain; (2) leptin is a consequence of antipsychotic-induced "leptin-resistance status," causing weight gain.

Atypical antipsychotic-induced weight gain: insights into mechanisms of action

Prescriptions for second-generation antipsychotics (SGAs) have surpassed those for first-generation agents in the treatment of schizophrenia and bipolar disorder. While SGAs have the benefit of a much reduced risk of causing movement disorders, they have been associated with weight gain and metabolic effects. These adverse reactions are not uncommon, and threaten to have a significant impact on the patient's health over the long-term treatment that the patient requires. Currently, the aetiology of these effects is not known. This article reviews the data exploring the weight gain phenomenon. The literature was reviewed from searches of PubMed and the references of major articles in the field. The SGAs present a heterogeneous risk for weight gain. In addition, different individuals receiving the same drug can exhibit substantially different weight changes. This pattern suggests that a group of factors are associated with the weight gain phenomenon rather than a single mechanism. Coupled with the genetic profile that the patient brings to the treatment, the risk for SGA-induced weight gain will be different for different drugs and different individuals. Targets for exploration of the weight gain phenomenon include receptor interactions involving serotonin, histamine, dopamine, adrenergic, cannabinoid and muscarinic receptors. The association of SGA-induced weight gain and the role of orexigenic and anorexigenic peptides are reviewed. Also, a brief discussion of genetic factors associated with SGA-induced weight gain is presented, including that of the serotonin 5-HT(2C) receptor gene (HTR2C) and the cannabinoid 1 receptor gene (CNR1). The most promising data associated with SGA-induced weight gain include investigations of the histamine H(1), 5-HT(2A), 5-HT(2C), muscarinic M(3) and adrenergic receptors. In addition, work in the genetic area promises to result in a better understanding of the variation in risk associated with different individuals.

The TNF-alpha system: functional aspects in depression, narcolepsy and psychopharmacology

Changes of the tumor necrosis factor-alpha (TNF-α) system have been shown to be involved in the development of psychiatric disorders and are additionally associated with changes in body weight as well as endocrine and metabolic changes in psychiatric patients.

TNF-α might, for example, contribute to the pathogenesis of depression by an activation of the hypothalamo-pituitary-adrenocortical (HPA) axis, an activation of neuronal serotonin transporters and the stimulation of the indoleamine 2,3-dioxygenase which leads to tryptophan depletion. On the other hand, during an acute depressive episode, an elevated HPA axis activity may suppress TNF-α system activity, while after remission, when HPA axis activity has normalized the suppression of the TNF-α system has been shown not to be apparent any more.

In narcoleptic patients, soluble TNF receptor (sTNF-R) p75 plasma levels have been shown to be elevated, suggesting a functional role of the TNF-α system in the development of this disorder.

Additionally, psychotropic drugs influence the TNF-α system as well as the secretion and the effect of hormones which counteract or interact with the TNF-α system such as the intestinal hormone ghrelin. However, only preliminary studies with restricted sample sizes exist on these issues, and many open questions remain.

Plasma orexin A, ghrelin, cholecystokinin, visfatin, leptin and agouti-related protein levels during 6-week olanzapine treatment in first-episode male patients with psychosis

The objective of the study was to investigate the change of body mass index (BMI), waist circumference, lipid profile, leptin, ghrelin, orexin, visfatin, agouti-related protein, and cholecystokinin levels during 6 weeks of olanzapine treatment in newly diagnosed first-episode drug naive, young adult, nonobese male patients with psychosis. Twenty male participants who were all first-episode drug naive psychotic patients without prominent affective signs and symptoms and 22 healthy male controls of similar age were included. BMI, waist circumference, fasting glucose, and lipid profiles were measured, and Positive and Negative Syndrome Scale and Brief Psychiatric Rating Scale scores were obtained at baseline, during the second and sixth week of treatment, and the aforementioned neuropeptide levels were measured at baseline and during the sixth week of treatment. Treatment was associated with significant increases in BMI, waist circumference, serum triglyceride, and low-density lipoprotein levels. BMI levels increased more than 7% in over 75% of the patients. Leptin increased, and ghrelin and orexin decreased significantly with olanzapine treatment, whereas cholecystokinin, visfatin, and agouti-related protein levels did not change significantly. In conclusion, consistent with previous studies, we found increased BMI, leptin and lipids during olanzapine treatment. Association of neuropeptide level changes with symptom improvement might be mediated by the dopaminergic and serotonergic systems.

