Clozapine modulates retinoid homeostasis in human brain and normalizes serum retinoic acid deficit in patients with schizophrenia

The atypical antipsychotic clozapine is one of the most potent drugs of its class, yet its precise mechanisms of action remain insufficiently understood. Recent evidence points toward the involvement of endogenous retinoic acid (RA) signaling in the pathophysiology of schizophrenia. Here we investigated whether clozapine may modulate RA-signaling. Effects of clozapine on the catabolism of all-trans RA (at-RA), the biologically most active metabolite of Vitamin A, were assessed in murine and human brain tissue and peripheral blood-derived mononuclear cells (PBMC). In patients with schizophrenia with and without clozapine treatment and matched healthy controls, at-RA serum levels and blood mRNA expression of retinoid-related genes in PBMCs were quantified. Clozapine and its metabolites potently inhibited RA catabolism at clinically relevant concentrations. In PBMC-derived microsomes, we found a large interindividual variability of the sensitivity toward the effects of clozapine. Furthermore, at-RA and retinol serum levels were significantly lower in patients with schizophrenia compared with matched healthy controls. Patients treated with clozapine exhibited significantly higher at-RA serum levels compared with patients treated with other antipsychotics, while retinol levels did not differ between treatment groups. Similarly, in patients without clozapine treatment, mRNA expression of RA-inducible targets CYP26A and STRA6, as well as at-RA/retinol ratio, were significantly reduced. In contrast, clozapine-treated patients did not differ from healthy controls in this regard. Our findings provide the first evidence for altered peripheral retinoid homeostasis in schizophrenia and suggest modulation of RA catabolism as a novel mechanism of action of clozapine, which may be useful in future antipsychotic drug development.

Impact and differences of illness course perception on the desire for social distance towards people with symptoms of depression or schizophrenia in Hanoi, Vietnam

OBJECTIVES

Public stigma against psychiatric disorders leads to delayed treatment utilization and worsens treatment outcome. This study analyses the impact of expectations regarding the course of illness and attribution as medical illness on the desire for social distance towards schizophrenia and depression in Vietnam.

METHODS

In 2013, a survey (n = 771) using unlabelled vignettes either depicting a person with symptoms typical for schizophrenia or major depression was carried out in Hanoi. All respondents had to indicate whether the person was suffering from a medical illness or not. As an indicator of public stigma, the desire for social distance was measured. A possible correlation between expectations towards the course of illness and social distance was evaluated using a linear regression model.

RESULTS

85 % of respondents endorsed that the person depicted in the schizophrenia vignette had a mental illness, compared to only 60 %, who were confronted with the depression vignette. This attribution of mental illness was correlated with higher levels of desire for social distance only in the schizophrenia vignette. While in the case of schizophrenia negative prognostic perceptions were associated with more desire for social distance, in the event of depression, it was only the expectation of lifelong dependency. Moreover, only for depression, positive expectations towards the course of illness correlated with less desire for social distance.

CONCLUSION

These results indicate an impact of prognostic expectations on the desire for social distance and support strategies that aim at maintaining social integration and strengthening autonomy.

Mental Health Determinants Among a Psychiatric Outpatient Sample of Vietnamese Migrants in Germany

Background: Mental health risk-factors for Asian migrants have been studied almost exclusively in the US, Canada, and Australia but not in European countries. Therefore, we aimed to identify sociodemographic, clinical, and migration-surrounding factors associated with experienced mental distress among Vietnamese migrants in Germany. Method: 305 Vietnamese migrants utilizing Germany's first Vietnamese psychiatric outpatient clinic filled out at admission the Brief-Symptom-Inventory 18 (BSI-18) as well as a questionnaire on 22 potential mental health determinants. Using a multiple linear regression model, we identified those sociodemographic, clinical, and migration-surrounding factors that were significantly related to the Global Severity Index (GSI) of the BSI-18. Results: The factors unemployment (B = -6.32, p = 0.014), financial problems (B = -10.71, p < 0.001), no or only little religious involvement (B = -3.23, p = 0.002), no psychiatric precontact (B = -7.35, p = 0.004), previous migration experiences (B = 8.76, p = 0.002), and perceived discrimination (B = 6.58, p = 0.011) were found to significantly increase the level of mental distress according to the BSI-GSI. Conclusion: Based on these results, we were able to construct a mental health risk-profile for Vietnamese migrants in Germany, which aims to detect candidates for psychiatric problems earlier and supply them with customized prevention and therapy options.

