The effect of clozapine on factors controlling glucose homeostasis

Elevated serum IGFBP-1 levels correlate with cognitive deficits in treatment-resistant and chronic medicated schizophrenia patients

BACKGROUND

Schizophrenia is a debilitating psychiatric disorder with diverse cognitive impairments. Insulin-like growth factor binding protein 1 (IGFBP-1), a ubiquitous negative regulator of IGF signaling, crosses the blood-brain barrier after peripheral synthesis. Given the crucial role of IGF signaling in cognitive function, we reasoned that altered serum IGFBP-1 concentrations might be associated with cognitive impairments in schizophrenia. To test this hypothesis, we examined the relationship between serum IGFBP-1 levels and cognitive performance in both medicated and treatment-resistant schizophrenia (TRS) patients.

METHODS

Serum IGFBP-1 was measured in 31 TRS patients, 49 chronic medicated schizophrenia (CMS) patients, and 53 healthy controls. Clinical symptom severity was evaluated using the Positive and Negative Syndrome Scale (PANSS) and cognitive functions using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).

RESULTS

Both TRS and CMS patients exhibited cognitive deficits compared to healthy controls (p < 0.05). Serum IGFBP-1 concentration differed significantly among groups (F=36.805, p < 0.001) and post hoc tests demonstrated significantly higher concentrations in both schizophrenia groups compared to controls (p < 0.001). Further, serum IGFBP-1 concentration was higher in the TRS group than the CMS group (p = 0.048). Correlation analysis identified a significant relationship between serum IGFBP-1 and attention in the TRS group (r = 0.411, p = 0.021), immediate memory in the CMS group (r = -0.417, p = 0.003), and RBANS total score in the CMS group (r = -0.368, p = 0.009). Multiple regression analysis adjusting for confounding factors revealed that serum IGFBP-1 was independently associated with attention in TRS patients (p = 0.016, 95 %CI. 0.002-0.015) and immediate memory in CMS patients (p = 0.022, 95 %CI-0.012 to -0.001).

CONCLUSIONS

Elevated serum IGFBP-1 concentration may serve as a predictive biomarker for distinct cognitive deficits in TRS and CMS patients. Further investigations are warranted.

Meta-analysis of peripheral insulin-like growth factor 1 levels in schizophrenia

OBJECTIVE

We aimed to investigate if there is a significant difference in peripheral insulin-like growth factor 1 (IGF-1) levels between schizophrenia patients and healthy controls and to determine whether a difference exists before and after initiation of antipsychotics.

METHODS

PubMed/MEDLINE, Scopus, and Web of Science were searched up to March 27, 2022. Original clinical studies of any type that reported peripheral blood, serum or plasma IGF-1 levels measured after fasting in schizophrenia patients and/or healthy control group were selected based on inclusion and exclusion criteria. Data were analyzed using Meta-Essentials: Workbooks for meta-analysis and pooled through random-effects meta-analyses.

RESULTS

Twelve publications met eligibility criteria. Schizophrenia patients under antipsychotic treatment had significantly lower peripheral IGF-1 levels compared to healthy controls (n = 632, Hedges' g -0.42, 95% CI from -0.79 to -0.04, p = .006, I2  = 70.38%), while no significant difference was found between schizophrenia patients regardless of the antipsychotic treatment status and healthy controls, as well as between antipsychotic naïve or free schizophrenia patients and healthy controls, and before and after initiation of antipsychotic treatment. However, high heterogeneity was observed and its potential sources in some of the subgroup analyses included sample type and region.

CONCLUSIONS

Schizophrenia patients under antipsychotic treatment seem to have lower peripheral IGF-1 levels compared to healthy controls. Additional studies with larger and more homogenous samples are needed to confirm these findings.

Insulin-like Growth Factor 2 (IGF-2) and Insulin-like Growth Factor Binding Protein 7 (IGFBP-7) Are Upregulated after Atypical Antipsychotics in Spanish Schizophrenia Patients