Short-term treatment with olanzapine does not modulate gut hormone secretion: olanzapine disintegrating versus standard tablets

BACKGROUND

Treatment with olanzapine (atypical antipsychotic drug) is frequently associated with various metabolic anomalies, including obesity, dyslipidemia, and diabetes mellitus. Recent data suggest that olanzapine orally disintegrating tablets (ODT), which dissolve instantaneously in the mouth, might cause less weight gain than olanzapine standard oral tablets (OST).

DESIGN AND METHODS

Ten healthy men received olanzapine ODT (10 mg o.d., 8 days), olanzapine OST (10 mg o.d., 8 days), or no intervention in a randomized crossover design. At breakfast and dinner, blood samples were taken for measurement of pancreatic polypeptide, peptide YY, glucagon-like peptide-1, total glucagon, total ghrelin, and cholecystokinin (CCK) concentrations.

RESULTS

With the exception of pre- and postprandial concentration of ghrelin at dinner and preprandial CCK concentrations at breakfast, which were all slightly increased (respectively P=0.048, P=0.034 and P=0.042), olanzapine did not affect gut hormone concentrations. Thus, olanzapine ODT and OST had similar effects on gut hormone secretion.

CONCLUSION

Short-term treatment with olanzapine does not have major impact on the plasma concentration of gut hormones we measured in healthy men. Moreover, despite pharmacological difference, gut hormone concentrations are similar during treatment with olanzapine ODT and OST. The capacity of olanzapine to induce weight gain and diabetes is unlikely to be caused by modulation of the secretion of gut hormones measured here. We cannot exclude the possibility that olanzapine's impact on other gut hormones, to impair insulin sensitivity and stimulate weight gain, exists.

Reproductive and metabolic abnormalities associated with bipolar disorder and its treatment

Women with mood disorders, especially bipolar disorder (BD), have been shown to have high rates of reproductive and metabolic dysfunction. The available data on the functional, anatomic, and clinical neuroendocrine abnormalities in women with BD suggest a two-tiered relationship with mood pathology. First, many of the medications commonly used in the treatment of BD can have deleterious effects on blood levels of reproductive hormones and consequently on the hypothalamic-pituitary-gonadal (HPG) axis and reproductive function. Studies that have specifically addressed the association between psychotropic medications and menstrual abnormalities, polycystic ovary syndrome, and overall reproductive endocrine function in women with BD have found high rates of HPG irregularities in women with BD. Second, there is evidence of reproductive dysfunction in women with BD prior to treatment. In addition, many of the psychotropic medications used in the treatment of BD are associated with weight gain, insulin resistance, and dyslipidemia. These metabolic side effects further compound the neuroendocrine system dysregulation in women with BD. Current understanding of the reproductive and metabolic function in women with BD points to vulnerability, which in turn increases the risk of later-life cardiovascular disease and diabetes, among other morbidities, for women with BD.

Obesity, serious mental illness and antipsychotic drugs

The prevalence of overweight and obesity is higher in people with mental illness than in the general population. Body weight is tightly regulated by a complex system involving the cortex and limbic system, the hypothalamus and the gastrointestinal tract. While there are justifiable concerns about the weight gain associated with antipsychotic medication, it is too simplistic to ascribe all obesity in people with serious mental illness (SMI) to their drug treatment. The development of obesity in SMI results from the complex interaction of the genotype and environment of the person with mental illness, the mental illness itself and antipsychotic medication. There are dysfunctional reward mechanisms in SMI that may contribute to poor food choices and overeating. While it is clear that antipsychotics have profound effects to stimulate appetite, no one receptor interaction provides an adequate explanation for this effect, and many mechanisms are likely to be involved. The complexity of the system regulating body weight allows us to start to understand why some individuals appear much more prone to weight gain and obesity than others.

