Metabolic side effects of antipsychotic drug treatment--pharmacological mechanisms

The use of antipsychotics in preschoolers: a veto or a sensible last option?

Recent reports have illustrated a dramatic rise in the use of antipsychotics in preschool children, medications originally designed and licensed for the treatment of adult psychotic disorders. Within this context, the current usage and the associated diagnoses are reviewed and compared with official guidelines and licensing for such use, highlighting a controversial challenge for clinicians. A review of the evidence base of the relative efficacy of such medications for a range of disorders is given. Associated safety and side effects are discussed, with compelling evidence for increased adverse events associated with use of antipsychotics in preschoolers, and neurodevelopmental hypotheses are used to guide predictions of long-term risk. An apparent gap in the literature and evidence base supporting such use and elucidating the risks and benefits leaves a challenge for clinicians and researchers and hinders the development of appropriate guidelines. Pragmatism in clinical practice, mindful of the limited evidence base that does exist and the propensity for harm, is necessary; far more research is required in this important area.

ADN-1184 a monoaminergic ligand with 5-HT(6/7) receptor antagonist activity: pharmacological profile and potential therapeutic utility

BACKGROUND AND PURPOSE

Many dementia patients exhibit behavioural and psychological symptoms (BPSD) that include psychosis, aggressivity, depression and anxiety. Antipsychotic drugs are frequently prescribed but fail to significantly attenuate mood deficits, may interfere with cognitive function and are associated with motor and cardiac side effects, which are problematic in elderly patients. A need therefore exists for drugs that are better suited for the treatment of BPSD.

EXPERIMENTAL APPROACH

We used in vitro cellular and in vivo behavioural tests to characterize ADN-1184, a novel arylsulfonamide ligand with potential utility for treatment of BPSD.

KEY RESULTS

ADN-1184 exhibits substantial 5-HT6 /5-HT7 /5-HT2A /D2 receptor affinity and antagonist properties in vitro. In tests of antipsychotic-like activity, it reversed MK-801-induced hyperactivity and stereotypies and inhibited conditioned avoidance response (MED = 3 mg·kg(-1) i.p.). Remarkably, ADN-1184 also reduced immobility time in the forced swim test at low doses (0.3 and 1 mg·kg(-1) i.p.; higher doses were not significantly active). Notably, up to 30 mg·kg(-1) ADN-1184 did not impair memory performance in the passive avoidance test or elicit significant catalepsy and only modestly inhibited spontaneous locomotor activity (MED = 30 mg·kg(-1) i.p.).

CONCLUSIONS AND IMPLICATIONS

ADN-1184 combines antipsychotic-like with antidepressant-like properties without interfering with memory function or locomotion. This profile is better than that of commonly used atypical antipsychotics tested under the same conditions and suggests that it is feasible to identify drugs that improve BPSD, without exacerbating cognitive deficit or movement impairment, which are of particular concern in patients with dementia.

Association of ADRA2A and MTHFR gene polymorphisms with weight loss following antipsychotic switching to aripiprazole or ziprasidone

OBJECTIVES

Various genetic polymorphisms have been reported to be associated with antipsychotic-induced weight gain. In this study, we aimed to determine whether risk polymorphisms in 12 candidate genes are associated with reduction in body mass index (BMI) of patients following switching of antipsychotics to aripiprazole or ziprasidone.

METHODS

We recruited 115 schizophrenia patients with metabolic abnormalities and who have been on at least 1 year treatment with other antipsychotics; they were then switched to either aripiprazole or ziprasidone. They were genotyped, and their BMI monitored for 6 months.

RESULTS

Significant associations with reduction in BMI at 6 months following switching were found in two of these genes: with rs1800544 of the ADRA2A gene (CC + CG [-0.32 ± 1.41 kg/m²] vs GG [-1.04 ± 1.63 kg/m²], p = 0.013) and with rs1801131 of the MTHFR gene (AA [-0.36 ± 1.53] vs AC + CC [-1.07 ± 1.53], p = 0.015).

CONCLUSION

The study data indicated that carriage of the ADRA2A rs1800544 GG genotype and the MTHFR rs1801131 C allele are associated with BMI reduction in this population following switching of antipsychotics to aripiprazole and ziprasidone.

Eating disorders in schizophrenia: implications for research and management

Objective. Despite evidence from case series, the comorbidity of eating disorders (EDs) with schizophrenia is poorly understood. This review aimed to assess the epidemiological and clinical characteristics of EDs in schizophrenia patients and to examine whether the management of EDs can be improved. Methods. A qualitative review of the published literature was performed using the following terms: "schizophrenia" in association with "eating disorders," "anorexia nervosa," "bulimia nervosa," "binge eating disorder," or "night eating syndrome." Results. According to our literature review, there is a high prevalence of comorbidity between schizophrenia and EDs. EDs may occur together with or independent of psychotic symptoms in these patients. Binge eating disorders and night eating syndromes are frequently found in patients with schizophrenia, with a prevalence of approximately 10%. Anorexia nervosa seems to affect between 1 and 4% of schizophrenia patients. Psychopathological and neurobiological mechanisms, including effects of antipsychotic drugs, should be more extensively explored. Conclusions. The comorbidity of EDs in schizophrenia remains relatively unexplored. The clearest message of this review is the importance of screening for and assessment of comorbid EDs in schizophrenia patients. The management of EDs in schizophrenia requires a multidisciplinary approach to attain maximized health outcomes. For clinical practice, we propose some recommendations regarding patient-centered care.

Olanzapine depot formulation in rat: a step forward in modelling antipsychotic-induced metabolic adverse effects

Rats are used as animal models in the study of antipsychotic-induced metabolic adverse effects, with oral drug administration yielding hyperphagia, weight gain and, in some cases, lipogenic effects. However, the rapid half-life of these drugs in rats, in combination with development of drug tolerance after a few weeks of treatment, has limited the validity of the model. In order to prevent fluctuating drug serum concentrations seen with daily repeated administrations, we injected female rats with a single intramuscular dose of long-acting olanzapine formulation. The olanzapine depot injection yielded plasma olanzapine concentrations in the range of those achieved in patients, and induced changes in metabolic parameters similar to those previously observed with oral administration, including increased food intake, weight gain and elevated plasma triglycerides. Moreover, the sensitivity to olanzapine was maintained beyond the 2-3 wk of weight gain observed with oral administration. In a separate olanzapine depot experiment, we aimed to clarify the role of hypothalamic AMP-activated protein kinase (AMPK) in olanzapine-induced weight gain, which has been subject to debate. Adenovirus-mediated inhibition of AMPK was performed in the arcuate (ARC) or the ventromedial hypothalamic (VMH) nuclei in female rats, with subsequent injection of olanzapine depot solution. Inhibition of AMPK in the ARC, but not in the VMH, attenuated the weight-inducing effect of olanzapine, suggesting an important role for ARC-specific AMPK activation in mediating the orexigenic potential of olanzapine. Taken together, olanzapine depot formulation provides an improved mode of drug administration, preventing fluctuating plasma concentrations, reducing handling stress and opening up possibilities to perform complex mechanistic studies.