Insulin-like growth factor 2 (IGF-2) and IGF binding protein 7 (IGFBP-7) have been related to schizophrenia (SZ) due to their implication in neurodevelopment. The purpose of this study was to assess whether the alterations in IGF-2 and IGFBP-7 in SZ patients are intrinsically related to the psychiatric disorder itself or are a secondary phenomenon due to antipsychotic treatment. In order to test this hypothesis, we measured plasma IGF-2 and IGFBP-7 in drug-naïve first episode (FE) and multiple episodes or chronic (ME) SZ Caucasian patients who have been following treatment for years. A total of 55 SZ patients (FE = 15, ME = 40) and 45 healthy controls were recruited. The Positive and Negative Syndrome Scale (PANSS) and the Self-Assessment Anhedonia Scale (SAAS) were employed to check schizophrenic symptomatology and anhedonia, respectively. Plasma IGF-2 and IGFBP-7 levels were measured by Enzyme-Linked Immunosorbent Assay (ELISA). The FE SZ patients had much lower IGF-2, but not IGFBP-7, than controls. Moreover, both IGF-2 and IGFBP-7 significantly increased after atypical antipsychotic treatment (aripiprazole, olanzapine, or risperidone) in these patients. On the other hand, chronic patients showed higher levels of both proteins when compared to controls. Our study suggests that circulatory IGF-2 and IGFBP-7 increase after antipsychotic treatment, regardless of long-term conditions and being lower in drug-naïve FE patients.

A health promotion intervention to improve lifestyle choices and health outcomes in people with psychosis: a research programme including the IMPaCT RCT

Background

People with psychotic disorders have reduced life expectancy largely because of physical health problems, especially cardiovascular disease, that are complicated by the use of tobacco and cannabis.

Objectives

We set out to (1) chart lifestyle and substance use choices and the emergence of cardiometabolic risk from the earliest presentation with psychosis, (2) develop a pragmatic health promotion intervention integrated within the clinical teams to improve the lifestyle choices and health outcomes of people with psychosis and (3) evaluate the clinical effectiveness and cost-effectiveness of that health promotion intervention.

Design

We performed a longitudinal cohort study of people presenting with their first episode of psychosis in three mental health trusts and followed up participants for 1 year [work package 1, physical health and substance use measures in first episode of psychosis (PUMP)]. We used an iterative Delphi methodology to develop and refine a modular health promotion intervention, improving physical health and reducing substance use in psychosis (IMPaCT) therapy, which was to be delivered by the patient’s usual care co-ordinator and used motivational interviewing techniques and cognitive–behavioural therapy to improve health choices of people with psychosis (work package 2). We then conducted a multicentre, two-arm, parallel-cluster, randomised controlled trial to determine the clinical effectiveness and cost-effectiveness of using the intervention with people with established psychosis (work package 3: IMPaCT randomised controlled trial) in five UK mental health trusts. The work took place between 2008 and 2014.

Participants

All people aged between 16 and 65 years within 6 months of their first presentation with a non-organic psychosis and who were proficient in English were eligible for inclusion in the PUMP study. Participants in the work package 2 training development were staff selected from a range of settings, working with psychosis. Participants in the phase 3 Delphi consensus and manual development comprised three expert groups of (1) therapists/researchers recruited from the local and national community, (2) clinicians and (3) service users, each of whom took part in two iterative review and feedback sessions. For work package 3, IMPaCT randomised controlled trial, care co-ordinators in participating community mental health teams who were permanently employed and had a minimum of four eligible patients (i.e. aged between 18 and 65 years with a diagnosis of a psychotic disorder) on their caseload were eligible to participate. In studies 1 and 3, patient participants were ineligible if they were pregnant or had a major illness that would have had an impact on their metabolic status or if they had a significant learning disability. All participants were included in the study only after giving written confirmed consent.

Main outcome measures

Cardiometabolic risk markers, including rates of obesity and central obesity, and levels of glycated haemoglobin (HbA1c) and lipids, were the main outcomes in work package 1 (PUMP), with descriptive data presented on substance use. Our primary outcome measure for the IMPaCT randomised controlled trial was the physical or mental health component Short Form questionnaire-36 items quality-of-life scores at 12 months.

Results

Obesity rates rose from 18% at first presentation with psychosis to 24% by 1 year, but cardiometabolic risk was not associated with baseline lifestyle and substance use choices. Patterns of increase in the levels of HbA1c over the year following first presentation showed variation by ethnic group. We recruited 104 care co-ordinators, of whom 52 (with 213 patients) were randomised to deliver IMPaCT therapy and 52 (with 193 patients) were randomised to deliver treatment as usual, in keeping with our power calculations. Of these 406 participants with established psychosis, 318 (78%) and 301 (74%) participants, respectively, attended the 12- and 15-month follow-ups. We found no significant effect of IMPaCT therapy compared with treatment as usual on the physical or mental health component Short Form questionnaire-36 items scores at either time point in an intention-to-treat analysis [physical health score (‘d’) –0.17 at 12 months and –0.09 at 15 months; mental health score (‘d’) 0.03 at 12 months and –0.05 at 15 months] or on costs. Nor did we find an effect on other cardiovascular risk indicators, including diabetes, except in the case of high-density lipoprotein cholesterol, which showed a trend for greater benefit with IMPaCT therapy than with treatment as usual (treatment effect 0.085, 95% confidence interval 0.007 to 0.16; p = 0.034).