Antipsychotic-induced body weight gain: predictors and a systematic categorization of the long-term weight course

OBJECTIVE

To explore the impact of premorbid and baseline body mass indices (BMIs) as well as BMI of patient's parents and associated variables on the prediction of antipsychotic-induced body weight gain.

METHODS

Retrospective/cross-sectional data of 65 patients receiving clozapine, olanzapine and/or risperidone were assessed according to a systematic categorization of the long-term (7.3+/-9.2 years) weight course and evaluated using descriptive, explorative correlation and regression analyses.

RESULTS

Increased values of parents' BMI (p=0.041) and patients' BMI at premorbid stage (p=0.039) and prior to first antipsychotic treatment (p=0.032) as well as female gender (p=0.012), younger age (p=0.005) and non-smoking (p=0.047) have the most predictive value on body weight gain under antipsychotic treatment including pre-treatment with typical antipsychotics. Weight gain under atypical antipsychotics (pre-treatment excluded) is predicted by an increased premorbid BMI (p=0.019). Conversely, a low BMI prior to first antipsychotic treatment predicts a higher acceleration of BMI change (p=0.008) in vulnerable individuals, but not total BMI change itself. Furthermore, a diagnosis of a schizophrenia spectrum disorder showed a trend towards the prediction of an increased atypical DeltaBMI (p=0.067), possibly due to a longer treatment duration with atypical antipsychotics (p<0.001).

DISCUSSION

The study indicates increased parents' BMI and patients' premorbid BMI, female gender, younger age and - as a trend - the diagnosis of a schizophrenia spectrum disorder to be predictors for antipsychotic-induced body weight gain involving atypical antipsychotics. Data contribute to the assumption of a strong impact of predispositional factors on weight gain, besides treatment-related factors.

Leptin and ghrelin levels in patients with schizophrenia during different antipsychotics treatment: a review

Energy homeostasis is achieved by the integration of peripheral metabolic signals by the neural circuits involving specific hypothalamic nuclei and brain stem regions. These neural circuits mediate many of the effects of the adipocyte-derived hormone leptin and gut-derived hormone ghrelin. The former is strongly anorexigenic while the latter is the only orexigenic agent active when administered by a peripheral route. Abnormal regulation of these 2 antagonistic regulatory peptides in patients with schizophrenia could play a role in the impairment in the regulation of food intake and energy balance. This bibliographical analysis aims to compare 27 prospective and cross-sectional studies published on circulating leptin and ghrelin levels during acute and chronic administration of antipsychotics treatment, especially atypical ones. Fasting morning leptin levels of schizophrenic patients increase rapidly in the first 2 weeks after atypical antipsychotic (AAP) treatment (mostly olanzapine and clozapine) and remain somehow elevated after that period up to several months. On the contrary, conventional antipsychotics (such as haloperidol) do not interfere with leptin levels. In contrast to leptin, fasting morning ghrelin levels decrease during the first few weeks after the beginning of AAPs treatment while they increase in the longer run. Surprisingly, body weight gain and correlations between the variation of these 2 peptides and adiposity and metabolism-related parameters such as the body mass index and abdominal perimeter were not systematically considered. Finally, an objective evaluation of feeding behavior during antipsychotic treatment remains to be determined.