Improving metabolic and cardiovascular health at an early psychosis intervention program in vancouver, Canada

Psychotic disorders most commonly appear during the late teenage years and early adulthood. A focused and rapid clinical response by an integrated health team can help to improve the quality of life of the patient, leading to a better long-term prognosis. The Vancouver Coastal Health early psychosis intervention program covers a catchment area of approximately 800,000 people in the cities of Vancouver and Richmond, Canada. The program provides a multidisciplinary approach to supporting patients under the age of 30 who have recently experienced first-break psychosis. The program addresses the needs of the treatment environment, medication, and psychological therapies. A critical part of this support includes a program to specifically improve patients' physical health. Physical health needs are addressed through a two-pronged, parallel approach. Patients receive routine metabolic health assessments during their first year in the program, where standard metabolic parameters are recorded. Based on the results of clinical interviews and laboratory tests, specific actionable interventions are recommended. The second key strategy is a program that promotes healthy lifestyle goal development. Patients work closely with occupational therapists to develop goals to improve cardiometabolic health. These programs are supported by an active research environment, where patients are able to engage in studies with a focus on improving their physical health. These studies include a longitudinal evaluation of the effects of integrated health coaching on maintaining cardiometabolic health in patients recently admitted to the program, as well as a clinical study that evaluates the effects of low versus higher metabolic risk antipsychotic drugs on central adiposity. An additional pharmacogenomic study is helping to identify genetic variants that may predict cardiometabolic changes following treatment with antipsychotic drugs.

In vivo pharmacological evaluations of novel olanzapine analogues in rats: a potential new avenue for the treatment of schizophrenia

Olanzapine (Olz) is one of the most effective antipsychotic drugs commonly used for treating schizophrenia. Unfortunately, Olz administration is associated with severe weight gain and metabolic disturbances. Both patients and clinicians are highly interested in the development of new antipsychotics which are as effective as atypical antipsychotics but which have a lower propensity to induce metabolic side effects. In the present study, we examined two new derivatives of Olz; OlzEt (2-ethyl-4-(4'-methylpiperazin-1'-yl)-10Hbenzo[b]thieno[2,3-e][1,4]diazepine), and OlzHomo (2-ethyl-4-(4'-methyl-1',4'-diazepan-1'-yl)-10H-benzo[b]thieno[2,3-e] [1,4]diazepine), for their tendency to induce weight gain in rats. Weight gain and metabolic changes were measured in female Sprague Dawley rats. Animals were treated orally with Olz, OlzEt, OlzHomo (3 or 6 mg/kg/day), or vehicle (n = 8), three times daily at eight-hour intervals for 5 weeks. Furthermore, a phencyclidine (PCP)-treated rat model was used to examine the prevention of PCP-induced hyperlocomotor activity relevant for schizophrenia therapy. Male Sprague Dawley rats were pre-treated with a single dose (3 mg/kg/day) of Olz, OlzEt, OlzHomo, or vehicle (n = 12), for 2 weeks. Locomotor activity was recorded following a subcutaneous injection with either saline or PCP (10 mg/kg). Olz was found to induce weight gain, hyperphagia, visceral fat accumulation, and metabolic changes associated with reduced histamatergic H1 receptor density in the hypothalamus of treated rats. In contrast, OlzEt and OlzHomo presented promising antipsychotic effects, which did not induce weight gain or fat deposition in the treated animals. Behavioural analysis showed OlzEt to attenuate PCP-induced hyperactivity to a level similar to that of Olz; however, OlzHomo showed a lower propensity to inhibit these stereotyped behaviours. Our data suggest that the therapeutic effectiveness of OlzHomo may be delivered at a higher dose than that of Olz and OlzEt. Overall, OlzEt and OlzHomo may offer a better pharmacological profile than Olz for treating patients with schizophrenia. Clinical trials are needed to test this hypothesis.

Psychiatric medication refill practices of juvenile detainees

To examine the psychiatric medication fill rates of adolescents after release from juvenile detention. The team reviewed 177 charts. A fill was defined as a psychiatric medication charge to Medicaid 30- or 90-days after release. Differences in demographic characteristics were compared among individuals with fills at 30- or 90-days and those with no medication fills. Forty-five percent of patients were on at least one psychiatric medication. Among detainees on a psychiatric medication, 62 % had a fill by 30 days after release, and 78 % by 90 days. At least 50 % of the adolescents on a psychiatric medication were on an atypical antipsychotic. There was no significant relationship between medication fill and race, age, or sex. Despite the known associations between mental health diagnosis and treatment-seeking with age, sex, and race, it appears that psychiatric medication fill patterns after release from detention are not associated with these factors.

Second generation antipsychotic-induced type 2 diabetes: a role for the muscarinic M3 receptor

Second generation antipsychotics (SGAs) are widely prescribed to treat various disorders, most notably schizophrenia and bipolar disorder; however, SGAs can cause abnormal glucose metabolism that can lead to insulin-resistance and type 2 diabetes mellitus side-effects by largely unknown mechanisms. This review explores the potential candidature of the acetylcholine (ACh) muscarinic M3 receptor (M3R) as a prime mechanistic and possible therapeutic target of interest in SGA-induced insulin dysregulation. Studies have identified that SGA binding affinity to the M3R is a predictor of diabetes risk; indeed, olanzapine and clozapine, SGAs with the highest clinical incidence of diabetes side-effects, are potent M3R antagonists. Pancreatic M3Rs regulate the glucose-stimulated cholinergic pathway of insulin secretion; their activation on β-cells stimulates insulin secretion, while M3R blockade decreases insulin secretion. Genetic modification of M3Rs causes robust alterations in insulin levels and glucose tolerance in mice. Olanzapine alters M3R density in discrete nuclei of the hypothalamus and caudal brainstem, regions that regulate glucose homeostasis and insulin secretion through vagal innervation of the pancreas. Furthermore, studies have demonstrated a dynamic sensitivity of hypothalamic and brainstem M3Rs to altered glucometabolic status of the body. Therefore, the M3R is in a prime position to influence glucose homeostasis through direct effects on pancreatic β-cells and by potentially altering signalling in the hypothalamus and brainstem. SGA-induced insulin dysregulation may be partly due to blockade of central and peripheral M3Rs, causing an initial disruption to insulin secretion and glucose homeostasis that can progressively lead to insulin resistance and diabetes during chronic treatment.

Metabolic syndrome: relative risk associated with post-traumatic stress disorder (PTSD) severity and antipsychotic medication use

BACKGROUND

In recent years, numerous lines of converging evidence have revealed an association between post-traumatic stress disorder (PTSD) and impaired physical health outcomes, including cardiovascular disease and metabolic syndrome. Although these findings have been interpreted as indicating a direct association of PTSD with metabolic syndrome and obesity, previous studies have not addressed the important confound of antipsychotic drug usage in this population. Second generation antipsychotic medications themselves are associated with metabolic syndrome and obesity, and it is unclear whether the common utilization of these drugs in PTSD may account for some if not all of the observed metabolic problems.

OBJECTIVE

The present study examined the relative contributions of PTSD severity and use of antipsychotic medications to risk of metabolic syndrome among veterans.

METHOD

Cross-sectional clinical data, including five factors representing metabolic syndrome, psychiatric diagnoses, and medications were gathered from 253 veterans enrolling in mental health services. We used a logistic regression model to measure the relative association of antipsychotic medication use and PTSD severity on risk of metabolic syndrome.