The relationship between causal beliefs and desire for social distance towards people with schizophrenia and depression: Results from a survey of young Ghanaian adults

This study examines attitudes of the young Ghanaian population regarding the relationship between causal beliefs and desire for social distance from people with symptoms of schizophrenia and depression. Respondents (n = 507) were presented with depression and schizophrenia symptoms using unlabeled case vignettes. A factor analysis examined three factors for causal beliefs, and multiple linear regression analysis on the desire for social distance was conducted. The desire for social distance was higher when symptoms in both case-vignettes were attributed to childhood adversities and overall lower when respondents lived in northern regions of Ghana. Only, for vignettes depicting schizophrenia, mental illness attribution was associated with more desire for social distance. Significant gender effects were found for depression vignettes only: female respondents reported significantly more desire for social distance, whereas female gendered vignettes were associated with less desire for social distance by respondents of both genders.

Treatment recommendation differences for schizophrenia and major depression: a population-based study in a Vietnamese cohort

Background

In Vietnam, the mental health care infrastructure is on the verge of transformation with an increase in the demand for access to adequate and effective mental health care services. Public attitudes towards mental illness, as well as corresponding treatment options influence help-seeking behaviors of patients and caregivers, affecting the course of their treatment. This study assesses attitudes towards treatment options for depression and schizophrenia, as the two most common psychiatric disorders in Vietnam, accounting for at least 75% of all psychiatric inpatients.

Methods

A general population-based survey was conducted in Hanoi, Vietnam between April and August 2013. Participants received a description of a person with symptoms of either depression (n = 326) or schizophrenia (n = 403) and were asked to give recommendations for adequate sources of mental health support and treatment options. Multiple analyses on a single item level compared the likelihood of recommendation between schizophrenia and depression.

Results

Overall, respondents recommended health care services, ranging from seeking mental health care professionals, psychotherapists, and psychiatrists for both disorders. Psychotherapy was the most favored treatment method, whereas further treatment options, such as concentration and relaxation exercises, meditation or yoga and psychotropic medication were also endorsed as helpful. For the schizophrenia vignette condition, psychotherapy, visiting a psychiatrist or psychotherapist received stronger endorsement rates as compared to the depression vignette. Furthermore, ECT, Feng Shui-based practices, praying and visiting natural healers were recommended less by respondents for the depression vignette in comparison with the schizophrenia vignette.

Conclusions

The Vietnamese public endorsed evidence-based treatment recommendations from a variety of treatments options. Differences in the treatment recommendations between depression and schizophrenia reflected the perceived severity of each disorder. Further developments of the Vietnamese mental health care system concerning mental health care providers, as well as the legal regulations surrounding the provision of psychotherapy are needed.

Impact of perceived course of illness on the desire for social distance towards people with symptoms of schizophrenia in Hanoi, Vietnam

In Vietnam, stigmatisation and discrimination of patients with mental illness are highly prevalent. This study explores whether the perception of course of illness of people with symptoms indicating schizophrenia is associated with the desire for social distance in the Vietnamese public. A population-based survey (n = 455) using unlabelled vignettes for schizophrenia was carried out in the Hanoi municipality in 2013. First, a factor analysis was performed to group items indicating perception of prognosis. Second, a linear regression analysis was used to search for correlations between these expectations and desire for social distance. The factor analysis revealed three independent factors of perception of course of illness: (1) loss of social integration and functioning, (2) lifelong dependency on others, and (3) positive expectations towards treatment outcome. Both factors with negative prognostic perceptions (1&2) were associated with more desire for social distance. The results indicate a link between social acceptance and the perceived ability to maintain a social role including a capability of reciprocity within the Vietnamese society. Additionally, these findings highlight the importance of preserving social functioning in any treatment approach for patients with schizophrenia, which includes psychosocial intervention and rehabilitation programs.