Pharmacological management of atypical antipsychotic-induced weight gain

Excessive bodyweight gain was reported during the 1950s as an adverse effect of typical antipsychotic drug treatment, but the magnitude of bodyweight gain was found to be higher with the atypical antipsychotic drugs that were introduced after 1990. Clozapine and olanzapine produce the greatest bodyweight gain, ziprasidone and aripiprazole have a neutral influence, and quetiapine and risperidone cause an intermediate effect. In the CATIE study, the percentage of patients with bodyweight gain of >7% compared with baseline differed significantly between the antipsychotic drugs, i.e. 30%, 16%, 14%, 12% and 7% for olanzapine, quetiapine, risperidone, perphenazine (a typical antipsychotic) and ziprasidone, respectively (p<0.001). Appetite stimulation is probably a key cause of bodyweight gain, but genetic polymorphisms modify the bodyweight response during treatment with atypical antipsychotics. In addition to nutritional advice, programmed physical activity, cognitive-behavioural training and atypical antipsychotic switching, pharmacological adjunctive treatments have been assessed to counteract excessive bodyweight gain. In some clinical trials, nizatidine, amantadine, reboxetine, topiramate, sibutramine and metformin proved effective in preventing or reversing atypical antipsychotic-induced bodyweight gain; however, the results are inconclusive since few randomized, placebo-controlled clinical trials have been conducted. Indeed, most studies were short-term trials without adequate statistical power and, in the case of metformin, nizatidine and sibutramine, the results are contradictory. The tolerability profile of these agents is adequate. More studies are needed before formal recommendations on the use of these drugs can be made. Meanwhile, clinicians are advised to use any of these adjunctive treatments according to their individual pharmacological and tolerability profiles, and the patient's personal and family history of bodyweight gain and metabolic dysfunction.

Decreased levels of ghrelin, cortisol, and fasting blood sugar, but not n-octanoylated ghrelin, in Japanese schizophrenic inpatients treated with olanzapine

The mechanism by which chronic administration of olanzapine induces a marked weight gain in patients with schizophrenia remains unknown. We examined the influence of long-term treatment with olanzapine on plasma levels of hormones regulating food intake and energy homeostasis in schizophrenia. In this study, olanzapine was administered to 28 Japanese inpatients for 16 weeks after switching from typical antipsychotic drugs or risperidone. At endpoint, no significant changes in body weight or body mass index were found. There was a significant decrease in the plasma levels of ghrelin without any accompanying change in active, n-octanoylated ghrelin. Serum levels of leptin tended to be increased and a significant reduction in plasma cortisol levels was found. In addition, the levels of fasting blood sugar as well as free fatty acid were significantly decreased. Furthermore, we did not confirm any marked weight gain induced by chronic administration of olanzapine as previously reported. The reason for this discrepancy may be due to differences in subjects and treatment settings. Based on these findings, it is unlikely that the decrease in plasma ghrelin levels by chronic administration of olanzapine affects weight gain. Further studies examining the effect of chronic olanzapine administration on weight and energy homeostasis in inpatients are required.

Effect of antipsychotics on peptides involved in energy balance in drug-naive psychotic patients after 1 year of treatment

Weight gain has become one of the most common and concerning side effects of antipsychotic treatment. The mechanisms whereby antipsychotics induce weight gain are not known. It has been suggested that peptides related to food intake and energy balance could play a role in weight gain secondary to antipsychotic therapy. To better understand the pathophysiology of antipsychotic-induced weight gain, we studied the effects of 3 antipsychotic drugs (haloperidol, olanzapine, and risperidone) on peptides involved in energy balance (insulin, ghrelin, leptin, adiponectin, visfatin, and resistin) in a population of drug-naive patients with first episode of psychosis.A significant increase in weight (10.16 kg [SD, 8.30 kg]; P < 0.001), body mass index (3.56 kg/m [SD, 2.89 kg/m]; P < 0.001), and fasting insulin (3.93 muU/mL [SD, 3.93 muU/mL]; P = 0.028), leptin (6.76 ng/mL [SD, 7.21 ng/mL]; P < 0.001), and ghrelin (15.47 fmol/mL [SD, 47.90 fmol/mL]; P = 0.009) plasma levels were observed. The increments in insulin and leptin concentrations were highly correlated with the increment in weight and body mass index and seem to be a consequence of the higher fat stores. The unexpected increase in ghrelin levels might be related with the causal mechanism of weight gain induced by antipsychotics. Finally, the 3 antipsychotics had similar effects in all parameters evaluated.