RESULTS

We found that antipsychotic medication usage was not uniquely associated with elevated risk of metabolic syndrome (Wald = 0.30, ns) when PTSD severity and other sociodemographic, psychiatric, and behavioral variables were accounted for. Furthermore, PTSD severity continued to be a significant and unique predictor of risk for metabolic syndrome (Wald = 4.04, p < 0.05).

CONCLUSIONS

These findings suggest that chronic and moderately severe PTSD, independent of antipsychotic medications, is associated with increased risk of metabolic syndrome.

Metabolic syndrome: differences between psychiatric and internal medicine patients

OBJECTIVES

The existence of specific features of Metabolic Syndrome (MetS) in psychiatric population in comparison to not psychiatric patients has not been systematically investigated. The purpose of this study is to evaluate the differences of MetS among a group of psychiatric patients and a group of internal medicine patients in terms of anthropometric measurements, biochemical variables, and cardiovascular risk.

METHODS

We enrolled 83 psychiatric inpatients under pharmacological treatment (schizophrenia n = 24, bipolar disorder n = 27, major depression n = 14, other n = 18) and 77 internal medicine patients visited for supposed MetS as affected by overweight or arterial hypertension.

RESULTS

Psychiatric patients differed from control subjects by age (yrs) (47 +/- 9 vs. 52 +/- 8.6, p = 0.001), waist circumference (cm) (111.9 +/- 10.9 vs. 106 +/- 12.6, p = 0.02), HDL cholesterol (mg/dl) (36.8 +/- 7 vs. 48 +/- 11.3, p = 0.001), serum insulin (microU/ml) (26 +/- 12.5 vs. 16.4 +/- 8.8, p = 0.001), triglyceride/HDL cholesterol ratio (4.8 +/- 2.7 vs. 3.3 +/- 2.2, p = 0.01). Female psychiatric patients had higher levels of triglycerides (mg) (178 + 86 vs. 115 + 53, p = 0.002) and of HOMA index (7.8 + 5 vs. 3.8 + 3.3, p = 0.005). Triglycerides and triglycerides/HDL ratio levels were higher in Unipolar Depression. A positive association was found between antidepressant drug treatment with triglycerides and triglycerides/HDL ratio levels, neuroleptic treatment with the HOMA index, and antipsychotics drugs with the Framingham index.

LIMITATIONS

Psychiatric study population numerosity and duration of psychiatric illness and drug treatment.

CONCLUSIONS

Specific features of MetS in psychiatric population are mainly represented by young age of onset, hyperinsulinemia, increased abdominal adiposity, and low HDL cholesterol whose common denominator may be insulin-resistance.

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.

Weight gain in risperidone therapy: investigation of peripheral hypothalamic neurohormone levels in psychotic patients

The use of antipsychotic drugs has started a new era in the treatment of psychotic disorders. Nevertheless, they cause complications in the long-term treatment, which is mainly weight gain. In this study, we investigated circulating levels of hypothalamic neuropeptides, which are related to appetite regulation, neuropeptide Y (NPY), α-melanocyte-stimulating hormone (α-MSH), cocaine- and amphetamine-regulated transcript (CART), and leptin, in first-attack psychotic patients who were treated with an atypical antipsychotic drug, risperidone, for 4 weeks. We used a case-control association design to compare the neuropeptides in the control group versus before and after treatment of the patient group. Samples were obtained from psychotic patients who were admitted to the Psychiatry Outpatient Clinics, Gulhane School of Medicine, Ankara, Turkey. When compared with the control group, NPY and α-MSH plasma levels of psychotic patients were severely reduced, and the CART levels were substantially increased when they were first diagnosed (before treatment). However, the patients' body mass index and circulating leptin levels were markedly high after the treatment. Circulating levels of those neurohormones were not significantly changed between before and after treatment of the patients. These data demonstrate that peripheral α-MSH and NPY, although reflecting only secretion from peripheral organs, nevertheless, may provide an insight into the patients sympathetic tone and also suggest change of their appetite regulation. α-Melanocyte-stimulating hormone, NPY, and CART plasma levels may be used as a predictor of weight gain in the early treatment of the patients along with the leptin levels.

Determinants of physical health parameters in individuals with intellectual disability who use long-term antipsychotics

Individuals with intellectual disability frequently use antipsychotics for many years. This may have detrimental health effects, including neurological symptoms and metabolic and hormonal dysregulation, the latter possibly affecting bone metabolism. There is large variability in the degree in which antipsychotic agents lead to these health problems. In the current study we investigated potential determinants of physical symptoms and biological parameters known to be associated with use of antipsychotics in a convenience sample of 99 individuals with intellectual disability who had used antipsychotics for more than one year for behavioural symptoms. We focused on extrapyramidal symptoms; on overweight and presence of components of the metabolic syndrome; and on elevated plasma prolactin and bone turnover parameters. As predictor variables, we used patient (sex, age, genetic polymorphisms, and severity of intellectual disability) and medication use (type and dosage) characteristics. We found extrapyramidal symptoms to be present in 53%, overweight or obesity in 46%, and the metabolic syndrome in 11% of participants. Hyperprolactineaemia and one or more elevated bone turnover markers were present in 17% and 25%, respectively. Higher age and more severe intellectual disability were associated with dyskinesia and a higher dosage of the antipsychotic drug was associated with parkinsonism. Less severe intellectual disability was related to higher Body Mass Index. Use of atypical antipsychotics was associated with higher diastolic blood pressure and elevated fasting glucose. Clinicians who prescribe antipsychotics in individuals with intellectual disability should carefully balance the potential benefits of prolonged treatment against the risk of health hazards associated with the use of antipsychotics.

Effects of controlled discontinuation of long-term used antipsychotics on weight and metabolic parameters in individuals with intellectual disability

Antipsychotics are frequently prescribed agents in individuals with intellectual disability, often for behavioral symptoms. Efficacy of antipsychotics for this is ambiguous, so discontinuation should be considered. Weight gain and metabolic dysregulation are well-known adverse effects of antipsychotics which increase the risk of the metabolic syndrome. We performed a discontinuation study in 99 adults with intellectual disability, living in residential facilities who used antipsychotics for behavioral symptoms for more than 1 year. The aim of the present study was to investigate the effects of discontinuation of long-term used antipsychotics on weight, body mass index (BMI), and parameters of the metabolic syndrome and to investigate the influence of genetic polymorphisms and medication factors on these outcomes. Discontinuation of antipsychotics led to a mean decrease of 4 cm waist circumference, of 3.5 kg weight, 1.4 kg/m2 BMI, and 7.1 mm Hg systolic blood pressure. In those participants who had not completely discontinued use of antipsychotics we found a decrease in weight and BMI and an increase in fasting glucose. The presence of the C-allele of serotonin 5-hydroxytryptamine receptor polymorphism rs141334 was associated with higher waist circumference and higher plasma levels of triglycerides and lower levels of high-density lipoprotein. Achievement of complete discontinuation predicted a larger decrease in waist circumference and BMI. In conclusion, results of the study show the beneficial effects of discontinuation of long-term used antipsychotics on metabolic outcomes.