Limitations

Follow-up in work package 1 was challenging, with 127 out of 293 participants attending; however, there was no difference in cardiometabolic measures or demographic factors at baseline between those who attended for follow-up and those who did not. In work package 3, the IMPaCT randomised controlled trial, care co-ordinators struggled to provide additional time to their patients that was devoted to the health promotion intervention on top of their usual clinical care contact with them.

Conclusions

Cardiometabolic risk is prominent even soon after first presentation with psychosis and increases over time. Lifestyle choices and substance use habits at first presentation do not predict those who will be most cardiometabolically compromised 1 year later. Training and supervising care co-ordinators to deliver a health promotion intervention to their own patients on top of routine care is not effective in the NHS for improving quality of life or reducing cardiometabolic risk.

Future work

Further work is needed to develop and evaluate effective, cost-effective and affordable ways of preventing the emergence of and reversing existing cardiometabolic risk indicators in people with psychosis.

Trial registration

Current Controlled Trials ISRCTN58667926.

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 8, No. 1. See the NIHR Journals Library website for further project information.

Outcome of a psychosocial health promotion intervention aimed at improving physical health and reducing alcohol use in patients with schizophrenia and psychotic disorders (MINT)

BACKGROUND

Life expectancy is reduced by 19 years in men and 17 in women with psychosis in Sweden, largely due to cardiovascular disease.

AIM

Assess whether a psychosocial health promotion intervention improves cardiometabolic risk factors, quality of life, and severity of illness in patients with psychotic disorders more than treatment as usual.

METHODS

A pragmatic intervention trial testing a manual-based multi-component health promotion intervention targeting patients with psychosis. The Swedish intervention was adapted from IMPaCT therapy, a health-promotion program based on motivational interviewing and cognitive behavioral therapy, designed to be incorporated into routine care. The intervention group consisted of 119 patients and the control group of 570 patients from specialized psychosis departments. Outcome variables were assessed 6 months before intervention during the run-in period, again at the start of intervention, and 12 months after the intervention began. The control group received treatment as usual.

RESULTS

The intervention had no significant effect on any of the outcome variables. However, BMI, waist circumference, systolic BP, heart rate, HbA1c, general health, and Clinical Global Impressions Scale score improved significantly during the run-in period before the start of the active intervention (observer effect). The multi-component design meant that treatment effects could only be calculated for the intervention as a whole.

CONCLUSION

The results of the intervention are similar to those of the U.K. IMPaCT study, in which the modular health-promotion intervention had little effect on cardiovascular risk indicators. However, in the current study, the run-in period had a positive effect on cardiometabolic risk factors.

Clozapine-induced Insulin-resistant Hyperglycemia in a Diabetic Patient

Clozapine is superior to all other antipsychotics in treatment-resistant schizophrenia. However, metabolic side effects are common while treating patients with clozapine. Administering clozapine in a patient who already is diabetic involves careful weighing of risks and benefits. Here, we report our experience of starting clozapine in a known diabetic patient. Clozapine was started in a patient with treatment-resistant psychosis in view of suicidal risk. Her diabetes mellitus was under good control with oral medications. After initiation of clozapine, blood sugars increased several fold within few days. Blood glucose continued to increase even with high doses of insulin and insulin infusion. Finally, blood sugars came under control only after discontinuation of clozapine. Precautionary measures while initiating clozapine in a diabetic patient are suggested - close monitoring of blood sugar during the initial few days and intensive intervention if blood sugar levels increase. Discontinuation of clozapine should also be kept in mind as a last resort.

Cardiovascular risk factors and metabolic syndrome in people with established psychotic illnesses: baseline data from the IMPaCT randomized controlled trial

BACKGROUND

The aims of the study were to determine the prevalence of cardiometabolic risk factors and establish the proportion of people with psychosis meeting criteria for the metabolic syndrome (MetS). The study also aimed to identify the key lifestyle behaviours associated with increased risk of the MetS and to investigate whether the MetS is associated with illness severity and degree of functional impairment.