Antipsychotic induced weight gain in schizophrenia:mechanisms and management

The aim of the present paper was to describe the mechanisms and management of antipsychotic-induced weight gain in schizophrenia patients. A comprehensive literature review of all available articles on the mechanisms and management of antipsychotic-induced weight gain was done by searching databases PsychINFO and PubMed. A summary of the available guidelines for monitoring of antipsychotic-induced weight gain and metabolic syndrome is also provided. There has been a substantial increase in the number of studies investigating the mechanisms and management of antipsychotic-induced weight gain after 2002. These include advances in the understanding of pharmacogenomics of weight gain and several randomized controlled trials (RCTs) evaluating pharmacological and psychological treatments to promote weight loss. The most effective strategy for prevention of weight gain is the choice of antipsychotic medication with low weight gain potential. In individuals with established weight gain and metabolic issues, switching to an antipsychotic agent with lower weight gain potential and/or lifestyle modifications with physical activity are most effective in promoting weight loss. Pharmacological agents such as orlistat and sibutramine are effective in general obesity but have not been sufficiently evaluated in antipsychotic-induced weight gain. The case to prescribe routine pharmacological treatment to promote weight loss is weak. Long-term, pragmatic studies are required to inform clinical practice. Weight gain in schizophrenia is associated with significant physical and psychological morbidity. Achieving an optimal trade-off between effectiveness and side-effects of antipsychotic agents, although difficult, is achievable. This should be based on three main principles: (i) a shared decision-making model between the patient, clinician and carer(s) when choosing an antipsychotic; (ii) a commitment to baseline and follow-up monitoring with explicit identification of the responsible individual or team; and (iii) the adoption of clear structured protocols for clinicians to follow in case of clinically significant weight gain and metabolic issues, which should incorporate greater collaboration between various health professionals from psychiatric and medical specialist services.

Impact of atypical antipsychotic therapy on leptin, ghrelin, and adiponectin

BACKGROUND

Many adverse effects of atypical antipsychotic treatment are associated with antagonism of monoamine receptors; however, data indicate that important metabolic effects, such as hypertriglyceridemia and impairment in glucose/insulin homeostasis, may not be related to these mechanisms, leading investigators to explore alternative hypotheses. Promising candidates include a possible impact of antipsychotics on peptide hormonal regulators of metabolic control such as leptin, ghrelin, and adiponectin. The purpose of this review is to summarize recent data on changes in these hormones during atypical antipsychotic treatment.

METHODS

A Medline search was performed for papers published from January 1999 to January 2007 using key words antipsychotic, atypical antipsychotic, and individual atypical antipsychotic drug names cross-referenced with leptin, ghrelin, and adiponectin.

RESULTS

The bulk of the published work focused on changes in body weight and serum leptin, with far less data on ghrelin, and adiponectin, and nonweight metabolic changes. Leptin changes were directly related to a medication's weight gain liability, with no added antipsychotic effects on leptin signaling. Conflicting results emerged for the other markers, but all three long-term studies on ghrelin showed increased levels in patients on atypical antipsychotics with weight gain liabilities.

CONCLUSIONS

Leptin increases during antipsychotic treatment are a result of weight gain rather than a direct impact of atypical antipsychotics on leptin physiology. Preliminary long-term data show increased ghrelin levels, but this finding must be replicated. The association with antipsychotic effects on glucose and lipid metabolism and these hormones remains virtually unstudied. Future research should indicate whether ghrelin and other peptide hormones may be useful predictors of weight gain or metabolic changes in patients on antipsychotics.

