Relationship between body mass index and insulin resistance in patients treated with second generation antipsychotic agents

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A review of real-world data on the effects of aripiprazole on weight and metabolic outcomes in adults

BACKGROUND

Metabolic abnormalities observed with atypical antipsychotic treatment may be specific to each antipsychotic medication. The association between atypical antipsychotics and risk factors for cardiovascular disease prompted the American Diabetes Association (ADA) and the American Psychiatric Association (APA) to issue a consensus statement that categorized aripiprazole and ziprasidone as atypical antipsychotics with a lower likelihood of metabolic abnormalities.

OBJECTIVE

The aim of the current systematic review was to evaluate real-world studies (i.e. observational/naturalistic and open-label studies) assessing the risk for weight gain, dyslipidemia, glucose abnormalities, and diabetes mellitus in adult patients receiving treatment with atypical antipsychotics, with a specific focus on aripiprazole.

METHODS

A systematic PubMed search for articles published between 1 January 2000 and 4 October 2011 was performed using the following search terms in the title and abstract: aripiprazole, atypical, glucose, insulin, cholesterol, triglycerides, diabetes, hemoglobin A1c, weight, body mass index, and hyperlipidemia.

RESULTS

Twenty-two peer-reviewed articles were found that assessed the metabolic effects associated with aripiprazole treatment, including studies from small observational trials to large databases (n = 15 to n > 1,700,000). Thirteen articles reported observational or naturalistic studies, and nine were open-label trials evaluating weight gain, dyslipidemia, glucose abnormalities, and the risk of developing diabetes in adult patients receiving treatment with aripiprazole. Compared with other atypical antipsychotics, aripiprazole was either less likely to have an impact or had a comparable impact on weight gain and dyslipidemia; the degree of effect appeared to be dependent on study design. In addition, there was less risk of diabetes mellitus with aripiprazole compared with most other atypical antipsychotic agents.

CONCLUSIONS

Consistent with data from randomized controlled studies, the current review of observational/naturalistic and open-label studies suggests aripiprazole may be associated with a lower risk than other commonly used atypical antipsychotics for metabolic adverse events in adults, consistent with the ADA/APA consensus statement.

Association of obesity and treated hypertension and diabetes with cognitive ability in bipolar disorder and schizophrenia

OBJECTIVES

People with bipolar disorder or schizophrenia are at greater risk for obesity and other cardio-metabolic risk factors, and several prior studies have linked these risk factors to poorer cognitive ability. In a large ethnically homogenous outpatient sample, we examined associations among variables related to obesity, treated hypertension and/or diabetes and cognitive abilities in these two patient populations.

METHODS

In a study cohort of outpatients with either bipolar disorder (n = 341) or schizophrenia (n = 417), we investigated the association of self-reported body mass index and current use of medications for hypertension or diabetes with performance on a comprehensive neurocognitive battery. We examined sociodemographic and clinical factors as potential covariates.

RESULTS

Patients with bipolar disorder were less likely to be overweight or obese than patients with schizophrenia, and also less likely to be prescribed medication for hypertension or diabetes. However, obesity and treated hypertension were associated with worse global cognitive ability in bipolar disorder (as well as with poorer performance on individual tests of processing speed, reasoning/problem-solving, and sustained attention), with no such relationships observed in schizophrenia. Obesity was not associated with symptom severity in either group.

CONCLUSIONS

Although less prevalent in bipolar disorder compared to schizophrenia, obesity was associated with substantially worse cognitive performance in bipolar disorder. This association was independent of symptom severity and not present in schizophrenia. Better understanding of the mechanisms and management of obesity may aid in efforts to preserve cognitive health in bipolar disorder.