The obesity risk gene FTO influences body mass in chronic schizophrenia but not initial antipsychotic drug-induced weight gain in first-episode patients

Genetic factors contribute to the individual variability in weight gain caused by several antipsychotic drugs. The FTO gene is associated with obesity in the general population; we have investigated whether a common risk polymorphism (rs9939609) in this gene is associated with antipsychotic drug-induced weight gain and obesity. Two samples were studied: (1) 93 first-episode patients receiving antipsychotic drugs for the first time and having body weight monitored for up to 12 months; (2) 187 chronic patients with schizophrenia assessed for measures of obesity and metabolic dysfunction. No association of FTO genotype with weight gain was found in initially drug-naive patients. The chronically treated patients had a significant association of genotype with body mass index (BMI), reflected in associations with waist circumference, waist:hip ratio and the frequency of central obesity. These findings indicate that FTO genotype has a major effect on body weight determined by BMI in chronically treated patients with schizophrenia.

759C/T Variants of the Serotonin (5-HT2C) Receptor Gene and Weight Gain in Children and Adolescents in Long-Term Risperidone Treatment

BACKGROUND

Great inter-individual variability exists in the susceptibility to gain weight during antipsychotic treatment. Thus, we examined whether the -759C/T variants in the promoter region of the 5HT2C receptor gene were differentially associated with weight gain in children and adolescents in long-term risperidone treatment.

METHODS

Medically healthy 7 to 17 year-olds, treated with risperidone for ≥ six months, were enrolled. Anthropometric measurements, laboratory tests, and treatment history were obtained upon enrollment and from medical records. The effect of the genotype on the trajectory of age-sex-adjusted weight and body mass index (BMI) z scores before and after the onset of risperidone treatment was investigated.

RESULTS

In 124 subjects (90% males, mean age: 11.8 years) treated with risperidone for a mean of 2.8 years, weight and BMI z scores significantly increased after starting risperidone. This change was similar across the two genotype groups as were changes in several cardiometabolic variables.

CONCLUSION

In contrast to other reports, the T allele failed to confer protection against excessive weight gain or cardiometabolic abnormalities in this group of children and adolescents chronically treated with risperidone.

The role of hypothalamic H1 receptor antagonism in antipsychotic-induced weight gain

Treatment with second generation antipsychotics (SGAs), notably olanzapine and clozapine, causes severe obesity side effects. Antagonism of histamine H1 receptors has been identified as a main cause of SGA-induced obesity, but the molecular mechanisms associated with this antagonism in different stages of SGA-induced weight gain remain unclear. This review aims to explore the potential role of hypothalamic histamine H1 receptors in different stages of SGA-induced weight gain/obesity and the molecular pathways related to SGA-induced antagonism of these receptors. Initial data have demonstrated the importance of hypothalamic H1 receptors in both short- and long-term SGA-induced obesity. Blocking hypothalamic H1 receptors by SGAs activates AMP-activated protein kinase (AMPK), a well-known feeding regulator. During short-term treatment, hypothalamic H1 receptor antagonism by SGAs may activate the AMPK-carnitine palmitoyltransferase 1 signaling to rapidly increase caloric intake and result in weight gain. During long-term SGA treatment, hypothalamic H1 receptor antagonism can reduce thermogenesis, possibly by inhibiting the sympathetic outflows to the brainstem rostral raphe pallidus and rostral ventrolateral medulla, therefore decreasing brown adipose tissue thermogenesis. Additionally, blocking of hypothalamic H1 receptors by SGAs may also contribute to fat accumulation by decreasing lipolysis but increasing lipogenesis in white adipose tissue. In summary, antagonism of hypothalamic H1 receptors by SGAs may time-dependently affect the hypothalamus-brainstem circuits to cause weight gain by stimulating appetite and fat accumulation but reducing energy expenditure. The H1 receptor and its downstream signaling molecules could be valuable targets for the design of new compounds for treating SGA-induced weight gain/obesity.

Antipsychotic drugs opposite to metabolic risk: neurotransmitters, neurohormonal and pharmacogenetic mechanisms underlying with weight gain and metabolic syndrome

Important sources of metabolic diseases such as obesity and metabolic syndrome are significantly more prevalent in patients treated with antipsychotic drugs than the general population and they not only reduce the quality of life but also significantly reduce the life expectancy, being important risk factors for cardiovascular disease. The pathogenic mechanisms underlying these events are not entirely clear they are complex and multi-determined or not tied to a single defining event. In this review we examine the literature on the interactions of antipsychotic drugs with neurotransmitters in the brain, with pharmacogenetics hormones and peripheral mechanisms that may induce, albeit in different ways between different molecules, not only weight gain but also 'onset of major diseases such as diabetes, dyslipidemia and hypertension that are the basis of the metabolic syndrome. Today, the possible metabolic changes induced by various antipsychotic drugs and their major physical health consequences, are among the major concerns of clinicians and it is therefore necessary to monitor the main metabolic parameters to prevent or minimize any of these patients as well as the metabolism events associated with the use of antipsychotic drugs.

5-lipoxygenase-activating protein as a modulator of olanzapine-induced lipid accumulation in adipocyte

Experiments were performed in 3T3-L1 preadipocytes differentiated in vitro into adipocytes. Cells were treated with olanzapine and a 5-lipoxygenase (5-LOX) activating protein (FLAP) inhibitor MK-886. Lipid content was measured using an Oil Red O assay; 5-LOX and FLAP mRNA content was measured using quantitative real-time PCR; the corresponding protein contents were measured using quantitative Western blot assay. Olanzapine did not affect the cell content of 5-LOX mRNA and protein; it decreased FLAP mRNA and protein content at day five but not 24 hours after olanzapine addition. In the absence of MK-886, low concentrations of olanzapine increased lipid content only slightly, whereas a 56% increase was induced by 50 μM olanzapine. A 5-day cotreatment with 10 μM MK-886 potentiated the lipid increasing action of low concentrations of olanzapine. In contrast, in the presence of 50 μM olanzapine nanomolar and low micromolar concentrations of MK-886 reduced lipid content. These data suggest that FLAP system in adipocytes is affected by olanzapine and that it may modify how these cells respond to the second-generation antipsychotic drugs (SGADs). Clinical studies could evaluate whether the FLAP/5-LOX system could play a role in setting a variable individual susceptibility to the metabolic side effects of SGADs.

Drug-induced hypo- and hyperprolactinemia: mechanisms, clinical and therapeutic consequences

INTRODUCTION

The altered profiles of prolactin secretion in the anterior hypophysis, generated by pathological, pharmacological or toxicological causes, have special consequences on multiple functions in both genders.

AREAS COVERED

This selective review presents the main mechanisms controlling prolactin secretion, focusing on the interplay of various neurotransmitters or xenobiotics, but also on the role of psychic or posttraumatic stress. A detailed analysis of several pharmacotherapeutic groups with hyperprolactinemic effects emphasize on the relevance of the pharmacokinetic/pharmacodynamic mechanisms and the clinical significance of the long term administration.

EXPERT OPINION

Accurate monitoring and evaluation of the hyperprolactinemia induced by xenobiotics is strongly recommended. The typical antipsychotics and some of the atypical agents (amisulpride, risperidone, paliperidone), as well as some antidepressants, antihypertensives and prokinetics, are the most important groups inducing hyperprolactinemia. The hyperprolactinemic effects are correlated with their affinity for dopamine D2 receptors, their blood-brain barrier penetration and, implicitly, the requested dose for adequate occupancy of cerebral D2 receptors. Consequently, integration of available pharmacokinetic and pharmacodynamic data supports the idea of therapeutic switch to non-hyperprolactinemic agents (especially aripiprazole) or their association, for an optimal management of antipsychotic-induced hyperprolactinemia. Possible alternative strategies for counteracting the xenobiotics-induced hyperprolactinemia are also mentioned.