METHOD

Baseline data were collected as part of a large randomized controlled trial (IMPaCT RCT). The study took place within community mental health teams in five Mental Health NHS Trusts in urban and rural locations across England. A total of 450 randomly selected out-patients, aged 18-65 years, with an established psychotic illness were recruited. We ascertained the prevalence rates of cardiometabolic risk factors, illness severity and functional impairment and calculated rates of the MetS, using International Diabetes Federation (IDF) and National Cholesterol Education Program Third Adult Treatment Panel criteria.

RESULTS

High rates of cardiometabolic risk factors were found. Nearly all women and most men had waist circumference exceeding the IDF threshold for central obesity. Half the sample was obese (body mass index ≥ 30 kg/m2) and a fifth met the criteria for type 2 diabetes mellitus. Females were more likely to be obese than males (61% v. 42%, p < 0.001). Of the 308 patients with complete laboratory measures, 57% (n = 175) met the IDF criteria for the MetS.

CONCLUSIONS

In the UK, the prevalence of cardiometabolic risk factors in individuals with psychotic illnesses is much higher than that observed in national general population studies as well as in most international studies of patients with psychosis.

Blood levels of glucose and insulin and insulin resistance in patients with schizophrenia on clozapine monotherapy

OBJECTIVE

We tested the hypothesis that fasting blood glucose and insulin levels are higher in schizophrenic subjects on clozapine monotherapy compared with healthy controls and they correlate with anthropometric measurements, laboratory tests and body composition.

METHODS

Data for 24 subjects with schizophrenia treated with clozapine and 24 age- and sex-matched healthy volunteers was analyzed.

RESULTS

Patients taking clozapine had higher fasting levels of glucose (103.5±31.6 vs. 87.8±11.7mg/dL, z=-2.03, p=0.04), there was no difference for insulin concentrations and markers of insulin resistance. In the clozapine group glucose levels correlated with clozapine dose (R=-0.43, p=0.03), while insulin levels correlated with weight (R=0.66, p<0.001), body mass index (R=0.54, p=0.007), abdominal (R=0.53, p=0.007) and waist (R=0.43, p=0.04) circumference, total body fat (R=0.51, p=0.01), and uric acid levels (R=0.50, p=0.01). In the clozapine group insulin levels were lower in subjects with body mass index <25kg/m(2) (7.0±3.3 vs. 13.4±8.8μU/mL, p=0.04) and in subjects without abdominal obesity (6.3±2.4 vs. 13.3±8.6μU/mL, p=0.03).

CONCLUSIONS

We found higher blood glucose levels in subjects taking clozapine and no differences in blood insulin levels between subjects with schizophrenia and controls. Associations between blood insulin levels and abdominal/waist circumferences support the role of abdominal obesity as an important risk factor of insulin resistance.

The comparison of glycometabolism parameters and lipid profiles between drug-naïve, first-episode schizophrenia patients and healthy controls

To compare the difference in body mass index (BMI), waist-to-hip ratio (WHR), and glucose and lipid metabolism parameters between drug-naïve, first-episode schizophrenia patients and healthy controls matched for age, ethnicity and gender, we conducted a test including BMI, WHR, and fasting glucose and lipid metabolism parameters in both 70 drug-naïve, first-episode schizophrenia patients, having not a single day of cumulative exposure to antipsychotic medications and 44 normal healthy controls at baseline. Student's t tests (two tailed) were conducted to examine between group differences. We found that drug-naïve first-episode schizophrenia patients had higher insulin, insulin resistance and C-peptide levels, and had lower total cholesterol (TC), high density lipoprotein cholesterol (HDL-c) and apolipoproteinA1 levels. Simultaneously, drug-naïve, first-episode schizophrenia patients show a potential tendency of WHR enlargement, although there were no statistically significant differences between groups (mean=0.82, SD=0.06, for the patients versus mean=0.79, SD=0.06, for the health subjects). These results suggest that drug-naïve, first-episode schizophrenia patients do differ from healthy controls in their fasting glycometabolism parameters and lipid profiles, including fasting plasma levels of insulin, C-peptide, TC, HDL-c, and apolipoproteinA1, and patients are more insulin resistant before the onset of antipsychotic medication treatment.

Sex difference in effects of typical and atypical antipsychotics on glucose-insulin homeostasis and lipid metabolism in first-episode schizophrenia

OBJECTIVE

The present study was to investigate the sex difference in effects of clozapine, olanzapine, risperidone, and sulpiride on glucose and lipid metabolism in first-episode schizophrenia.

METHOD

One hundred twelve patients with schizophrenia were assigned randomly to receive clozapine, olanzapine, risperidone, or sulpiride for 8 weeks. Planned assessments included body mass index, waist-hip ratio, fasting glucose, insulin, C-peptide, insulin resistance index (IRI), cholesterol and triglyceride levels. All measures were collected at baseline and at the end of the 8-week treatment.