Public attitude towards restrictions on persons with mental illness in greater Hanoi area, Vietnam

BACKGROUND AND AIMS

In recent years, there has been a growing awareness of the need to protect human rights in psychiatry. Within the last years, considerable effort has been made to reduce restrictive measures in mental health settings. Reducing restrictive measures within mental health care has also moved increasingly into the focus of public debate. This study aims, for the first time in a Southeast Asian sample, to explore whether socio-demographic factors affect public attitudes toward restrictions on mentally ill people in Hanoi, Vietnam.

METHODS

A general population-based survey (self-report questionnaire) was carried out in 2013 in the greater Hanoi area. The survey sample ( N = 813) was recruited according to the latest published census (2009) and micro-census (2013) in Vietnam and Hanoi with regard to the socio-demographic factors gender, age, urbanity, household size and marital status. Multinomial logistic regressions for odds ratios with 95% confidence intervals were calculated to examine the influence of epidemiological variables, like gender and age, on the public attitude toward restrictions imposed on mentally ill people in Vietnam.

RESULTS

This study found, for the first time in a large Vietnamese sample, that gender and age were associated with public attitudes toward restrictions on mentally ill people. In detail, significantly fewer men endorsed compulsory admission to a hospital and abortion than Vietnamese women. In addition, endorsement of abortion was significantly higher in older people.

CONCLUSION

The results offer some insight into roles of women in the Vietnamese society and might reflect the traditional gender expectations in Vietnamese families. Moreover, the results emphasize the need for supporting female psychiatric patients and their families within their communities and in the Vietnamese society.

Public attitudes towards psychiatrists in the metropolitan area of Hanoi, Vietnam

OBJECTIVES

Mental health associated stigmatization remains problematic in low and middle-income countries, thus preventing patients from adequate access to psychiatric care. Public attitudes towards psychiatrists have not been examined in many countries, especially not in Vietnam where merely one psychiatrist per 300.000 population is available. The study aims to explore attitudes towards psychiatrists in the Hanoi municipality and to identify socio-demographical factors that influence these attitudes.

METHODS

Between April and August 2013, a general population-based survey was carried out in the greater Hanoi area, Vietnam. The sample of 817 participants was stratified according to the latest Vietnamese census (2009) and micro-census (2013) with regards to socio-demographic factors. Multivariate analyses were conducted to determine the influence of these factors on attitudes towards psychiatrists.

RESULTS

Gender and religious beliefs significantly influenced public attitudes towards psychiatrists. Male participants reported significantly more negative perception towards psychiatrists compared to female respondents. Participants following a religion reported significantly more negative attitudes toward psychiatrists than those without self-reported religious attainment.

CONCLUSIONS

Negative attitudes towards psychiatrists are associated with religious beliefs and gender affiliation in the greater Hanoi area. A strategy that involves religious institutions in raising awareness about mental health issues while considering public's socio-cultural attitudes may pave the way for greater potentialities of adequate psychiatric care, destigmatize the mental health system, and care provider.

Perceived stigmatization and discrimination of people with mental illness: A survey-based study of the general population in five metropolitan cities in India

BACKGROUND

India faces a significant gap between the prevalence of mental illness among the population and the availability and effectiveness of mental health care in providing adequate treatment. This discrepancy results in structural stigma toward mental illness which in turn is one of the main reasons for a persistence of the treatment gap, whereas societal factors such as religion, education, and family structures play critical roles. This survey-based study investigates perceived stigma toward mental illness in five metropolitan cities in India and explores the roles of relevant sociodemographic factors.