A comparison of the effects of olanzapine and risperidone versus placebo on ghrelin plasma levels

To thoroughly investigate the phenomenon of atypical antipsychotic-associated weight gain, a feeding laboratory paradigm was developed that included obtaining plasma levels of the orexigenic peptide ghrelin that is associated with appetite and eating. This study is a randomized, double-blind, parallel group trial comparing the effects of a 2-week exposure to olanzapine, risperidone, or placebo on plasma ghrelin area under the plasma-time curve (AUC) in 28 healthy human subjects. Subjects were randomized to receive olanzapine, risperidone, or placebo and titrated over 4 days to 10 mg/d or 4 mg/d, respectively. The mean dose at end point was 8.6 + 1.8 mg/d for the olanzapine group and 2.8 + 0.8 mg/d for the risperidone group. Weight changes were significantly different between groups at end point (F2,44 = 10.193; P = 0.0001). The olanzapine group demonstrated a significant increase in weight at end point (2.25 + 1.84 kg) compared with placebo (0.13 + 1.05 kg; P = 0.007). Because of the small subject number, the comparisons between olanzapine and risperidone and risperidone and placebo did not reach statistical significance, although olanzapine's mean weight gain was numerically greater than that of risperidone (2.25 + 1.84 kg vs 1.10 + 0.99 kg) and risperidone's mean weight gain was numerically larger than placebo (1.10 + 0.99 kg vs 0.13 + 1.05 kg). The baseline adjusted Bonferroni corrected contrast of end point ghrelin AUC demonstrated a significant difference between groups (F2,24 = 4.40; P = 0.024), and the post hoc analysis revealed a significant decrease in ghrelin AUC for the olanzapine group in comparison with the risperidone group (P = 0.021) but not between risperidone and placebo or olanzapine and placebo. Ghrelin AUC values did not change significantly from baseline to end point in either of the other 2 groups. The difference between groups approached but did not reach significance (F2,23 = 3.299; P = 0.055) when body mass index change was included as a covariate, suggesting that the difference in ghrelin AUC change followed the change in body weight. Sedation associated with both active drugs (P = 0.006) and "stuffy nose" associated with risperidone (P = 0.020) were the only statistically different adverse reactions when compared with placebo. Thus, a human feeding laboratory paradigm using a brief exposure to atypical antipsychotics functions as a method to investigate pharmacologically induced weight gain and its association with changes in the orexigenic peptide ghrelin. This rejects the hypothesis that ghrelin levels are elevated by the antipsychotic and that this is a potential cause of the weight gain phenomenon.

Abnormalities in glucose metabolism in patients with schizophrenia treated with atypical antipsychotic medications

The incidence of carbohydrate intolerance and overt diabetes is increased in patients with schizophrenia treated with the newer atypical antipsychotic agents. The precise mechanism for these abnormalities remains obscure. This review examines the potential interaction between atypical antipsychotic medications and several hormones known to influence appetite regulation and carbohydrate metabolism.

Atypische Neuroleptika und metabolisches Syndrom

The introduction of atypical antipsychotics in psychopharmacology represented a major advance in the treatment of psychotic disorders. However, there have been numerous studies that certain atypical antipsychotics may be associated with a greater risk of metabolic abnormalities than others, including weight gain, hyperlipidemia and new-onset typ 2 diabetes mellitus. A G-Protein beta3 subunit Gen (C825T) polymorphism, an increased carbohydrate metabolism and dyshormonism are discussed as pathogenetic mechanisms. High risk patients (adiposity, hyperlipidaemia, hyperglycaemia, preexisting diabetes) should maintain an antipsychotic agent with a favourable side effect profile. In these cases a periodical diabetes screening and blood lipid controls are required. Clinicans must balance the significant benefits of atypical antipsychotics against the risk of metabolic disturbances. In this article recent findings are reviewed.

Changes in neuroendocrine and metabolic hormones induced by atypical antipsychotics in normal-weight patients with schizophrenia

CONTEXT

Atypical antipsychotics (SGA) have the propensity to induce weight gain.

