Assessment of risk of venous thromboembolism and its possible prevention in psychiatric patients

Letter to the FDA Proposing Major Changes in the US Clozapine Package Insert Supported by Clozapine Experts Worldwide. Part II: A Review of Fatal Outcomes in US Pharmacovigilance Data and Proposed Changes

PURPOSE/BACKGROUND

This is the second part of a 2-part article that proposes improving the United States (US) clozapine package insert. Part II focuses on fatal outcomes and the 5 boxed warnings, 4 specifically for clozapine: severe neutropenia, seizure, orthostatic hypotension and myocarditis, and 1 for all antipsychotics (elderly with dementia).

METHODS

US reports to the World Health Organization's global pharmacovigilance database were analyzed from clozapine's introduction to January 15, 2023.

FINDINGS/RESULTS

The US was the top reporter worldwide for clozapine with 56,003 reports and 9587 associated fatal outcomes. The 4 clozapine boxed warnings were associated with 534 fatal outcomes (218 with severe neutropenia, 131 with seizures, 125 with orthostasis, 36 with myocarditis, 24 with cardiomyopathy, and 0 with mitral valve prolapse). With no boxed warnings, pneumonia was associated with 674 fatal outcomes and increased white blood cell count (a sign of infection) with 596 fatal outcomes. After considering overlaps, pneumonia and increases in white blood cell count explained 900 fatalities, or 9.4% of 9587 fatal outcomes. The Food and Drug Administration continues to focus on severe neutropenia which was associated with only 218 or 2.3% of fatal outcomes, whereas 97.7% of fatal outcomes reported in US clozapine-treated patients had another cause.

IMPLICATIONS/CONCLUSIONS

To help prevent future deaths in clozapine-treated patients, the clozapine package insert should focus on fatal outcomes during infections. Part II offers detailed solutions regarding current boxed warnings and lack of a warning for pneumonia and other infections. The Supplementary Material includes letters of support from 124 non-US clozapine experts from 44 countries/regions who support Parts I and II.

Association between antipsychotics and pulmonary embolism: a pharmacovigilance analysis

BACKGROUND

Previous studies have documented an increased risk of pulmonary embolism (PE) in patients with schizophrenia taking antipsychotics (APs). However, specific data from real-world studies remain limited. This study aims to investigate the potential relationship between APs and PE.

RESEARCH DESIGN AND METHODS

In the Food and Drug Administration Adverse Event Reporting System (FAERS), from the first quarter of 2018 to the first quarter of 2023, all PE cases suspected of being induced by APs were collected for disproportionality analysis, and the reporting odds ratio (ROR) was used to evaluate associations. Mortality, life-threatening events, and hospitalizations were also analyzed for each APs.

RESULTS

A total of 1,676 cases of PE related to APs were included. APs were significantly associated with PE (ROR 2.00, 1.91-2.10), including chlorpromazine (n = 41), haloperidol (n = 164), loxapine (n = 37), olanzapine (n = 461), paliperidone (n = 161), quetiapine (n = 526), risperidone (n = 274), aripiprazole (n = 254), and clozapine (n = 234). The median onset time of PE was 29 days. Among all cases, 347 (20.7%) resulted in death, with haloperidol (53.2%) having a higher mortality rate than other APs.

CONCLUSIONS

APs may increase the risk of PE in patients with schizophrenia.

Revealing the reporting disparity: VigiBase highlights underreporting of clozapine in other Western European countries compared to the UK

BACKGROUND

Pharmacovigilance studies indicate clozapine history is marked by adverse drug reactions (ADRs).

OBJECTIVE

In a 2021 article, the United Kingdom (UK) had >90 % of European clozapine-related fatal outcomes in VigiBase, the World Health Organization's pharmacovigilance database. Two possibly opposing hypotheses could explain this disparity: 1) fewer reported fatal outcomes in other Western European countries mainly reflect underreporting to VigiBase, and 2) the higher number of UK reports reflects higher real relative mortality.

METHODS

VigiBase reports from clozapine's introduction to December 31, 2022, were studied for ADRs and the top 10 causes of fatal outcomes. The UK was compared with 11 other top reporting Western countries (Germany, Denmark, France, Finland, Ireland, Italy, Netherlands, Norway, Spain, Sweden and Switzerland). Nine countries (except Ireland and Switzerland) were compared after controlling for population and clozapine prescriptions.

RESULTS

The UK accounted for 29 % of worldwide clozapine-related fatal outcomes, Germany 2 % and <1 % in each of the other countries. The nonspecific label "death" was the top cause in the world (46 %) and in the UK (33 %). "Pneumonia" was second in the world (8 %), the UK (12 %), Ireland (8 %) and Finland (14 %). Assuming that our corrections for population and clozapine use are correct, other countries underreported only 1-10 % of the UK clozapine fatal outcome number.

CONCLUSIONS

Different Western European countries consistently underreport to VigiBase compared to the UK, but have different reporting/publishing styles for clozapine-related ADRs/fatal outcomes. Three Scandinavian registries suggest lives are saved as clozapine use increases, but this cannot be studied in pharmacovigilance databases.

Clinical Characteristics of Asymptomatic Thromboembolism in Psychiatric Inpatients: A Retrospective Study

Purpose

Venous thromboembolism (VTE) poses a significant threat to individuals' health, yet its correlation with mental disorders remains underappreciated. Here, we conducted a retrospective analysis to explore the characteristics of psychiatric patients presenting with VTE.

Methods

We retrospectively analyzed psychiatric inpatients with elevated plasma D-dimer levels at the Mental Health Center, First Affiliated Hospital, Zhejiang University School of Medicine, from January 2014 to January 2022. The inclusion criteria comprised comprehensive demographic and clinical profiles, including laboratory and imaging findings.

Results

A cohort of 33 eligible patients was included, with plasma D-dimer levels ranging from 880 to 10,700 μg/L FEU. Significantly higher D-dimer levels were observed in patients diagnosed with severe mental disorders (SMD), such as schizophrenia and bipolar disorder, compared to those with mild mental disorders (MMD), including depression and anxiety disorders (p = 0.007). Furthermore, individuals receiving antipsychotic medications for less than one year exhibited elevated D-dimer levels compared to those on treatment for over one year (p = 0.005). However, normalization of D-dimer levels did not demonstrate a significant association with psychiatric diagnosis or treatment duration (p > 0.05).