MATERIALS AND METHODS

Samples were collected in five metropolitan cities in India including Chennai (n = 166), Kolkata (n = 158), Hyderabad (n = 139), Lucknow (n = 183), and Mumbai (n = 278). Stratified quota sampling was used to match the general population concerning age, gender, and religion. Further, sociodemographic variables such as educational attainment and strength of religious beliefs were included in the statistical analysis.

RESULTS

Participants displayed overall high levels of perceived stigma. Multiple linear regression analysis found a significant effect of gender (P < 0.01), with female participants showing higher levels of perceived stigma compared to male counterparts.

CONCLUSION

Gender differences in cultural and societal roles and expectations could account for higher levels of perceived stigma among female participants. A higher level of perceived stigma among female participants is attributed to cultural norms and female roles within a family or broader social system. This study underlines that while India as a country in transition, societal and gender rules still impact perceived stigma and discrimination of people with mental illness.

Acculturation and severity of depression among first-generation Vietnamese outpatients in Germany

BACKGROUND

Challenges of migration, particularly concerning the process of acculturation are associated with an increased risk of mental illness. Vietnamese migrants constitute the largest Southeast Asian migrant group in Germany, yet there is no data on the relationship between the mental health status and acculturation among this population.

AIMS

Therefore, the present study examines the relationship between two well-established dimensions of acculturation, that is, dominant society immersion (DSI) and ethnic society immersion (ESI), the four resulting acculturation strategies (integration, assimilation, separation and marginalization), and severity of depression.

METHODS

A sample of N = 113 first-generation Vietnamese outpatients from a psychiatric outpatient clinic for Vietnamese migrants in Germany was studied regarding their self-reported depressive symptoms (Beck Depression Inventory-II (BDI-II)) and acculturation (Stephenson Multigroup Acculturation Scale (SMAS)).

RESULTS

Consistent with the hypotheses, patients reported less severe depressive symptoms, when they reported higher orientation toward the German and the Vietnamese society. Moreover, the results showed that integrated patients reported a lower severity of depression compared to marginalized patients, who reported the highest severity of depression.

CONCLUSIONS

The findings indicate that among a sample of first-generation Vietnamese patients with depression, an orientation to both, the mainstream society and one's heritage society might serve as a potential resource. The rejection of any orientation to any society is associated with an increased risk for depression.

Attitude toward psychiatrists and psychiatric medication: A survey from five metropolitan cities in India

BACKGROUND

Stigmatization and overall scarcity of psychiatrists and other mental health-care professionals remain a huge public health challenge in low- and middle-income countries, more specifically in India. Most patients seek help from faith healers, and awareness about psychiatrists and treatment methods is often lacking. Our study aims to explore public attitudes toward psychiatrists and psychiatric medication in five Indian metropolitan cities and to identify factors that could influence these attitudes.

MATERIALS AND METHODS

Explorative surveys in the context of public attitudes toward psychiatrists and psychiatric medication were conducted using five convenience samples from the general population in Chennai (n = 166), Kolkata (n = 158), Hyderabad (n = 139), Lucknow (n = 183), and Mumbai (n = 278). We used a quota sample with respect to age, gender, and religion using the census data from India as a reference.

RESULTS

Mean scores indicate that attitudes toward psychiatrists and psychiatric medication are overall negative in urban India. Negative attitudes toward psychiatrists were associated with lower age, lower education, and strong religious beliefs. Negative attitudes toward psychotropic medication were associated with lower age, male gender, lower education, and religion.

CONCLUSION

In line with the National Mental Health Policy of India, our results support the perception that stigma is widespread. Innovative public health strategies are needed to improve the image of psychiatrists and psychiatric treatment in society and ultimately fill the treatment gap in mental health.

Acculturation strategies and severity of depression among Vietnamese migrants

Aims

Migration with its long-term changes and the resulting task to adjust to the new environment has been associated with an increased risk for mental health problems. This study aims to gain further insight on the relationship between the fours acculturations strategies (integration, assimilation, separation, marginalization) and severity of depression.