Effects of antipsychotic medications on appetite, weight, and insulin resistance

Although clozapine, olanzapine, and other atypical antipsychotic drugs (APDs) have fewer extrapyramidal side effects, they have serious metabolic side effects such as substantial weight gain, intra-abdominal obesity, and type 2 diabetes mellitus. Given that most patients with mental disorders face chronic, even life-long, treatment with APDs, the risks of weight gain/obesity and other metabolic symptoms are major considerations for APD maintenance treatment. This review focuses on the effects of APDs on weight gain, appetite, insulin resistance, and glucose dysregulation, and the relevant underlying mechanisms that may be help to prevent and treat metabolic side effects caused by APD therapy.

Gender-dependent consequences of chronic olanzapine in the rat: effects on body weight, inflammatory, metabolic and microbiota parameters

RATIONALE

Atypical antipsychotic drugs (AAPDs) such as olanzapine have a serious side effect profile including weight gain and metabolic dysfunction, and a number of studies have suggested a role for gender in the susceptibility to these effects. In recent times, the gut microbiota has been recognised as a major contributor to the regulation of body weight and metabolism. Thus, we investigated the effects of olanzapine on body weight, behaviour, gut microbiota and inflammatory and metabolic markers in both male and female rats.

METHODS

Male and female rats received olanzapine (2 or 4 mg/kg/day) or vehicle for 3 weeks. Body weight, food and water intake were monitored daily. The faecal microbial content was assessed by 454 pyrosequencing. Plasma cytokines (tumour necrosis alpha, interleukin 8 (IL-8), interleuin-6 and interleukin 1-beta (IL-1β)) as well as expression of genes including sterol-regulatory element binding protein-1c and CD68 were analysed.

RESULTS

Olanzapine induced significant body weight gain in the female rats only. Only female rats treated with olanzapine (2 mg/kg) had elevated plasma levels of IL-8 and IL-1β, while both males and females had olanzapine-induced increases in adiposity and evidence of macrophage infiltration into adipose tissue. Furthermore, an altered microbiota profile was observed following olanzapine treatment in both genders.

CONCLUSIONS

This study furthers the theory that gender may impact on the nature of, and susceptibility to, certain side effects of antipsychotics. In addition, we demonstrate, what is to our knowledge the first time, an altered microbiota associated with chronic olanzapine treatment.

Pharmacogenetics of antipsychotic-induced weight gain: review and clinical implications

Second-generation antipsychotics (SGAs), such as risperidone, clozapine and olanzapine, are the most common drug treatments for schizophrenia. SGAs presented an advantage over first-generation antipsychotics (FGAs), particularly regarding avoidance of extrapyramidal symptoms. However, most SGAs, and to a lesser degree FGAs, are linked to substantial weight gain. This substantial weight gain is a leading factor in patient non-compliance and poses significant risk of diabetes, lipid abnormalities (that is, metabolic syndrome) and cardiovascular events including sudden death. The purpose of this article is to review the advances made in the field of pharmacogenetics of antipsychotic-induced weight gain (AIWG). We included all published association studies in AIWG from December 2006 to date using the Medline and ISI web of knowledge databases. There has been considerable progress reaffirming previous findings and discovery of novel genetic factors. The HTR2C and leptin genes are among the most promising, and new evidence suggests that the DRD2, TNF, SNAP-25 and MC4R genes are also prominent risk factors. Further promising findings have been reported in novel susceptibility genes, such as CNR1, MDR1, ADRA1A and INSIG2. More research is required before genetically informed, personalized medicine can be applied to antipsychotic treatment; nevertheless, inroads have been made towards assessing genetic liability and plausible clinical application.