Conclusion

Our findings suggest that patients diagnosed with SMD or those undergoing antipsychotic treatment for less than one year may have elevated D-dimer levels, indicating a potential predisposition to VTE severity. This underscores the importance of recognizing VTE risk in individuals with severe mental disorders and warrants further investigation into the impact of antipsychotic treatment duration on thrombotic risk.

Fatal pulmonary embolism in patients on antipsychotics: case series, systematic review and meta-analysis

Since the 1950 s, several studies have reported that patients using first generation and/or second-generation antipsychotics had increased risk of venous thromboembolism events. These events include deep vein thrombosis and/or pulmonary embolism (PE). However, data about fatal PE in patients on antipsychotics (APs) remain scarce. Thus, the current study aimed to investigate sociodemographic, clinical and pharmacological characteristics related to psychiatric patients on APs and who died from a fatal PE. We reported a case-series, then conducted a literature review of relevant studies and performed a meta-analysis of studies with usable data. The main outcome of the study suggested a significantly high risk of fatal PE in patients using APs compared to nonusers (Odds Ratio=6.68, with 95% confidence interval 1.43-31.11). Clozapine was the most incriminated drug. Low potency first generation APs were the second most exhibited medication. Studies about the topic remain scarce with a high heterogeneity and a high probability of bias. Further studies are needed to ascertain this risk and to establish target preventive measures in this particularly vulnerable population.

Psychological and Psychopharmacological Interventions in Psychocardiology

Patients with mental disorders have an increased risk to develop cardiovascular disease (CVD), and CVD are frequently comorbid with especially adjustment, anxiety and depressive disorders. Therefore, clinicians need to be aware of effective and safe psychological and pharmacological treatment strategies for patients with comorbid CVD and mental disorders. Cognitive behavioral therapy and third-wave of cognitive-behavioral therapy are effective for patients with CVD and mental disorders. Internet-based psychological treatments may also be considered. In more severe cases, psychopharmacological drugs are frequently used. Although generally well tolerated and efficacious, drug- and dose-dependent side effects require consideration. Among antidepressants, selective serotonin reuptake inhibitors, selective serotonin and noradrenalin reuptake inhibitors, and newer antidepressants, such as mirtazapine, bupropion, agomelatine, and vortioxetine, can be considered, while tricyclic antidepressants should be avoided due to their cardiac side effects. Mood stabilizers have been associated with arrhythmias, and some first- and second-generation antipsychotics can increase QTc and metabolic side effects, although substantial differences exist between drugs. Benzodiazepines are generally safe in patients with CVD when administered short-term, and may mitigate symptoms of acute coronary syndrome. Laboratory and ECG monitoring is always recommended in psychopharmacological drug-treated patients with CVD. Presence of a heart disease should not exclude patients from necessary interventions, but may require careful risk-benefit evaluations. Effectively and safely addressing mental disorders in patients with CVD helps to improve both conditions. Since CVD increase the risk for mental disorders and vice versa, care providers need to screen for these common comorbidities to comprehensively address the patients' needs.

Venous thromboembolism in antiphosholipid syndrome

Antiphosholipid syndrome (APS) is defined by the presence of clinical and laboratory criteria, it means by presence of antiphospholipid antibodies. Venous thromboembolism belongs to the most frequent clinical manifestation of this syndrome. Here we summarised basic pathophysiological mechanisms of venous thrombosis and lung embolism development, epidemiology of APS, and also the situations when this syndrome should be considered. The possible difficulties of laboratory diagnosis and their therapy involvement are mentioned.

The Association and Influencing Factors between Antipsychotics Exposure and the Risk of VTE and PE: A Systematic Review and Meta-analysis

BACKGROUND

Different clinical studies have given inconsistent results on whether the use of antipsychotics increases the risk of thromboembolism. In this paper, we reviewed all relevant literature to provide suggestions for clinical diagnosis and treatment.

METHODS

PubMed, Web of Science, EMBASE, MEDLINE, Cochrane and Scopus databases were thoroughly searched up to June 2019. Two researchers independently searched the literature, extracted data. Data were analyzed by Stata 12.0 software.

RESULTS

A total of 22 studies involving 31514226 subjects were included. This meta-analysis showed that patients taking the first- or second-generation antipsychotics had a higher risk of venous thromboembolism and pulmonary embolism than those who did not, and low potency first-generation agents increased the risk of venous thromboembolism more than high potency antipsychotics, and olanzapine, clozapine, haloperidol, perphenazine and risperidone also significantly increased the risk of it. The risk of venous thrombosis in obese people was higher than that in overweight people, patients not less than 65 years old had an increased risk compared with younger patients. In addition, women taking antipsychotics had a higher risk of pulmonary embolism than men.

CONCLUSION

The use of antipsychotics will increase the risk of venous thromboembolism and pulmonary embolism, which will be affected by the type of antipsychotics and patient characteristics.

Clozapine-induced pulmonary embolism in a patient with minimal pre-existing risk factors

OBJECTIVES

Although the risk of antipsychotic-induced venous thromboembolism (VTE) has been definitively established, guidelines recommending prophylactic anticoagulation do not yet exist. Several algorithms have been proposed that suggest possible prophylaxis with an anticoagulant medication on the basis of pre-existing VTE risk factors. We present a case of antipsychotic-induced VTE despite the patient's low-risk status so that practitioners may better understand which factors may or may not constitute a major risk in this population when making a determination about prophylactic anticoagulation.

CASE SUMMARY

We present a patient case of a 56-year-old man with schizoaffective disorder who was treated with clozapine at an inpatient psychiatric unit. Although he would be classified as low risk for VTE on the basis of the proposed algorithms, he experienced a pulmonary embolism by day 17 of treatment and required transfer to a medical unit. This patient displayed sensitivity to other adverse effects associated with clozapine during his treatment course, including tachycardia, sialorrhea, enuresis, and bowel obstruction.

PRACTICE IMPLICATIONS

Many of the known risk factors for antipsychotic-induced VTE were not present in this patient, including immobility, hyperprolactinemia, and coagulation abnormalities. The recent initiation of clozapine and obesity seem to be the only identified risk factors, although malignancy and abnormal antiphospholipid antibody levels were not able to be ruled out. It is difficult to determine if this patient experienced a VTE owing to a relatively high degree of sensitivity to clozapine, as evidenced by the myriad of other adverse effects that he experienced. This case highlights the need to determine true antipsychotic-induced VTE risk factors, including evaluation of comorbid adverse effects that occur in addition to the VTE. This information will help to guide future decision-making regarding the risk versus benefit of providing prophylactic anticoagulation for patients during initiation of antipsychotic treatment.