OBJECTIVE

The aim was to evaluate early changes in hormones involved in neuroendocrine regulations (serum cortisol, growth hormone and prolactin) and positive energy balance (serum insulin, leptin and ghrelin) during SGA treatment in normal-weight patients with schizophrenia with the purpose of exploring the possibility to combat weight gain early through manipulation of circulating hormone levels.

DESIGN

We conducted a randomized, partly cross-sectional and partly longitudinal, prospective study.

SETTING AND PATIENTS

Eighteen normal-weight in-patients with schizophrenia treated with FGA (first-generation antipsychotics) were referred to the Institute of Psychiatry. Twenty age-, gender- and BMI-matched healthy subjects were investigated at the Neuroendocrine Unit, Belgrade University.

INTERVENTION

Oral glucose tolerance test (OGTT) was performed at baseline in all and then 13 patients were assigned to receive SGA (risperidone or clozapine) and OGTT was repeated after 1 and 3 months.

RESULTS

At baseline, patients with schizophrenia had higher peak glucose levels (p < 0.05), glucose area under the curve (AUC; p < 0.05), peak insulin levels (p < 0.05), insulin AUC values during OGTT (p < 0.01) and the calculated homeostasis model assessment (HOMA-IR) value than control subjects (p < 0.05). Patients with schizophrenia showed higher morning cortisol (p < 0.05) levels than control subjects. After 1 and 3 months of SGA therapy patients with schizophrenia gained bodyweight by 3.5 and 8.6%, respectively. Leptin levels steadily increased while cortisol levels decreased in the first month and remained so. Serum glucose, insulin and ghrelin levels on SGA were similar as at baseline. Circulating ghrelin levels decreased after OGTT during SGA which is consistent with a role for ghrelin in the initiation of meals.

CONCLUSIONS

Treatment with SGA was associated with continuous weight gain, with an early increase in serum leptin levels and decrease in cortisol levels. Elevated circulating leptin was ineffective in the control of fat deposition. Similar plasma ghrelin levels and similar decrease pattern of ghrelin after OGTT compared to healthy subjects signify intact meal-promoting effects of ghrelin during SGA therapy, which at the same time renders anorexigenic pathways ineffective. This may lead to weight gain and further studies with a ghrelin antagonist may provide support for this hypothesis.

Genetics of antipsychotic treatment emergent weight gain in schizophrenia

Classic and modern antipsychotics can induce substantial weight gain causing diabetes, lipid abnormalities and psychological distress. Treatment emergent weight gain varies within the broad class of antipsychotics; however, an individual's propensity to develop weight gain largely depends on genetic factors. The first part of this review highlights current ideas and concepts related to antipsychotic-induced weight gain, including principles on energy homeostasis. The second part summarizes genetic findings emphasizing studies published after 2003 as prior studies have been reviewed in detail elsewhere. Candidate gene studies have produced significant findings in the 5-hydroxytryptamin 2C (5HT2C) and adrenergic alpha2a (ADRalpha2a) receptor genes, as well as in the leptin, guanine nucleotide binding protein (GNB3) and synaptomal-associated protein 25kDa (SNAP25) genes. Results from genome-wide association and linkage studies point to several chromosomal regions (e.g., 12q24) and some specific genes (e.g., promelanin concentrating hormone [PMCH], polycyctic kidney and hepatic disease 1 [PKHD1], peptidylglycine alpha-amidating monooxygenase [PAM]). However, more efforts are needed before risk prediction and personalized medicine can be made available for antipsychotic-induced weight gain.