Metabolic consequences of antipsychotic therapy: preclinical and clinical perspectives on diabetes, diabetic ketoacidosis, and obesity

Antipsychotic drugs, particularly second-generation antipsychotics (SGAs), have reduced the burden to society of schizophrenia, but many still produce excessive weight gain. A significant number of SGAs also act directly to impair glycemic control causing insulin resistance, impaired glucose tolerance and type 2 diabetes, and also rarely diabetic ketoacidosis (DKA). Schizophrenia itself is almost certainly causal in many endocrine and metabolic disturbances, making this population especially vulnerable to the adverse metabolic consequences of treatment with SGAs. Hence, there is an urgent need for a new generation of antipsychotic drugs that provide efficacy equal to the best of the SGAs without their liability to cause weight gain or type 2 diabetes. In the absence of such safe and effective alternatives to the SGAs, there is a substantial clinical need for the introduction of new antipsychotics without adverse metabolic effects and new antiobesity drugs to combat these metabolic side effects. We discuss the adverse metabolic consequences of schizophrenia, its exacerbation by a lack of social care, and the additional burden placed on patients by their medication. A critical evaluation of the animal models of antipsychotic-induced metabolic disturbances is provided with observations on their strengths and limitations. Finally, we discuss novel antipsychotic drugs with a lower propensity to increase metabolic risk and adjunctive medications to mitigate the adverse metabolic actions of the current generation of antipsychotics.

Actigraphic monitoring of activity and rest in schizophrenic patients treated with olanzapine or risperidone

Metabolic disturbances are a growing concern for the treatment of schizophrenia. As decreased activity and poor sleep quality are risk factors for metabolic disturbances, we investigated the activity and sleep patterns of schizophrenic patients using actigraphy. Seventy-three patients with schizophrenia spectrum disorder (mean age 29.2 ± 10.2 years, 27 females) treated with olanzapine (n = 54) or risperidone (n = 19) and 36 age- and sex-matched healthy controls were examined. Actigraphic recordings were obtained throughout seven consecutive days. The Athens Insomnia Scale (AIS) and Epworth Sleepiness Scale (ESS) were used to assess sleep and daytime sleepiness. Drug side effects were evaluated with the Udvalg for Kliniske Undersogelser (UKU) Side Effect Rating Scale and Barnes Akathisia Rating Scale (BARS). Mental status was rated with the Positive and Negative Syndrome Scale (PANSS) and Calgary Depression Scale for Schizophrenia (CDSS). The patients had lower mean 24 h-activity (p < 0.001) and mean 10 h-daytime-activity (p < 0.001), and longer time in bed (p < 0.001). Higher PANSS scores, especially in the negative symptoms scale, were related to lower activity (r(s) = -0.508, p < 0.001). Higher depressive symptoms were related to lower mean 24 h-activity (r(s) = -0.233, p = 0.049), longer time in bed (r(s) = 0.315, p = 0.007) and higher AIS (r(s) = 0.377, p = 0.001) and ESS scores (r(s) = 0.321, p = 0.006). Healthy females presented higher activity than healthy males (p < 0.001). Similar but not significant gender differences were observed in the patients. These findings show that patients with schizophrenia treated with olanzapine or risperidone exhibit low physical activity and altered sleep pattern which may promote metabolic side effects. These changes are linked to negative and depressive symptoms.

Gender differences in antipsychotic prescribing

OBJECTIVE

Optimum outcome for those with psychosis will necessarily involve treatment with antipsychotic medication. Unfortunately this medication is associated with a high rate of adverse effects and as a consequence non-adherence. Maximizing symptomatic relief whilst minimizing side effects is the aim of treatment. In order to do this adequately prescribers need to be aware of the significant differences between men and women in response to antipsychotic treatment. These differences are not simply biologically mediated; both physiological and sociocultural factors contribute.

METHOD

Findings from a variety of sources were used to summarize gender differences in antipsychotic treatment.

RESULTS

Pharmacokinetic and pharmacodynamic factors, the impact of reproductive phases in women and gender differences in antipsychotic prescription across the lifespan (from children and adolescents to the elderly) are discussed. Important ethnic and racial differences are also mentioned.

CONCLUSION

Women require less antipsychotic medication than men to achieve a better symptom response, but this is at the expense of a higher side effect burden, in particular hormonal and metabolic side effects. Children, adolescents and the elderly are at especially high risk of adverse reactions with antipsychotics. In order to optimize outcome in people with psychosis, prescribers should ensure that gender differences are taken into account.