Venous Thromboembolism as an Adverse Effect During Treatment With Olanzapine: A Case Series

Objective: Venous thromboembolism (VTE) is a serious multifactorial disorder. Patients with severe mental illness have a higher risk of developing the condition compared to the general population. Methods: We observed 10 cases of VTE in patients with mental illness who were treated with the antipsychotic drug olanzapine. The diagnosis of VTE was made at the University Hospital Hradec Kralove (UH HK) from 2004 to 2013. VTE was objectively determined by imaging techniques (duplex ultrasonography, CT angiography) and laboratory tests (D-dimer). The average age was 46 years. The clinical manifestation of VTE was deep vein thrombosis in nine cases, including one case of simultaneous pulmonary embolism and one case of a concurrent ischemic cerebrovascular accident (iCVA). None of our patients had a history of malignant disease, trauma, or surgery. Results: Apart from antipsychotic medication, all the patients had clinical or laboratory risk factors for VTE. The most frequent clinical risk factors were obesity (n = 7) and smoking (n = 6). The most frequent laboratory risk factors were increased levels of FVIII (n = 4), mild hyperhomocysteinemia (n = 3), and factor V Leiden mutation (n = 2). VTE developed within 3 months after antipsychotic drug initiation in three patients and within 6 months in three patients. Conclusion: Olanzapine can be considered a precipitating factor for VTE formation. When olanzapine is administered, we need to monitor for clinical signs and symptoms of VTE, especially when other risk factors are present.

[Catatonic melancoly and venous thromboembolism: A risky combination]

Catatonia is defined as a psychiatric syndrome. This syndrome is strongly associated with venous thromboembolism. As a difficult diagnosis in these patients, psychiatrists and vascular physicians should be aware of this association. We report here a clinical case of this association and discuss the diagnosis difficulties and therapeutics options.

Management of Violence and Aggression in Emergency Environment; a Narrative Review of 200 Related Articles

CONTEXT

The aim of this study is to reviewing various approaches for dealing with agitated patients in emergency department (ED) including of chemical and physical restraint methods.

EVIDENCE ACQUISITION

This review was conducted by searching "Violence," "Aggression," and "workplace violence" keywords in these databases: PubMed, Scopus, EmBase, ScienceDirect, Cochrane Database, and Google Scholar. In addition to using keywords for finding the papers, the related article capability was used to find more papers. From the found papers, published papers from 2005 to 2018 were chosen to enter the paper pool for further review.

RESULTS

Ultimately, 200 papers were used in this paper to conduct a comprehensive review regarding violence management in ED. The results were categorized as prevention, verbal methods, pharmacological interventions and physical restraint.

CONCLUSION

In this study various methods of chemical and physical restraint methods were reviewed so an emergency medicine physician be aware of various available choices in different clinical situations for agitated patients.

Direct and indirect effects of psychopharmacological treatment on the cardiovascular system

Background Severe mental disorders, i.e. psychotic disorders, unipolar and bipolar disorders are associated with increased morbidity and mortality from cardiovascular and metabolic disorders. The underlying cause of this association is complex and comprises disorder specific alterations such as dysfunctions of immunological and hormonal systems, body-composition changes and health associated behaviors (smoking, sedentary lifestyle, alcohol intake and treatment compliance). Furthermore, some psychopharmacological drugs may exert unwanted side effects that impact the cardiovascular system. Methods This paper reviews studies concerning commonly used antidepressant and antipsychotics drugs with a particular focus on direct and indirect cardiovascular side effects. Results Newer antidepressant drugs have a favorable cardiovascular safety profile compared to tricyclic antidepressants. However, QTc prolongation, increased blood pressure and potentially higher risks of bleeding have been observed in some newer antidepressants. Some second generation (atypical) antipsychotics have raised concern because of indirect cardiovascular, metabolic side effects such as weight gain and disturbances in lipid and glucose metabolism. Conclusions Psychiatrists need to be aware of potential direct and indirect cardiovascular side effects and to include them in the risk/benefit assessment when choosing a specific individualized treatment.

Thromboembolic risk after lumbar spine surgery: a cohort study on 325 000 French patients

Essentials The risk of venous thromboembolism (VTE) after lumbar spine surgery (LBS) is not precisely known. More than 320 000 patients who underwent LBS in France between 2009 and 2014 were followed-up. The overall risk of VTE after LBS is less than 1% but modulated by patient and procedural factors. Surgical device implantation, anterior approach and complex surgery increase the risk of VTE. SUMMARY: Background Postoperative venous thromboembolism (VTE) is a severe complication, the risk of which after lumbar spine surgery (LBS) is not precisely known. Objective To estimate the incidence of VTE after LBS, and to identify individual and surgical risk factors. Methods All patients aged >18 years who underwent LBS in France between 2009 and 2014 were identified. Among 477 024 patients screened, exclusions concerned recent VTE or surgery, and multiple surgeries during the same hospital stay. Results In 323 737 patients (mean age 52.9 years, 51.4% male), we observed 2911 events (0.91%) after a median time of 12 days (Q1-Q3: 5-72 days). The multivariate adjusted Cox model showed increased risks associated with age (4% per year of age; 95% confidence interval [CI] 3.8-4.3), obesity (hazard ratio [HR] 1.32, 95% CI 1.18-1.46), active cancer (HR 1.65, 95% CI 1.5-1.82), previous thromboembolism (HR 5.41, 95% CI 4.74-6.17), severe paralysis (HR 1.47, 95% CI 1.17-1.84), renal disease (HR 1.28, 95% CI 1.04-1.6), psychiatric disease (HR 1.21, 95% CI 1.1-1.32), use of antidepressants (HR 1.13, 95% CI 1.03-1.24), use of contraceptives (HR 1.56, 95% CI 1.19-2.03), extended surgery for scoliosis (HR 3.61, 95% CI 2.96-4.4), implantation of pedicular screws with a 'dose-effect' association, and an anterior approach (HR 1.97, 95% CI 1.6-2.43) or a combined approach (HR 2.03, 95% CI 1.44-2.84). Conclusions The overall VTE risk after LBS is moderate (< 1%) but is widely modulated by several easily identifiable risk factors. The surgical community should be aware of this heterogeneity, adapt prevention according to patients and to the procedure, and use drug prophylaxis in the event of a high risk being present.

Venous thromboembolism following initiation of atypical antipsychotics in two geriatric patients

Background

Although not formally highlighted as a risk factor in current practice guidelines, several observational studies have reported a possible association between antipsychotic use and development of venous thromboembolism (VTE). However, it is unclear to what extent the risk is elevated.