Cytokines in schizophrenia and the effects of antipsychotic drugs

Growing evidence suggests that the immune, endocrine, and nervous systems interact with each other through cytokines, hormones, and neurotransmitters. The activation of the cytokine systems may be involved in the neuropathological changes occurring in the central nervous system (CNS) of schizophrenic patients. Numerous studies report that treatment with antipsychotic drugs affects the cytokine network. Hence, it is plausible that the influence of antipsychotics on the cytokine systems may be responsible for their clinical efficacy in schizophrenia. This article reviews current data on the cytokine-modulating potential of antipsychotic drugs. First, basic information on the cytokine networks with special reference to their role in the CNS as well as an up-to-date knowledge of the cytokine alterations in schizophrenia is outlined. Second, the hitherto published studies on the influence of antipsychotics on the cytokine system are reviewed. Third, the possible mechanisms underlying antipsychotics' potential to influence the cytokine networks and the most relevant aspects of this activity are discussed. Finally, limitations of the presented studies and prospects of future research are delineated.

Food intake and reward mechanisms in patients with schizophrenia: implications for metabolic disturbances and treatment with second-generation antipsychotic agents

Obesity is highly prevalent among patients with schizophrenia and is associated with detrimental health consequences. Although excessive consumption of fast food and pharmacotherapy with such second-generation antipsychotic agents (SGAs) as clozapine and olanzapine has been implicated in the schizophrenia/obesity comorbidity, the pathophysiology of this link remains unclear. Here, we propose a mechanism based on brain reward function, a relevant etiologic factor in both schizophrenia and overeating. A comprehensive literature search on neurobiology of schizophrenia and of eating behavior was performed. The collected articles were critically reviewed and relevant data were extracted and summarized within four key areas: (1) energy homeostasis, (2) food reward and hedonics, (3) reward function in schizophrenia, and (4) metabolic effects of the SGAs. A mesolimbic hyperdopaminergic state may render motivational/incentive reward system insensitive to low salience/palatability food. This, together with poor cognitive control from hypofunctional prefrontal cortex and enhanced hedonic impact of food, owing to exaggerated opioidergic drive (clinically manifested as pain insensitivity), may underlie unhealthy eating habits in patients with schizophrenia. Treatment with SGAs purportedly improves dopamine-mediated reward aspects, but at the cost of increased appetite and worsened or at least not improved opiodergic capacity. These effects can further deteriorate eating patterns. Pathophysiological and therapeutic implications of these insights need further validation via prospective clinical trials and neuroimaging studies.

No evidence for binding of clozapine, olanzapine and/or haloperidol to selected receptors involved in body weight regulation

The underlying mechanisms of antipsychotic (AP)-induced weight gain are unknown, but both central and peripheral AP target receptors could potentially be involved. This study used radioligand binding assays to compare the binding affinities of clozapine, olanzapine and haloperidol for candidate receptors potentially involved in AP-induced weight gain. Selected candidates derived from known pathways involved in body weight regulation included receptors classified as anorexigenic (bombesin receptor subtype 3, calcitonin gene-related peptide receptor, cholecystokinin receptor, melanocortin-4 receptor, neurotensin receptor 1) or orexigenic (cannabinoid receptor 1, galanin 1 receptor, melanin-concentrating hormone receptor (MCHR), neuropeptide Y1 receptor) as well as receptors involved in physiological actions related to digestion and fluid homeostasis (angiotensin II type 1 receptor, bradykinin B2 receptor, endothelin receptor, neurokinin 1 receptor, vasoactive intestinal polypeptide receptor 1). Clozapine, olanzapine and haloperidol exhibited negligible affinities to all of these receptors except for the MCHR (Ki=501 nM; haloperidol). With respect to other candidates from (neuro)transmitter systems already suggested to be involved in AP-induced weight gain, the binding profile of olanzapine resembled that of clozapine, with high affinity (Ki<10 nM) for serotonin (5-HT) 5-HT2A, 5-HT2C and 5-HT6, muscarinic M1 and histamine H1 receptors. In contrast, the binding profile of haloperidol was substantially different (high affinity only for the dopamine D1 receptor). In conclusion, we have not identified a novel binding site of the two investigated atypical AP that could contribute to the induced weight gain.