Methods

A total of n = 79 first generation Vietnamese outpatients from a psychiatric outpatient clinic for Vietnamese migrants in Germany were investigated regarding self-reported depressive symptoms (patient health questionnaire-9) and acculturation (Stephenson multigroup acculturation scale; SMAS).

Results

Patients with an integration acculturation strategy reported lower severity of depression compared to marginalized patients, who reported the highest severity of depression.

Conclusion

The results implicate that the integration of both the mainstream society and the ethnic society might serve as a resource, whereas the rejection of both societies might increase the risk of depression.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Differences in symptom expression between Vietnamese and German patients utilizing a psychiatric outpatient service using the PHQ

Objective

Despite a large body of work on somatic symptom presentation among people of Asian descent, research has shown heterogeneous results. Examining symptom presentation in clinically and ethnically well-characterized populations constitutes a first step towards better understanding differing patterns symptom of presentation. This is the first larger study aiming to compare Vietnamese and German psychiatric outpatients regarding symptom presentation.

Methods

110 Vietnamese and 109 German patients seeking psychiatric treatment at two outpatient clinic services in Berlin were asked to complete the patient health questionnaire (PHQ). Comparisons of Vietnamese and German patients were conducted using independent t-tests. The somatic symptom module (PHQ-15), the depression module (PHQ-9) and the original PHQ-modules examining anxiety and psychosocial stress levels were compared for both groups using multivariate analysis. Categorical variables were evaluated using Chi2 analysis. Crohnbach's alpha was calculated separately for both groups and all PHQ modules.

Results

Vietnamese patients endorsed significantly higher levels of somatic symptoms overall and on individual somatic items, such as pain-related disturbancies. Yet, German and Vietnamese patients did not differ in terms of depression severity. Vietnamese patients with fewer German language skills showed a significantly higher tendency for somatization. While German patients showed higher total scores on the anxiety- and stress-modules of the PHQ, this difference was not statistically significant. Vietnamese and German patients showed comparable Crohnbach's alpha for all subscales.

Conclusion

As data was collected from both groups upon the first visit to an outpatient clinic, the symptoms reported could be reflective of culture related symptom awareness when feeling discomfort in the context of mental illness.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Relationship between migration-stressors and self-reported symptoms of depression in an outpatient sample of Vietnamese migrants in Germany

Introduction

Vietnamese migrants under the influence of migration-related stressors (MRS) represent a vulnerable group within the mental health care system in Germany.

Aims

First study examining the relationship between the quantity of experienced MRS and the severity of self-reported symptoms of depression in a Vietnamese outpatient-sample.

Methods

137 first-generation Vietnamese migrants diagnosed with depression were asked to complete the BDI-II and 24 questions about stressful experiences related to the migration process. Linear regression models was performed to examine the influence of the MRS-quantity on BDI-II total score and on BDI-II subscales (Buckley et al., 2001).

Results

A higher number of experienced MRS was found to be related to a higher BDI-II total score, as well as to a higher score on the cognitive subscale in particular. Regarding the cognitive depression-dimension the BDI-II items pessimism, past failure, guilt feelings, punishment feelings and suicidal thoughts were positively related to the MRS-quantity.

Discussion and conclusion

A dose-response-relationship was found, with a higher number of MRS being related to a higher severity level of self-reported depressiveness as well as to a higher level of cognitive depression-symptoms in particular. The increase in suicidal ideations in the light of MRS-exposure is in line with findings from other migrant populations. Therapeutic interventions may focus (more) on depressive cognitions as a result of recurring MRS-experiences. Special attention should be placed on suicidal thoughts being boosted by MRS.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Hypothalamic-Pituitary-Adrenocortical Dysfunction in Elderly, Male Marathon Runners: Feedback Sensitivity, Stress Response, and Effects on Verbal Memory