Case Report

Described are 2 cases of VTE following recent initiation of second-generation antipsychotics in elderly patients. Ms A was a 65-year-old woman with newly diagnosed bipolar I disorder who was hospitalized for acute mania and psychosis. She was treated with risperidone along with traditional mood stabilizers and developed a pulmonary embolism shortly after treatment initiation. Ms B was a 77-year-old woman with newly diagnosed bipolar I disorder who was hospitalized for depression and psychosis. She was treated with quetiapine and electroconvulsive therapy and developed a pulmonary embolism and deep vein thrombosis within 2 months of starting treatment. Risk assessment tools were not able to definitively predict the VTEs that developed in our patients.

Conclusion

The association between antipsychotic medication and VTE has shown the highest risk with atypical antipsychotics, high dosages, and initiation within the past 3 months. Risk assessment tools may assist in assessing the risk of VTE in patients on antipsychotic therapy, although patients who are deemed by these tools to have minimal risk can still develop a VTE. Discussing VTE risk with patients when considering antipsychotic usage may help clinicians and patients safely determine the most appropriate treatment for their psychiatric illnesses while mitigating potential adverse effects.

Different doses of folic acid and vitamin B12 to treat rabbits with deep venous thrombosis and hyperhomocysteinemia

The effects of different doses of folic acid and vitamin B12 on rabbits with deep vein thrombosis (DVT) and hyperhomocysteinemia were investigated. In total, 60 New Zealand rabbits were divided into untreated control, low-dose and high-dose groups. After inducing DVT, hemorheology and coagulation indexes were measured 3 and 10 days later. We found that both treatment groups performed better than the control group, and the high-dose performed better than the low-dose. Ten days after thrombosis, the levels of Hcy and D-dimer were lower in the high-dose group. Moreover, the changes of lower extremity deep venous thrombosis were significantly reduced in both high- and low-dose groups, but the high-dose group showed the most improvement. The effective rate of the high-dose group was 100%, higher than the rate in the low-dose and control groups. Overall, high-dose of folic acid and vitamin B12 can significantly improve plasma Hcy, coagulation indexes, and pathological changes in the venous thrombosis of the lower extremity.

Venous Thromboembolism During Treatment with Antipsychotics: A Review of Current Evidence

This article summarises the current evidence on the risk of venous thromboembolism (VTE) with the use of antipsychotics. An increasing number of observational studies indicate an elevated risk of VTE in antipsychotic drug users. Although the use of certain antipsychotics has been associated with VTE, current data can neither conclusively verify differences in occurrence rates of VTE between first- and second-generation antipsychotics or between individual compounds, nor identify which antipsychotic drugs have the lowest risk of VTE. The biological mechanisms involved in the pathogenesis of this adverse drug reaction are still to be clarified but hypotheses such as drug-induced sedation, obesity, increased levels of antiphospholipid antibodies, enhanced platelet aggregation, hyperhomocysteinaemia and hyperprolactinaemia have been suggested. Risk factors associated with the underlying psychiatric disorder may at least partly explain the increased risk. Physicians should be aware of this potentially serious and even sometimes fatal adverse drug reaction and should consider discontinuing or switching the antipsychotic treatment in patients experiencing a VTE. Even though supporting evidence is limited, prophylactic antithrombotic treatment should be considered in risk situations for VTE.

Incidence of venous thromboembolism in psychiatric inpatients: a chart review

PURPOSE

Venous thromboembolism (VTE) is the combination of pulmonary embolism (PE) and deep vein thrombosis. In recent years, VTE has been gaining attention in the field of psychiatry as it can cause sudden deaths in patients hospitalized in psychiatric departments. The purpose of this study was to investigate the incidence of VTE in psychiatric inpatients using contrast-enhanced computed tomography (CT).

PATIENTS AND METHODS

At the psychiatric department of the Akita University Hospital, NANOPIA^® D-dimer was measured in patients with suspected symptomatic VTE or believed to be at risk for asymptomatic VTE. A follow-up contrast-enhanced CT was also performed in cases of D-dimer values over 1 µg/mL. Patients diagnosed with VTE based on contrast-enhanced CT during hospitalizations between May 1, 2009 and April 30, 2017 were analyzed. VTE incidence was compared in restrained and unrestrained catatonic and noncatatonic patients. We also investigated whether VTE was symptomatic or asymptomatic as well as its outcomes.

RESULTS

The overall incidence of VTE was 2.3% (39/1,681) in the 8-year period. VTE was observed in 61.1% (11/18) of catatonic patients, 4.1% (11/270) of noncatatonic restrained patients, and 1.2% (17/1,393) of noncatatonic unrestrained patients. PE was observed in 76.9% (30/39) of VTE patients and 97.4% (38/39) of VTE patients were asymptomatic. Recovery was achieved in all cases of VTE treated with anticoagulation therapy.

CONCLUSION

These results indicate that the risk of VTE is high in psychiatric inpatients and that PE is common in these population. The data may also suggest that contrast-enhanced CT is important in surveying thrombus in suspected cases of VTE. In the psychiatric field, proper attention must be given to VTE, regardless of the presence or absence of catatonia or restraint, particularly given that PE was observed in more than 75% of cases of VTE.

The impact of antipsychotics as a risk factor for thromboembolism

Patients with schizophrenia are predisposed toward developing cardiovascular disease. Although neuroleptics affect the cardiovascular system, it is also important to consider the consequences of the disease itself such as lower physical activity due to living on disability pension, inadequate nutrition, and/or nicotine addiction, being more common among patients with schizophrenia versus the general population. All these factors combined lead to an increased risk of death caused by cardiovascular conditions in schizophrenic patients. Individuals receiving typical antipsychotic drugs have been reported to have elevated concentrations of antiphospholipid antibodies, including anticoagulants and anticardiolipin antibodies. The presence of both antibodies is associated with an increased risk for thromboembolism. It is also likely that mental illness is accompanied by increased procoagulant activity. Patients with acute psychosis have been shown to have a statistically significant increase in the concentrations of D-dimer, P-selectin, and in the expression of platelet glycoprotein IIb/IIIa receptors. Learning about causes and mechanisms of venous thromboembolism could help to reduce or neutralize the adverse effects of antipsychotic treatment and facilitate the identification of appropriate markers necessary to monitor changes and provide preventive care against hazardous and potentially fatal complications such as deep venous thrombosis and pulmonary embolism. Before atypical neuroleptic treatment is administered to hospitalized patients, all possible risk factors for thromboembolism should be considered to allow the application of lower risk drugs. Also, other preventive measures should be taken into account, including hydration, compression stockings, regular exercise of lower extremities, and low-molecular-weight heparin injections.