Relationship between insulin resistance and C-reactive protein in a patient population treated with second generation antipsychotic medications

C-reactive protein (CRP) is an inflammatory marker associated with obesity, insulin resistance, and cardiovascular disease. A recent study found CRP levels to be higher in individuals treated with certain antipsychotic medications such as olanzapine; however, it is not clear whether this is associated directly with drug intake or indirectly with drug-associated weight gain and insulin resistance. The objective of this study was to explore the potential predictors of CRP including insulin resistance, components of the metabolic syndrome, psychiatric diagnosis, and antipsychotic medication in patients treated with antipsychotics. Sixty-four outpatients without diabetes being treated with a single second generation antipsychotic medication had direct measurements of insulin resistance at the end of a 180-min infusion of glucose, insulin, and octreotide (insulin suppression test) as well as components of the metabolic syndrome. Insulin resistance was the strongest predictor of CRP (r=0.52, P<0.001). When adjusted for insulin resistance, there was no significant relationship between CRP and any of the components of the metabolic syndrome criteria, specific drug treatment or psychiatric diagnoses. In conclusion, insulin resistance is strongly associated with CRP levels and likely contributes to earlier associations between CRP and certain antipsychotic treatments.

Bone remodeling, bone mass and weight gain in patients with stabilized schizophrenia in real-life conditions treated with long-acting injectable risperidone

BACKGROUND

Prolactin-raising antipsychotics, risperidone (antidopaminergic activity), may be associated with low bone mass. On the other hand, risperidone may cause an increase in body weight thought to be favorable for bone.

OBJECTIVES

(1) To determine bone remodeling parameters and bone mass in patients with schizophrenia on long-term treatment with long-acting injectable risperidone (LAIR) in naturalistic settings, and (2) to evaluate the change in body weight, metabolic profile and neuroendocrine status in these patients.

DESIGN

This was a prospective, cross-sectional study.

PATIENTS

Patients included 26 outpatients with controlled schizophrenia in real-life conditions (age 31.3 ± 1.3 years, BMI 28.1 ± 1.0) on long-term maintenance therapy with LAIR for a mean of 18.0 ± 1.6 months (range 6-36) with a mean dose of 38 ± 2 mg. 35 subjects matched for sex, age, BMI and education served as healthy controls.

METHODS

Serum osteocalcin, C-terminal telopeptide of type I collagen (CTx), vitamin D, leptin, prolactin, sex steroids, and parathyroid hormone were assessed. Indices of insulin sensitivity and resistance were determined following an oral glucose tolerance test (OGTT). Bone mineral density (BMD) was measured by dual X-ray absorptiometry at the lumbar spine (LS) and femoral neck (FN).

RESULTS

Mild to moderate hyperprolactinemia (1,000-2,000 mU/l) was associated with asymptomatic hypogonadism. Prolactin values >2,000 mU/l occurred in a few female patients. Hypogonadism leads to a slight increase (upper limit of normal) in bone resorption marker (CTx) in patients with schizophrenia (p = 0.023). As for bone mass, although lower at the spine than in healthy subjects, it did not reach statistical significance (p = 0.094), while at the FN, BMD was not different from healthy subjects. Body weight increased on average 8.7 ± 1.6 kg in more than 50% of patients. Leptin levels adjusted for BMI in females were significantly higher in patients than in healthy female subjects (p = 0.018), while in males there was no difference between the groups (p = 0.833). A high prevalence of low vitamin D levels and more current smokers were found in patients with schizophrenia. As for the metabolic profile during treatment with risperidone, the low Matsuda index of insulin sensitivity (p = 0.039) confirmed insulin resistance in these patients.

CONCLUSION

A potential long-term consequence of asymptomatic hypogonadism due to risperidone-induced hyperprolactinemia might cause a slight rise in bone resorption marker (CTx). On the other hand, by increasing body weight, risperidone could have a protective effect on the bone and thus no change in bone mass was recorded when compared with healthy controls.