Reducing antipsychotic-induced weight gain in schizophrenia: a double-blind placebo-controlled study of reboxetine-betahistine combination

RATIONALE

Combination treatment with reboxetine, a selective norepinephrine reuptake inhibitor, and betahistine, a histamine H1 receptor agonist/H3 antagonist, was developed to produce complementary action in CNS pathways regulating appetite and body weight. In the present placebo-controlled study, we evaluated whether a reboxetine-betahistine combination attenuates olanzapine-induced weight gain in schizophrenia patients.

METHOD

Forty-three inpatients with DSM-IV schizophrenic disorder participated in a randomized double-blind study. Reboxetine (4 mg/day) with betahistine (48 mg/day) (N = 29) or placebo (N = 14) was co-administered with olanzapine (10 mg/day) for 6 weeks. Mental status was assessed at baseline and endpoint with relevant rating scales. Intention-to-treat method was used for statistical analysis.

RESULTS

Seven patients in the study group and four in the placebo group discontinued the trial. At the end of the trial, patients in the olanzapine/reboxetine + betahistine group gained significantly less weight than those in the olanzapine/placebo group [2.02 ± 2.37 and 4.77 ± 3.16 kg, respectively; t = 2. 89, degrees of freedom (df) = 41, p = 0.006]. The weight-attenuating effect of this combination was twofold larger than the weight-attenuating effect previously demonstrated with reboxetine alone. Significantly fewer patients in the study group than in the comparison group increased their initial weight by >7 %, the cutoff for clinically significant weight gain [3/29 (10.3 %) and 6/14 (42.9 %), respectively; χ (2) = 6.03, df = 1, p = 0.014]. The reboxetine-betahistine combination was safe and well tolerated.

CONCLUSIONS

Reboxetine-betahistine combination produces a clinically meaningful attenuation of olanzapine-induced weight gain. These results justify direct comparison between the reboxetine-betahistine combination and reboxetine alone.

Cell-free protein synthesis and purification of human dopamine D2 receptor long isoform

The human dopamine D2 receptor long isoform (D2L) has significant implications in neurological and neuropsychiatric disorders such as Parkinson's disease and schizophrenia. Detailed structural knowledge of this receptor is limited owing to its highly hydrophobic nature, which leads to protein aggregation and host toxicity when expressed in cellular systems. The newly emerging field of cell-free protein expression presents numerous advantages to overcome these challenges. This system utilizes protein synthesis machinery and exogenous DNA to synthesize functional proteins outside of intact cells. This study utilizes two different cell-free systems for the synthesis of human dopamine D2L receptor. These include the Escherichia coli lysate-based system and the wheat-germ lysate-based system. The bacterial cell-free method used pET 100/D-TOPO vector to synthesize hexa-histidine-tagged D2L receptor using a dialysis bag system; the resulting protein was purified using nickel-nitrilotriacetic acid affinity resin. The wheat germ system used pEU-glutathione-S-transferase (GST) vector to synthesize GST-tagged D2L receptor using a bilayer translation method; the resulting protein was purified using a GST affinity resin. The presence and binding capacity of the synthesized D2L receptor was confirmed by immunoblotting and radioligand competition assays, respectively. Additionally, in-gel protein sequencing via Nano LC-MS/MS was used to confirm protein synthesis via the wheat germ system. The results showed both systems to synthesize microgram quantities of the receptor. Improved expression of this highly challenging protein can improve research and understanding of the human dopamine D2L receptor.

The investigation of leptin and hypothalamic neuropeptides role in first attack psychotic male patients: olanzapine monotherapy

The mechanism underlying the weight gain due to treatment with olanzapine and other second generation antipsychotics has not been fully understood. To examine olanzapine's weight gain effects, we accepted first attack psychotic patients with no medication (pre-treatment) (n=22) and the healthy control group (n=26) in this study. After patientś diagnosis, they were hospitalized and then treated for four weeks with olanzapine (post-treatment). We used case-control association design to test body mass index (BMI) and biochemical changes in each group. We also investigated peripheral leptin and neuropeptides/hormones namely, pro-opiomelanocortin (POMC), cocaine and amphetaime regulated transcript (CART), and neuropeptide Y (NPY) levels. These neuropeptides which are synthesized/secreted from arcuate nucleus of hypothalamus affect food intake and therefore, body weight. After 4 weeks of olanzapine treatment; BMI (body mass index), waist circumference, blood triglyceride, total cholesterol, and very low density lipoprotein (VLDL) levels were increased significantly in patients compared to their pre-treatment baseline. In pre-treatment, patients' NPY levels were significantly lower while α-MSH, the anorexigenic product of POMC levels were significantly higher vs. control. Both leptin and NPY levels were significantly increased in patients after the treatment but the NPY levels were also significantly lower in post-treatment vs. the control group. The CART levels did not change after the treatment. We may presume that the antagonist effect of olanzapine on the serotonin (5HT2CR and 5HT1BR) receptors of the arcuate hypothalamic neurons may be a basis for a deregulation of the neurohormones secretion.

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.

Molecular and cellular analysis of human histamine receptor subtypes

The human histamine receptors hH(1)R and hH(2)R constitute important drug targets, and hH(3)R and hH(4)R have substantial potential in this area. Considering the species-specificity of pharmacology of H(x)R orthologs, it is important to analyze hH(x)Rs. Here, we summarize current knowledge of hH(x)Rs endogenously expressed in human cells and hH(x)Rs recombinantly expressed in mammalian and insect cells. We present the advantages and disadvantages of the various systems. We also discuss problems associated with the use of hH(x)R antibodies, an issue of general relevance for G-protein-coupled receptors (GPCRs). There is much greater overlap in activity of 'selective' ligands for other hH(x)Rs than the cognate receptor subtype than generally appreciated. Studies with native and recombinant systems support the concept of ligand-specific receptor conformations, encompassing agonists and antagonists. It is emerging that for characterization of hH(x)R ligands, one cannot rely on a single test system and a single parameter. Rather, multiple systems and parameters have to be studied. Although such studies are time-consuming and expensive, ultimately, they will increase drug safety and efficacy.

Gene-microRNA interactions associated with antipsychotic mechanisms and the metabolic side effects of olanzapine

RATIONALE

Changes in the cortical expression of small non-coding microRNA (miRNA) have been observed in postmortem analysis of psychotic disorders. Antipsychotic drugs (APDs) are the most effective treatment option for these disorders and have been associated with changes in gene expression. MicroRNA regulate numerous genes involved in brain development and function. It is therefore plausible to question whether miRNA expression is also altered and hence whether they take part in the neuroleptic mechanism of action.

OBJECTIVES

We sought to investigate whether treatment with APDs induces changes in miRNA expression and query the functional implications of such changes. Furthermore, we investigated the possible functional interplay of miRNA-gene regulatory interactions.