Prophylaxis of venous thromboembolism in physically restrained psychiatric patients

OBJECTIVE

We analysed the rate of physical restraint in acute and chronic psychiatric patients and looked at the safety of waiving venous thromboembolic disease (VTE) prophylaxis in the case of restraining of less than 24 h.

METHODS

We did a retrospective analysis of all episodes of restraining in 2012 and 2013, diagnosis of restrained patients, time of restraining and use of low molecular weight heparin (LMWH) for prophylaxis of VTE associated with restraining.

RESULTS

Overall, 12 734 patients were hospitalised. The number of episodes of restraining was 1035 and involved 469 (7.4%) patients. Only 79 episodes of restraining lasted more than 24 h and affected only 36 (0.3%) individual patients. The most frequent psychiatric diagnoses were unstable borderline personality in 41 (52%) and schizophrenic or schizoaffective psychosis in 26 (33%) episodes. None of these prolonged restraints and none of the 956 episodes of restraining for less than 24 h were associated with clinical symptoms or signs of VTE that would have required additional diagnostic consequences.

CONCLUSION

The concept of waiving VTE prophylaxis within the first 24 h of restraining seems to be safe. On the other hand, LMWH sufficiently protected the small sample being restrained for more than 24 h.

Depression and risk of venous thromboembolism: a population-based retrospective cohort study

OBJECTIVE

This study investigated the relationship between depression and the risk of subsequent venous thromboembolism (VTE) development.

METHODS

We conducted a population-based retrospective cohort analysis by using data for the period of 2000 to 2011 from the Longitudinal Health Insurance Database 2000 of Taiwan. A depression cohort comprising 35,274 patients and a nondepression cohort comprising 70,548 patients matched according to sex, age, and index year with no history of VTE were evaluated. Cox proportional hazard regression analysis was used to assess the effects of depression and comorbidities, and the Kaplan-Meier method was applied to estimate the cumulative VTE incidence curves.

RESULTS

Compared with individuals without depression, depressed patients had a 1.38-fold greater risk (95% confidence interval = 1.09-1.73) of developing VTE. This risk was significantly higher in male and younger (≤49 years) patients. In addition, patients with comorbidities such as hypertension, diabetes, heart failure, and cancer had a higher risk of depression-associated VTE that was attenuated, although nonsignificantly, by antidepressant use.

CONCLUSIONS

The incidence of VTE in Taiwan is higher in depressed patients than in nondepressed patients. Moreover, men, people 49 years or younger, and patients with comorbidities have a significantly greater risk of VTE after depression.

Introduction of a Venous Thromboembolism Prophylaxis Protocol for Older Adult Psychiatric Patients

Hospital-Acquired venous thromboembolism (VTE) is a common cause of morbidity and mortality in older adults. In psychiatric patients these risks are increased due to multiple factors including poor mobility, restraint, catatonia, sedation, and conventional antipsychotic use. Diagnosis and treatment of psychiatric patients presenting with signs and symptoms of a VTE can be delayed due to a patient's communication difficulties, non-compliance, or attribution of symptoms to a psychosomatic cause. However, despite the increased risk, approved VTE prophylaxis protocols are infrequently used on Psychiatric wards. On one Older Adult Psychiatric Ward, two patients presented with VTE (a fatal pulmonary embolism and a symptomatic deep vein thrombosis) over a 6 month period demonstrating the necessity for prophylactic assessment. A baseline audit over 3 months showed that 63-83% of patients on the ward had received no assessment of VTE risk, on any given week, although this improved slightly following the critical incidents. A VTE prophylaxis protocol, based on NICE guidance for VTE risk assessment in Medical and Surgical patients, was developed with consideration given to additional Psychiatric risk factors. This took the form of a pro-forma with a tick-box design that included mobility assessment, VTE risk factors, bleeding risk factors, and guidance on prescribing decisions. This was implemented on an Older Adult Psychiatric ward and prophylaxis was provided to those meeting the threshold. Weekly audit of all pro-formas (including assessments completed within 48 hours of admission and prophylaxis prescription) was conducted after the pro-forma introduction from 1st February 2013 to 24th May 2013. Frequency of assessments increased after protocol implementation with between 36% and 85% of all patients being assessed for VTE risk post intervention. Fluctuations in numbers assessed may have related to ward pressures, staff changes, and practicalities of pro-forma use. After completion of the PDSA cycles the initiative was handed over to a specialist registrar for implementation across the other trust Older Adult Psychiatry wards, and further audit was planned to be conducted via junior doctors and established Quality Assurance systems. Discussion of integration of a condensed pro-forma into the trust electronic notes system is ongoing.

Venous thromboembolism prophylaxis in mental healthcare: do the benefits outweigh the risks?

Venous thromboembolism is an important cause of morbidity and mortality. In recent years, growing awareness has led to the development of strategies to prevent venous thromboembolism in individuals admitted to hospital who are deemed to be at high risk. However, there remains a considerable degree of uncertainty over whether these strategies are of overall benefit and there are few published studies on people who are admitted to psychiatric hospitals. In this editorial I review current clinical practice and areas of uncertainty with respect to venous thromboembolism prophylaxis and its implementation in mental healthcare settings.

Prophylactic use of heparin for deep vein thrombosis in restrained psychiatric patients: a chart review

OBJECTIVE

Physical restraint sometimes causes deep vein thrombosis (DVT) and pulmonary embolism. Although unfractionated heparin (UFH) is used for the prophylaxis of DVT, its effectiveness remained unknown for restrained patients.

METHOD

We conducted a chart review of restrained inpatients at Sakuragaoka Memorial Hospital in Japan. Restrained patients received subcutaneous injection of UFH 5000 IU bid from December 2008 to September 2010 [heparin (+) period] while UFH was not used from December 2010 to September 2012 [heparin (-) period]. A Doppler ultrasound scanning was performed to examine the presence of DVT. The incidence of DVT was compared between the two periods by chi-square test. A multiple logistic regression model was used to examine effects of demographic and clinical characteristics on the incidence of DVT.

RESULTS

No significant difference was found in the incidence of DVT between the heparin (+) and (-) periods [11.8% (11/93) vs. 11.1% (13/117)]. Sedation [odds ratio (OR) = 3.78], physical comorbidities (OR = 6.29) and a longer duration of restraint (OR = 1.22) were associated with the incidence of DVT.