RESULTS

After treatment, waist-hip ratio and triglyceride and IRI levels of men were increased higher than that of women in clozapine and olanzapine groups. In sulpiride group, body mass index and triglyceride, insulin, and IRI levels of women increased higher than those of men. There was no significant sex difference for all assessments in risperidone group. Insulin, C-peptide, and IRI, but not fasting glucose levels, were significantly increased in the 4 groups. Cholesterol and triglyceride levels were significantly increased in the clozapine and olanzapine groups. Patients treated with clozapine and olanzapine had higher fasting insulin, C-peptide, and IRI levels than those treated with risperidone and sulpiride.

CONCLUSIONS

These results suggest that clozapine, olanzapine, and sulpiride had effects on glucose and lipid metabolism in first-episode schizophrenia with sex difference. Clozapine and olanzapine seem to have the greatest potential to induce glucose and lipid metabolism abnormalities, and risperidone has the least.

Insulin resistance is associated with hypercortisolemia in Polynesian patients treated with antipsychotic medication

OBJECTIVE

Type 2 diabetes is more prevalent in the indigenous Polynesian population of New Zealand (Maori) than in Europeans. The aim of this study was to determine whether insulin resistance in Maori psychiatric patients was associated with antipsychotic treatment and to investigate the mechanism of an association.

RESEARCH DESIGN AND METHODS

Thirty adult Maori psychiatric patients receiving antipsychotic medication for >6 months and 30 healthy, age-, sex-, and BMI-matched control subjects were enrolled. Early morning fasting blood samples were analyzed for plasma levels of glucose, insulin, A1C, triglycerides, total cholesterol, IGF-1, cortisol, cortisol-binding globulin (CBG), and adiponectin.

RESULTS

The patient group had significantly higher median fasting insulin plasma levels than the control group (P = 0.002), which were independent of BMI, age, and sex. In addition, the patient group had significantly higher total cortisol (P = 0.03) and lower CBG levels (P = 0.004) than the control group, resulting in significantly higher levels of free cortisol (P = 0.004). The patient group was also significantly more hypoglycemic (P = 0.026) and hypertriglyceridemic (P = 0.028) than the control group. There was no significant difference in BMI, waist circumference, A1C, total cholesterol, IGF-1, or adiponectin levels between the two groups.

CONCLUSIONS

An increase in insulin resistance is seen in Maori psychiatric patients treated with antipsychotic medication. Therefore, Polynesian ethnicity should be considered in prescribing practice and general care of this group. In addition, the hypothalamic-pituitary-adrenal axis may have an important role in the mechanism by which this insulin resistance develops.

Effects of typical and atypical antipsychotics on glucose-insulin homeostasis and lipid metabolism in first-episode schizophrenia

RATIONALE

Glucose and lipid metabolism dysfunction is a significant side effect associated with antipsychotics. Although there are many studies about the linkages between drugs and metabolic dysfunction, most of these studies have compared the effects of two antipsychotics on only one metabolic measure: either glucose or lipid metabolism.

OBJECTIVES

The present study aimed to investigate the effects of clozapine, olanzapine, risperidone, and sulpiride on glucose and lipid metabolism in first-episode schizophrenia.

MATERIALS AND METHODS

One hundred twelve schizophrenics were assigned randomly to receive clozapine, olanzapine, risperidone, or sulpiride for 8 weeks. Planned assessments included body mass index (BMI), waist-to-hip ratio, fasting glucose, insulin, C-peptide, insulin resistance index (IRI), cholesterol, and triglyceride. All measures were collected at baseline and at the end of the 8-week treatment.

RESULTS

After treatment, insulin, C-peptide, and IRI were significantly increased in the four groups, but not fasting glucose levels. Cholesterol and triglyceride levels were significantly increased in the clozapine and olanzapine groups. Patients treated with clozapine and olanzapine had higher fasting insulin, C-peptide, and IRI levels than those treated with risperidone and sulpiride. Among the four antipsychotics, the increases of mean BMI from high to low were as follows: clozapine, olanzapine, sulpiride, and risperidone.

CONCLUSIONS

This study confirmed that the four antipsychotic drugs were associated with an increase of insulin, C-peptide, and IRI. It was found that clozapine and olanzapine were associated with an increase in cholesterol and triglyceride levels. The effects of clozapine and olanzapine on the glucose and lipid metabolism outweighed those of risperidone and sulpiride.