METHOD

High-throughput miRNA profiling of the whole brain of C57BL/6 mice treated with haloperidol, olanzapine or clozapine for 7 days was performed. Functional analysis was conducted on the putative targets of altered microRNA. Significant miRNA-gene regulatory interactions were evaluated by the integration of genome-wide mRNA expression analysis using the Bayesian networks with splitting-averaging strategy and functional analysis conducted.

RESULTS

Small subsets of miRNA were altered with each treatment with potential neurologically relevant influence. Metabolic pathways were enriched in olanzapine and clozapine treatments, possibly associated with their weight gain side effects. Neurologically and metabolically relevant miRNA-gene interaction networks were identified in the olanzapine treatment group.

CONCLUSION

This study is the first to suggest a role for miRNA in the mechanism of APD action and the metabolic side effects of the atypical ADPs, and adds support for their consideration in pharmacogenomics.

Antipsychotic-induced metabolic and cardiovascular side effects in schizophrenia: a novel mechanistic hypothesis

The use of antipsychotics is hindered by the frequent occurrence of metabolic and cardiovascular side effects, resulting in worsened quality of life and greater mortality as a result of cardiovascular and cerebrovascular disorders in schizophrenia patients than the comparable general population. The various antipsychotics induce extrapyramidal symptoms, impaired glucose and lipid metabolism, weight gain, hypertension and arrhythmias, with variable frequency. Second-generation antipsychotics appear to have several advantages over first-generation antipsychotics, including a claimed better action on cognitive function and the negative symptoms of schizophrenia, and lower frequency of extrapyramidal side effects; however, their use is associated with a greater frequency of metabolic and cardiovascular disturbances. The mechanisms of these important side effects are not well understood, and generic approaches (psychoeducational programmes and symptomatic therapies) have been proposed to limit their severity. Extensive data from the literature indicate that autonomic nervous system dysfunction--intrinsic to schizophrenia and strongly exacerbated by antipsychotic treatment--is the cause of the pervasive metabolic and vascular dysfunctions associated with schizophrenia. In this article, we marshal further literature data to argue that the metabolic and cardiovascular side effects of antipsychotics are primarily mediated by their ability to block peripheral dopamine receptors, which physiologically modulate sympathetic activity. We also propose that these effects might be overcome by providing peripheral dopaminergic stimulation.

Borderline personality disorder: current drug treatments and future prospects

Individuals with borderline personality disorder (BPD) suffer from marked affective disturbance, an unstable sense of self, difficulty in interpersonal relationships and heightened impulsivity, leading to high rates of self-harm and suicide. Patients are often refractory to treatment and are at high risk for acute or dangerous presentations, with a serious impact on mental health services. There has been much debate on the effectiveness of pharmacotherapy in treating different facets of the psychopathology of the disorder. Several guidelines recommend the use of antidepressant agents, mood stabilizers for affective dysregulation and impulsive-behavioural dyscontrol, and antipsychotics for cognitive-perceptual symptoms. However, concerns have recently been raised regarding the strength of evidence for these treatment recommendations in BPD. Here, we review the evidence for efficacy of the main psychotropic medications used in BPD, drawing, in particular, on evidence from randomized controlled trials and meta-analyses. Overall, meta-analysis provides little evidence to support the use of antidepressant medication in BPD outside episodes of major depression. However, there is evidence for the use of both mood stabilizers and antipsychotic medications for the treatment of specific aspects of the disorder. Most existing studies have been conducted on small numbers of patients, and there is a requirement for further large-scale trials to substantiate these findings. In addition, given the limitations of current pharmacological treatment of BPD, there is a pressing need to investigate potential new therapeutic targets, including neuropeptides, such as the opioids and vasopressin, and drugs targeted at ameliorating the biological effects of early life stress.

Are there different neural mechanisms responsible for three stages of weight gain development in anti-psychotic therapy: temporally based hypothesis

Weight gain as a result of atypical anti-psychotic treatment is a common issue with different atypical anti-psychotic treatments causing differing magnitudes of weight gain. Although differing amounts of weight gain result from different atypical agents little is known about the temporal course of weight gain in anti-psychotic treatment. Specifically is the time course of weight gain comparable across different agents. Therefore this article reviews the temporal course of weight gain for three common atypical anti-psychotics namely; clozapine, olanzapine and risperidone. It is evident that all three of these agents exhibit similar although at distinct magnitudes temporal courses of weight gain. That is an initial rapid increase from baseline to 3 months (stage 1), a steady increase from 3 months to 18 months (stage 2) and a plateau after this point (stage 3) with continued anti-psychotic treatment. It is postulated that each of these stages of weight gain result from distinct neural mechanisms. The hypothesized neural correlates for each stage of weight gain are reviewed and discussed. The article concludes with recommendations for future research.

Trajectories of agouti-related protein and leptin levels during antipsychotic-associated weight gain in patients with schizophrenia

OBJECTIVE

Some but not all second-generation antipsychotics can induce considerable weight gain and metabolic syndrome. Although the exact biochemical mechanisms for these adverse effects are unclear, appetite-regulating neuropeptides of the central nervous system are thought to be implicated in this process. The hypothalamic mediator Agouti-related protein (AGRP) is inhibited by leptin and was shown to increase food intake. The aim of the present study was to investigate the trajectory of AGRP levels during antipsychotic-induced weight gain.

METHODS

As part of a controlled prospective clinical study, we determined indicators of body fat mass, plasma AGRP, and leptin levels in 16 patients with schizophrenia treated with ziprasidone and 21 patients with schizophrenia treated with olanzapine. Measurements by enzyme-linked immunosorbent assay were obtained before treatment (T0), after 4 weeks (T1), and after 3 months (T2) of treatment.

RESULTS

Whereas body mass index and leptin levels increased in patients treated with olanzapine compared to patients treated with ziprasidone, plasma AGRP levels did not differ among the treatment groups and did not change over time. Associations between AGRP and fat mass as well as appetite were disrupted in the olanzapine-treated patients but not in the ziprasidone group.

CONCLUSION

Future studies are needed to test whether the lack of a decrease in AGRP levels during weight gain in patients treated with olanzapine could perpetuate adverse metabolic long-term effects.

Olanzapine and risperidone effects on appetite and ghrelin in chronic schizophrenic patients

Olanzapine and other second generation antipsychotics have been associated with weight gain, which may be related to changes in appetite and food intake. However, it is unclear whether changes in appetite in response to treatment with second generation antipsychotics are persistent in patients treated chronically with these medications and the extent to which changes in appetite are related to any continuing weight gain associated with long-term treatment with these drugs. In a randomized 5-month study of the effects of olanzapine and risperidone on metabolic changes in chronic schizophrenic patients, we assessed appetite changes using two scales and correlated appetite changes with weight gain and metabolic changes. There is evidence that the hormone ghrelin is related to appetite stimulation and falls during satiation after meals, and therefore, may be a physiological concomitant indicating appetite changes. We therefore, also measured ghrelin before and after a fatty meal at baseline and after 2 months of drug treatment. Neither olanzapine nor risperidone increased appetite during the 5 months of study drug treatment, and there was a trend for a decrease in appetite over time. Weight only increased slightly during treatment and changes in appetite scores were not correlated with changes in weight or changes in glucose or lipids. Fasting ghrelin did not increase in olanzapine- or risperidone-treated patients, and there were no significant changes in ghrelin responses to a fatty meal between baseline and 2 months of drug treatment, and no differences in response in olanzapine- vs. risperidone-treated patients. Our findings suggest that in chronic schizophrenic patients treated with multiple antipsychotics in the past, olanzapine or risperidone do not induce increases in appetite and appetite changes are not related to any further small drug-induced weight gain in these chronically treated patients. However, it is possible that different relationships may exist between appetite and weight changes induced by the medications in drug naive patients newly started on olanzapine or risperidone.