CONCLUSION

The use of UFH was not associated with any reduction in the incidence of DVT in restrained psychiatric patients.

Electroconvulsive therapy and anticoagulation after pulmonary embolism: a case report

Introduction Electroconvulsive therapy (ECT) is considered the most effective treatment for catatonia regardless its underlying condition. The rigid fixed posture and immobility observed in catatonia may lead to several clinical complications, of which, pulmonary embolism (PE) is one of the most severe. The rapid improvement of the psychiatric condition in catatonia-related PE is essential, since immobility favors the occurrence of new thromboembolic events and further complications. In that scenario, ECT should be considered, based on a risk-benefit analysis, aiming at the faster resolution of the catatonia. Methods Case report and literature review. Results A 66-years-old woman admitted to the psychiatric ward with catatonia due to a depressive episode presented bilateral PE. Clinically stable, but still severely depressed after a trial of antidepressants, she was treated with ECT in the course of full anticoagulation with enoxaparin. After five ECT sessions, her mood was significantly better and she was walking and eating spontaneously. She did not present complications related either to PE or to anticoagulation. After the eighth ECT session, she evolved with hypomania, which was managed with oral medication adjustments. The patient was completely euthymic at discharge. Conclusion The case we presented provides further evidence to the anecdotal case reports on the safety of ECT in the course of concomitant full anticoagulant therapy after PE, and illustrates how, with the proper precautions, the benefits of ECT in such condition might outweigh its risks.

Awareness of venous thromboembolism in mental health services for older people

Venous thromboembolism (VTE) is an important safety issue in the inpatient mental health care of older people. In a survey of specialist mental health staff, knowledge of deep vein thrombosis was good. More variable awareness of the presentation and risk factors for pulmonary embolism indicates the need for training integrated into regular physical health care updates. Currently, failure to adequately screen and prevent venous thromboembolism (VTE) is estimated to cause between 25,000 and 32,000 potentially avoidable deaths annually in the United Kingdom. The authors aimed to assess the awareness of VTE in clinical staff working in Mental Health Services for Older People, Tees, Esk and Wear Valleys National Health Service Foundation Trust. A questionnaire was devised to assess knowledge of VTE symptoms, risk factors, prevention, and treatment in clinical staff working in Mental Health Service for Older Peoples' inpatient units. Forty-nine nurses, 12 consultant psychiatrists, and 11 clinical pharmacists responded. A significant proportion of staff had previous involvement in VTE treatment. Staff had significantly more limited knowledge of pulmonary embolism compared to deep vein thrombosis with areas for improvement in presentation, risk factors, and prevention. The study confirms a need for improved awareness among all clinical staff including nurses, pharmacists, and doctors, which can be met by including VTE awareness in First Response training, and encouraging use of the Department of Health VTE e-learning tool.

Acute manic episode is associated with an increased risk of lower limb edema

OBJECTIVE

Lower limb edema (LLE) was suggested to be associated with the use of psychotropic drugs among patients suffering from severe mental illnesses; however no direct mechanism was found. Therefore, we examined the association between the occurrence of LLE and acute untreated episode leading to hospitalization.

METHODS

A retrospective cross-sectional study was conducted using medical charts of 2529 patients admitted to Geha Mental Health Center between 2002 and 2012. Incident cases of LLE, demographic and clinical data were retrieved. Admission clinical status was modeled as three non-overlapping groups of patients: (i) Patients with a non-affective psychosis (NAP) episode (n = 1563), (ii) patients with a manic episode (n = 366), and (iii) patients with a depressive episode (n = 600). We performed a logistic regression analysis with LLE as the dependent variable controlling for the demographic and clinical variables that may be associated with LLE.

RESULTS

LLE was diagnosed in 3.8% (n = 95) of the study population. The rate of LLE was 3-fold higher (χ(2) = 51.9, df = 2, p<0.001) in patients admitted with a manic episode (n = 38; 10.4%) compared to patients admitted with a NAP episode (n = 41; 2.6%) and patients admitted with a depressive episode (n = 16; 2.7%). Manic episode was associated with an increased risk for LLE compared to depressive episode (OR 8.72, 95% CI: 3.53-21.52, p<0.001) or NAP episode (OR 3.96, 95% CI: 2.16-7.26, p<0.001) after controlling for relevant confounders.

CONCLUSION

Acute manic episode, leading to hospitalization, is associated with an increased risk of LLE, compared to NAP or depressive episode, suggesting causal relationship between mood and fluid imbalance. Yet, future prospective studies are needed to rule out the contribution of physical agitation and lithium treatment.

Venous thromboembolism in psychogeriatric in-patients--a study of risk assessment, incidence, and current prophylaxis prescribing

BACKGROUND

While venous thromboembolism (VTE) risk assessment and prophylaxis is well established for medical and surgical in-patients, there is a paucity of evidence, and therefore guidelines, in this area for psychogeriatric in-patients. We wished to determine VTE incidence, risk, and use of prophylaxis, in a psychogeriatric in-patient population.

METHODS

Retrospective audit of consecutive psychogeriatric patients aged 65 years and over admitted to Bankstown Hospital over a 3-year period, 2007-2009. Using an adapted VTE risk scoring system, patients were assigned as low, medium, or high VTE risk.

RESULTS

A total of 192 patients were included in the study. Mean age was 79.1 ± 7.0 years. Out of the total, 55.2% of patients had diagnosis of dementia, and 33.3% had depression. Overall, 81.8% (157/192) were assessed as low risk, and 18.2% (35/192) as medium risk. Also, 16.7% (32/192) received VTE prophylaxis. Four new VTE events occurred in medium-risk group, and one in low-risk group (p = 0.004). Overall VTE incidence was 10.5/10,000 patient-days, but 44.2 per 10,000 in medium-risk group. VTE risk score was predictive of VTE events - IRR 6.02 (95% Confidence Intervals (CI) = 1.76-20.7, p = 0.004) for every one-point increment in risk. Depression was associated with significantly higher VTE occurrence (6.3% in those with diagnosis vs. 0.8% without, p = 0.043).

CONCLUSION

Using a VTE risk scoring system adapted for psychogeriatric in-patients, those assessed to be at medium risk had a significantly increased rate of VTE. On this basis, we would recommend VTE prophylaxis be prescribed for psychogeriatric in-patients assessed to be at medium and high level of risk.

Association between antidepressants and venous thromboembolism in Taiwan

OBJECTIVE

To investigate the association between venous thromboembolism (VTE) and antidepressant use in an Asian population.