Aripiprazole partial agonism at 5-HT2C: a comparison of weight gain associated with aripiprazole adjunctive to antidepressants with high versus low serotonergic activities

OBJECTIVE

5-HT2C receptor antagonists are thought to contribute toward increased appetite and obesity. Aripiprazole acts as a partial agonist at the 5-HT2C receptor; hence, it is thought to cause little or no significant weight gain when used alone. We theorize that, in the presence of antidepressants with high serotonergic activity, aripiprazole acts as an antagonist at the 5-HT2C receptor, thus increasing the potential for weight gain. Conversely, in environments with low serotonergic activity, aripiprazole acts as an agonist at the 5-HT2C receptor, therefore having less potential for weight gain.

METHOD

A retrospective electronic medical record chart review of the Veterans Integrated Service Network 22 Veterans Affairs database was performed comparing patients' weight and body mass index (BMI) while taking aripiprazole alone (n = 1,177), versus aripiprazole plus a high-serotonergic antidepressant (citalopram, fluoxetine, paroxetine, sertraline, or venlafaxine) (n = 145), versus aripiprazole plus a low-serotonergic antidepressant (bupropion) (n = 77) for a minimum continuous duration of 6 months of aripiprazole monotherapy or combination treatment. The study was conducted from January 2010 through June 2011.

RESULTS

In our patient population, only the aripiprazole plus high-serotonergic antidepressants group had a statistically significant increase in weight (P = .0027) and BMI (P = .0016).

CONCLUSIONS

Our data suggest that, in the presence of antidepressants with high serotonergic activity, aripiprazole may act as an antagonist at the 5-HT2C receptor, resulting in weight gain. Conversely, when aripiprazole is used in the presence of antidepressants with low serotonergic activity, it may act as an agonist and result in little or no weight gain. This varying effect at the 5-HT2C receptor may explain why aripiprazole has not been associated with significant weight gain in previous studies focusing on schizophrenia and bipolar disorder.

Reducing olanzapine-induced weight gain side effect by using betahistine: a study in the rat model

Olanzapine is effective at treating multiple domains of schizophrenia symptoms. However, it induces serious metabolic side effects. Antipsychotic drug's antagonistic affinity to histamine H₁ receptors has been identified as a main contributor for weight gain/obesity side effects. This study therefore investigated whether a combined treatment of betahistine (a H₁ receptor agonist and H₃ receptor antagonist) could reduce the body weight/obesity induced by olanzapine. Female Sprague Dawley rats were treated orally with olanzapine (1 mg/kg, t.i.d.) and/or betahistine (2.67 mg/kg, t.i.d.), or vehicle for two weeks. Rats treated with olanzapine exhibited significant body weight gain and increased food intake. Co-treatment of olanzapine with betahistine significantly prevented (-45%) weight gain and reduced feeding efficiency compared to sole olanzapine treatment. Betahistine treatment alone had no effect on weight gain and food intake. Olanzapine reduced locomotor activity, but not betahistine. These findings demonstrate that olanzapine-induced body weight gain can partially be reduced by co-treatment with betahistine. Betahistine has H₃ receptor antagonistic effects to increase histamine release, which may augment its direct agonistic effects on H₁ receptors. These findings have important implications for clinical trials using betahistine to control antipsychotic-induced obesity side effects.

Body weight and metabolic adverse effects of asenapine, iloperidone, lurasidone and paliperidone in the treatment of schizophrenia and bipolar disorder: a systematic review and exploratory meta-analysis

BACKGROUND

The introduction of second-generation antipsychotics (SGAs) over the past 2 decades generated considerable optimism that better antipsychotic treatments for schizophrenia and bipolar disorder were possible. SGAs offer several tolerability benefits over first-generation antipsychotics (FGAs), particularly with respect to extrapyramidal symptoms. However, SGAs can induce serious metabolic dysregulations, especially in drug-naive, first-episode, and child and adolescent populations, with olanzapine and clozapine having the highest propensity to cause these abnormalities. In this context, newer SGAs were developed to further improve the adverse effect burden of available agents. However, until now, the metabolic risk profile of the newly approved SGAs - asenapine, iloperidone, lurasidone and paliperidone (paliperidone extended release and paliperidone palmitate) - has not been compared.

OBJECTIVE

The objective of this systematic review and exploratory meta-analysis was to assess the effects of asenapine, iloperidone, lurasidone and paliperidone on body weight and other metabolic parameters (cholesterol, triglycerides and glucose), as this information is relevant to guide clinical decision making.

METHOD

A systematic literature search (1966-March 2012), using the Cochrane Central Register of Controlled Trials and MEDLINE, CINAHL and EMBASE databases, was conducted for randomized, placebo-controlled and head-to-head clinical trials of asenapine, iloperidone, lurasidone and paliperidone. Published and unpublished data on changes in body weight and glucose and lipid metabolism parameters were extracted. For placebo-controlled, short-term (≤12 weeks) and longer-term (>12 weeks) trials with available data on ≥7% weight increase compared with pre-treatment weight, or mean weight change with standard deviation, a formal meta-analysis was performed, estimating the pooled effect size (represented as relative risk [RR], numbers-needed-to-harm [NNH] and weighted mean difference [WMD]). An exploratory meta-analysis was also performed for the other metabolic variables (cholesterol, triglycerides and glucose). Data from active- and placebo-controlled studies were used for a pooled comparison of simple mean changes in weight, cholesterol, triglyceride and glucose levels.

RESULTS

Fifty-six trials (n = 21 691) in schizophrenia (N = 49, n = 19 299) or bipolar disorder (N = 7, n = 2392) were identified (asenapine: N = 9, iloperidone: N = 11, lurasidone: N = 8, paliperidone: N = 28). Most of the trials (64.3%) were of ≤12 weeks' duration. In the short-term trials, compared with placebo, a ≥7% weight increase was statistically significantly (p < 0.05) most prevalent for asenapine (5 trials, n = 1360, RR = 4.09, 95% confidence interval [CI] 2.25, 7.43, NNH = 17), followed by iloperidone (4 trials, n = 1931, RR = 3.13, 95% CI 2.08, 4.70, NNH = 11) and paliperidone (12 trials, n = 4087, RR = 2.17, 95% CI 1.64, 2.86, NNH = 20). The effect of lurasidone on body weight (6 trials, n = 1793, RR = 1.42, 95% CI 0.87, 2.29) was not statistically significant. Short-term weight gain was statistically significantly (p < 0.001) greater than placebo with iloperidone (1 trial, n = 300, +2.50 kg, 95% CI 1.92, 3.08), paliperidone (15 trials, n = 3552, +1.24 kg, 95% CI 0.91, 1.57), asenapine (3 trials, n = 751, +1.16 kg, 95% CI 0.83, 1.49), as well as with lurasidone (5 trials, n = 999, +0.49 kg, 95% CI 0.17, 0.81, p < 0.01). Sufficient meta-analysable, longer-term, weight change data were only available for asenapine and paliperidone, showing statistically significantly (p < 0.001) greater weight gain versus placebo for both drugs (asenapine, 3 trials, n = 311, +1.30 kg, 95% CI 0.62, 1.98; paliperidone, 6 trials, n = 1174, +0.50 kg, 95% CI 0.22, 0.78). Although statistically significant, in general, no clinically meaningful differences were observed between the four newly approved SGAs and placebo regarding the mean change from baseline to endpoint in cholesterol levels in short-term trials, with the exception of iloperidone for total cholesterol (1 trial, n = 300, +11.60 mg/dL, 95% CI 4.98, 18.22, p ≤ 0.001), high-density cholesterol (1 trial, n = 300, +3.6 mg/dL, 95% CI 1.58, 5.62, p < 0.001) and low-density cholesterol (1 trial, n = 300, +10.30 mg/dL, 95% CI 4.94, 15.66, p < 0.001) and with the exception of lurasidone for high-density cholesterol (5 trials, n = 1004, +1.50 mg/dL, 95% CI 0.56, 2.44, p < 0.01). Asenapine increased total cholesterol statistically significantly (p < 0.05) during longer-term treatment (1 trial, n = 194, +6.53 mg/dL, 95% CI 1.17, 11.89). Regarding triglycerides, only short-term (3 trials, n = 1152, +1.78 mg/dL, 95% CI 0.40, 3.17, p < 0.01) and longer-term treatment with paliperidone (4 trials, n = 791, -0.20 mg/dL, 95% CI -0.40, -0.01, p < 0.05) had a statistically, but not clinically, significant effect. Statistically significant changes in glucose levels were noticed during short-term treatment with asenapine (2 trials, n = 379, -3.95 mg/dL, 95% CI -7.37, -0.53, p < 0.05) and iloperidone (1 trial, n = 300, +6.90 mg/dL, 95% CI 2.48, 11.32, p < 0.01), and during long-term treatment with paliperidone (6 trials, n = 1022, +3.39 mg/dL, 95% CI 0.42, 6.36, p < 0.05).

CONCLUSION

While preliminary data suggest the lowest weight gain potential with lurasidone and potentially relevant short-term metabolic effects for asenapine and iloperidone, data are still too sparse to comprehensively evaluate the metabolic safety of the newly approved SGAs. Therefore, there is a clear need for further controlled studies to evaluate whether these agents are less problematic regarding treatment-emergent weight gain and metabolic disturbances than other currently available antipsychotics.

Pharmacogenetic Aspects of Antipsychotic Drug-induced Weight Gain - A Critical Review

Treatment with several antipsychotic drugs can result in weight gain, which may lead to further morbidity such as type 2 diabetes and cardiovascular disease via the development of metabolic syndrome. These important and problematic metabolic consequences of antipsychotic drug treatment probably reflect a pharmacological disruption of the mechanisms involved in control of food intake and body weight. The extent of weight gain following antipsychotic drug treatment shows substantial variability between individuals, due in part to genetic factors. Common functional polymorphisms in many candidate genes implicated in the control of body weight and various aspects of energy and lipid metabolism have been investigated for association with weight gain in subjects receiving antipsychotic drug treatment, and with metabolic pathology in chronic schizophrenia. Perhaps the strongest and most replicated findings are the associations with promoter polymorphisms in the 5-HT2C receptor and leptin genes, although many other possible genetic risk factors, including polymorphisms in the fat mass and obesity associated (FTO) gene and genes for the alpha2A adrenoceptor and melanocortin4 receptor, have been reported. Genome-wide association studies (GWAS) have also addressed antipsychotic-induced weight gain and other indicators of metabolic disturbances. However there is as yet little consistency between these studies or between GWAS and classical candidate gene approaches. Identifying common genetic factors associated with drug-induced weight gain and its metabolic consequences may provide opportunities for personalized medicine in the predictive assessment of metabolic risk as well as indicating underlying physiological mechanisms.

Effect of atypical antipsychotics on fetal growth: is the placenta involved?

There is currently considerable uncertainty regarding prescribing practices for pregnant women with severe and persistent psychiatric disorders. The physician and the mother have to balance the risks of untreated psychiatric illness against the potential fetal toxicity associated with pharmacological exposure. This is especially true for women taking atypical antipsychotics. Although these drugs have limited evidence for teratological risk, there are reports of altered fetal growth, both increased and decreased, with maternal atypical antipsychotic use. These effects may be mediated through changes in the maternal metabolism which in turn impacts placental function. However, the presence of receptors targeted by atypical antipsychotics in cell lineages present in the placenta suggests that these drugs can also have direct effects on placental function and development. The signaling pathways involved in linking the effects of atypical antipsychotics to placental dysfunction, ultimately resulting in altered fetal growth, remain elusive. This paper focuses on some possible pathways which may link atypical antipsychotics to placental dysfunction.

Beyond dopamine: glutamate as a target for future antipsychotics

The dopamine hypothesis of schizophrenia remains the primary theoretical framework for the pharmacological treatment of the disorder. Despite various lines of evidence of dopaminergic abnormalities and reasonable efficacy of current antipsychotic medication, a significant proportion of patients show suboptimal treatment responses, poor tolerability, and a subsequent lack of treatment concordance. In recent decades, intriguing evidence for the critical involvement of other neurotransmitter systems in the pathophysiology of schizophrenia has emerged, most notably of dysfunctions within the glutamate pathways. Consequently, the glutamate synapse has arisen as a promising target for urgently needed novel antipsychotic compounds—particularly in regards to debilitating negative and cognitive symptoms poorly controlled by currently available drugs. In this paper, recent findings integrating glutamatergic and dopaminergic abnormalities in schizophrenia and their implications for novel pharmacological targets are discussed. An overview of compounds in various stages of development is given: drugs enhancing NMDA receptor function as well as metabotropic glutamate receptor (mGluR) agonist and positive allosteric modulators (PAMs) are emphasised. Together with other agents more indirectly affecting glutamatergic neurotransmission, their potential future role in the pharmacotherapy of schizophrenia is critically evaluated.

Novel olanzapine analogues presenting a reduced H1 receptor affinity and retained 5HT2A/D2 binding affinity ratio

Background

Olanzapine is an atypical antipsychotic drug with high clinical efficacy, but which can cause severe weight gain and metabolic disorders in treated patients. Blockade of the histamine 1 (H₁) receptors is believed to play a crucial role in olanzapine induced weight gain, whereas the therapeutic effects of this drug are mainly attributed to its favourable serotoninergic 2A and dopamine 2 (5HT_2A/D₂) receptor binding affinity ratios.

Results

We have synthesized novel olanzapine analogues 8a and 8b together with the already known derivative 8c and we have examined their respective in vitro affinities for the 5HT_2A, D₂, and H₁ receptors.

Conclusions

We suggest that thienobenzodiazepines 8b and 8c with lower binding affinity for the H₁ receptors, but similar 5HT_2A/D₂ receptor binding affinity ratios to those of olanzapine. These compounds may offer a better pharmacological profile than olanzapine for treating patients with schizophrenia.