METHODS

The authors conducted a nested case-control study of 1888 patients with VTE and 11,222 matched controls enrolled in the National Health Insurance Research Database in Taiwan from 2001 to 2009. The antidepressant exposure status and potential confounding factors were measured and included in the analyses. Conditional logistic regressions were applied to determine the effect of antidepressant use on VTE.

RESULTS

We found a significant association of current antidepressant use with VTE in the total study sample (adjusted odds ratio [aOR], 1.59; 95% confidence interval (CI), 1.27-2.00). With regard to antidepressant classes and potency, we found that tricyclic antidepressants (aOR, 1.56; 95% CI, 1.11-2.18), serotonin 5-HT2A receptor blockers (aOR, 2.03; 95% CI, 1.27-3.24), and antidepressants with a low potency of serotonin reuptake inhibition (aOR, 1.57; 95% CI, 1.18-2.08) were associated with a significantly increased risk of VTE. When further stratifying by age, sex, and comorbid conditions, the VTE risk with antidepressant use was elevated among young and middle-aged adults, but not among the elderly. In addition, an elevated risk of VTE was observed in women and subjects without severe comorbid conditions, but not in men and subjects with severe comorbid conditions.

CONCLUSIONS

There was a small increase in VTE risk with antidepressant use. The prescription of antidepressant drugs should be cautious, and especially, should be based on clinical evaluations of benefits and risks. The underlying mechanisms of the interaction between antidepressants and VTE warrant further investigation.

Risk of venous thromboembolism during treatment with antipsychotic agents

The evidence to date on the relation between the risk of venous thromboembolic disease (VTE) and antipsychotic agents derives primarily from observational and case history studies. While an increased risk of VTE has been associated with first-generation low-potency antipsychotic agents, particularly clozapine, there appears to be a growing number of reports on the occurrence of this adverse reaction during the use of second-generation antipsychotics, such as risperidone and olanzapine. The highest risk of pathological blood clotting emerges during the first 3 months after initiation of treatment with the product. Potential etiopathogenetic factors leading to VTE during treatment with antipsychotic agents include sedation, obesity, elevation of antiphospholipid antibodies, increased platelet activation and aggregation, hyperhomocysteinemia, and hyperprolactinemia. Diagnoses of schizophrenia and/or bipolar affective disorder, as well as hospitalization or stress with sympathetic activation and elevation of catecholamine levels, have been reported as known prothrombogenic factors. The present article contains the new version of the guideline for the prevention of VTE in psychiatric patients with limited mobility. Further prospective studies are necessary to elucidate the biological mechanisms of the relations between antipsychotic agents and VTE.

Deep venous thrombosis and atypical antipsychotics: three cases report

Background

Deep venous Thrombosis is a serious, possible life threatening event which is often ignored in psychiatric Settings.

Purpose

In this paper three cases of deep venous Thrombosis (DVT) following the use of olanzapine and risperidone are presented.

Methods

The data of Three patients was collected from hospital records.

Results

The patients were in good general physical health and had no personal or familial history of DVT. The patients were not overweight (BMI < 25) but they suffered from DVT after initiating risperidone and olanzapine.

Conclusion

Risk of DVT exists in patients under treatment with atypical antipsychotics in spite of no pre existing risk factor.

Incidence of venous thromboembolism in psychiatric units

INTRODUCTION

Incidence and risk factors of venous thromboembolism (VTE) are well established in surgical and medical settings, but data in psychiatric units are lacking. The aim of this study was to estimate the incidence of VTE in hospitalized psychiatric patients, and to assess the risk factors for VTE in this specific population.

MATERIALS AND METHODS

All consecutive adult patients, admitted for a psychiatric disorder for at least seven days in psychiatric units were considered for inclusion. Patients were evaluated for signs and symptoms of VTE during hospitalization. At Day 10, all participants were interviewed and a systematic compression ultrasonography of the lower limbs was performed. Patients were followed-up until Day 90.

RESULTS

Among the 471 included patients, 449 were evaluable at Day 10, and 458 were followed-up until Day 90. Ten deep vein thromboses (DVT) were diagnosed by Day 10 leading to an incidence of VTE of 2.2% (95% CI, 1.1%-4.1%). Six additional symptomatic VTE occurred between Day 10 and Day 90, leading to a 3.5% incidence at Day 90 (95% CI, 2.0%-5.6%). The main factors associated with VTE were age, bed rest, and diagnosis of dementia. The incidence of VTE in patients aged 75 or over with a diagnosis of dementia reached 8.2% at Day 10 and 12.5% at Day 90.

CONCLUSIONS

The incidence of VTE in psychiatric units appeared low. However, in older patients, especially those with dementia, the incidence of VTE increased considerably. Further studies are needed to confirm these results.

Idiopathic pulmonary thromboembolism in the course of intensive psychiatric inpatient care: case report and treatment guidelines

Idiopathic thromboembolism can occur in psychiatric patients who have been inactive during a period of inpatient hospital treatment. These patients are usually treated with antipsychotic medication which has also been reported to increase risk for thromboembolic disease. Here the authors describe a patient with neither prior history of thromboembolism nor any medical risk factors for thromboembolic disease, who was admitted with an acute relapse of psychotic illness. During the course of her intensive psychiatric treatment, she had chest pain and CT-pulmonary arteriogram revealed bilateral lower lobe pulmonary embolism. She was anticoagulated and made a full medical recovery. Treatment with high dosages of typical and atypical antipsychotic medication and a lack of mobility related to intensive nursing care and sedation were likely risk factors in her development of pulmonary emboli.

Venous thromboembolism in recipients of antipsychotics: incidence, mechanisms and management

Since chlorpromazine was introduced to the market in the early 1950s, the use of antipsychotic drugs has been associated with venous thromboembolism (VTE) in a number of reports. During the last decade the evidence has been strengthened with large epidemiological studies. Whether all antipsychotics increase the risk for VTE or the risk is confined to certain drugs is still unclear. The aim of this article is to present an updated critical review focusing on the incidence, mechanisms and management of VTE in users of antipsychotics. After searching the databases PubMed and Scopus for relevant articles we identified 12 observational studies, all of which were published after the year 2000. In most of these studies an elevated risk of VTE was observed for antipsychotic drugs, with the highest risk for clozapine, olanzapine and low-potency first-generation antipsychotics. The risk seems to be correlated with dose. The elderly, who mainly use lower doses, do not show an increased risk of VTE to the same extent as younger subjects. The underlying biological mechanisms explaining the association between antipsychotic medication and VTE are to a large extent unknown. Several hypotheses have been proposed, such as body weight gain, sedation, enhanced platelet aggregation, increased levels of antiphospholipid antibodies, hyperprolactinaemia and hyperhomocysteinaemia. The risk of VTE in schizophrenia and other psychotic disorders may also be related to the underlying disease rather than the medication. Very limited evidence exists to guide how cases of VTE in subjects using antipsychotics should be handled. An attempt to compile an algorithm where the patients' individual risk of VTE is assessed and preventive clinical measures are suggested has been published recently. Strong consideration should be given to discontinuation of the offending antipsychotic drug in patients experiencing a VTE, and another antipsychotic drug with a presumably lower risk should be chosen if antipsychotic drug treatment is still indicated. It is essential that physicians and patients are aware that VTE may be an adverse drug reaction to the antipsychotic treatment so the condition is identified early and treated appropriately.

Extensive Deep Venous Thrombosis in a Patient with Neurolept Malignant Syndrome despite Being on Prophylaxis

The risk of venous thromboembolism (VTE) in patients with Neuroleptic malignant syndrome (NMS) and those on antipsychotic medications is well established. We present here a case whereby the patient had NMS and developed extensive deep venous thrombosis (DVT) despite being on standard DVT Prophylaxis. Our case illustrates that empiric intravenous heparin for the initial few days after the onset of NMS may be considered in those with high risk of VTE, as in such patients standard DVT prophylaxis may not be sufficient. To standardize as to which patients with NMS would be at the highest risk of VTE while on standard DVT prophylaxis, the role of a standardized scoring system and a double-blind randomized trial in the future would probably be beneficial.

Markers of thrombogenesis are activated in unmedicated patients with acute psychosis: a matched case control study

BACKGROUND

Antipsychotic treatment has been repeatedly found to be associated with an increased risk for venous thromboembolism in schizophrenia. The extent to which the propensity for venous thromboembolism is linked to antipsychotic medication alone or psychosis itself is unclear. The objective of this study was to determine whether markers of thrombogenesis are increased in psychotic patients who have not yet been treated with antipsychotic medication.

METHODS

We investigated the plasma levels of markers indicating activation of coagulation (D-dimers and Factor VIII) and platelets (soluble P-selectin, sP-selectin) in an antipsychotic-naive group of fourteen men and eleven women with acute psychosis (age 29.1 ± 8.3 years, body mass index 23.6 ± 4.7), and twenty-five healthy volunteers were matched for age, gender and body mass index.

RESULTS

D-dimers (median 0.38 versus 0.19 mg/l, mean 1.12 ± 2.38 versus 0.28 ± 0.3 mg/l; P = 0.003) and sP-selectin (median 204.1 versus 112.4 ng/ml, mean 209.9 ± 124 versus 124.1 ± 32; P = 0.0005) plasma levels were significantly increased in the group of patients with acute psychosis as compared with healthy volunteers. We found a trend (median 148% versus 110%, mean 160 ± 72.5 versus 123 ± 62.5; P = 0.062) of increased plasma levels of factor VIII in psychotic patients as compared with healthy volunteers.

CONCLUSIONS

The results suggest that at least a part of venous thromboembolic events in patients with acute psychosis may be induced by pathogenic mechanisms related to psychosis rather than by antipsychotic treatment. Finding an exact cause for venous thromboembolism in psychotic patients is necessary for its effective treatment and prevention.

The prevention of deep venous thrombosis in physically restrained patients with schizophrenia

BACKGROUND

Physical restraint and seclusion are associated with several risks. Antipsychotic drug use increases this risk.

OBJECTIVE

To evaluate whether the risk of thromboembolism in physical restraint and seclusion of patients with psychosis, treated with antipsychotic medication, was considered by taking preventive measures.

METHOD

Anonymous data on all consecutively admitted patients with schizophrenia, treated with antipsychotic medication, between 2002 and 2009, were analysed. Diagnostic information and data about seclusion procedures and medication were collected. Preventive measures of thromboembolism in patients in physical restraint were assessed by reviewing case notes and the medication prescribed at the time of seclusion.

RESULTS

Seclusion of patients with psychosis is common. Out of 679 identified patients, 170 had been secluded (472 events). Physical restraint use was not a rare event (N seclusions with restraint use 296, 62.7%). Pharmacological preventive measures (use of heparine drugs) were taken frequently to prevent deep vein thrombosis (DVT) by physical restraint or isolation. Sixty-five (38.2%) out of 170 secluded patients, including a majority of patients who had been under physical restraint, had been administered anticoagulants at the time of seclusion. No cases of DVT occurred.

CONCLUSIONS

Preventive measures were routinely administered in clinical practice and were effective in the prevention of DVT. For a clinical setting, it is important to establish a clear and detailed management plan on seclusion and fixation taken into account in all possible risks of physical restraint.

Anticoagulation and psychotropic medications

Anticoagulants and psychotropic medications are commonly prescribed together. Thus, the potential for interaction exists. Whereas thrombolytics and heparins are implicated in few pharmacokinetic interactions, warfarin and platelet inhibitors have been implicated in various interactions with psychotropic medications. In this article, I review the various psychotropic drug classes' relationships to anticoagulants. In a field devoid of randomized, placebo-controlled trials, clinical vigilance is advised when managing patients on concomitant therapy.

Risk of venous thromboembolism due to antipsychotic drug therapy

An increasing number of reports suggest a link between venous thromboembolism (VTE) and the use of antipsychotics. To better understand this association the available body of evidence has been critically scrutinised. Relevant articles were identified in the databases Scopus and PubMed. Several observational studies using different methodologies show an increased risk of VTE in psychiatric patients. This elevated risk seems to be related to the use of antipsychotic medication and in particular to the use of clozapine and low-potency first-generation drugs. Many studies investigating the association have, however, methodological limitations. The biological mechanisms involved in the pathogenesis of this possible adverse reaction are largely unknown but several hypotheses have been suggested such as drug-induced sedation, obesity, increased levels of antiphospholipid antibodies, enhanced platelet aggregation, hyperhomocysteinemia and hyperprolactinemia. The association may also be related to underlying risk factors present in psychotic patients. Physicians need to be aware of this possible adverse drug reaction. Although supporting evidence has not been published they should consider discontinuing or switching the antipsychotic treatment in patients experiencing VTE. In addition, although data is lacking, the threshold for considering prophylactic antithrombotic treatment should be low when risk situations for VTE arise, such as immobilisation, surgery and so on.