Animal studies suggest that repeated episodes of elevated glucocorticoids lead to a dysregulation of the hypothalamic-pituitary-adrenal (HPA) system at a suprapituitary level, and to impaired mnemonic function. We compared cognitive tests, as well as feedback integrity and stress responsivity of the HPA system, between 11 elderly, male marathon runners - a model of repeated HPA system activation - and 10 sedentary controls. The marathon runners had significantly increased baseline, stress, and post-stress ACTH - but not cortisol - concentrations. Also, suppression of ACTH by 3 mg dexamethasone was impaired in the athletes compared to the control subjects, while the ACTH and cortisol response to additional CRH did not differ between the 2 groups. Finally, long-term verbal memory was impaired in the athletes compared to the controls. Regarding the HPA system, these findings are in accordance with an acquired suprapituitary feedback disturbance in marathon runners; however, the similar glucocorticoid concentrations in the 2 groups may be due to reduced adrenal sensitivity to ACTH. Together with impaired verbal memory, these data support the assumption that repeated episodes of HPA system activity may exert negative effects at the level of the hippocampus.

Influence of urbanity on perception of mental illness stigma: a population based study in urban and rural Hanoi, Vietnam

BACKGROUND AND AIMS

To examine, for the first time in Vietnam, whether urbanity of respondents among other socio-demographic factors affects the public perception of stigma attached to persons with mental illness in Hanoi.

METHODS

A general population-based survey was carried out in 2013 in the greater Hanoi area. The perception of stigma attached to people with mental illness was elicited using Link's perceived discrimination and devaluation scale (PDDS) carried out in Vietnamese language. The survey sample (n = 806) was stratified for gender, urban/rural location, age, household size and marital status, in accordance with the 2013 Vietnamese census.

RESULTS

Comparing the total score of the PDDS and its single items, we found less perceived stigma and discrimination among the rural population of Hanoi and in respondents who reported religious attainment to either Buddhism or Christianity. Logistic regression analyses found no significant influences of gender, age, household size or marital status regarding the perceived stigma toward persons with mental illness.

CONCLUSION

Less negative perception of stigma attached to persons with mental illness that was observed among the rural population in the Hanoi area may be interpreted in the light of possibly more demanding living conditions in modern urban Vietnam with less opportunities for mentally ill patients and points toward a dynamic interaction with rapidly changing living conditions in Asian megacities.

Perceived stigma of mental illness: A comparison between two metropolitan cities in India

PURPOSE

An increasing number of comparative studies are conducted on the stigmatization of persons with mental illness, in particular with regard to regional and diachronic variation. So far, there have been no studies comparing stigmatization of persons with mental illness in two different regions of India. Therefore, we examined the differences in perception of stigma attached to mental illnesses in Kolkata and Chennai, with regard to cultural and geographical differences to better understand the roots and origins of this issue.

MATERIALS AND METHODS

Explorative surveys in the context of public attitudes toward people with mental disorders were conducted among conveniently selected members of the general population in Chennai (n = 166) and Kolkata (n = 158) with identical methodology. Link's perceived devaluation-discrimination measure was used. The samples were matched for age, gender, and education.

RESULTS

The calculated sum score indicated that respondents from Kolkata had a higher level of perceived discrimination toward persons with mental illness than respondents from Chennai (P = 0.043). Furthermore, regression analysis revealed that lower perceived stigma was associated with stronger religious devotion (P = 0.049) and higher educational attainment (P = 0.001) in both cities.

DISCUSSION

The results showed that perceived stigma was higher in Kolkata than in Chennai. The correlation of higher stigma with lower education was in line with the previous research, and interestingly, it was found that higher stigma correlated with weaker religious devotion. Further studies exploring a wider variety of factors may provide us with a better understanding of the roots of perceived stigma in India.

Mirror neuron deficit in schizophrenia: Evidence from repetition suppression

BACKGROUND

Schizophrenia is associated with impaired cognition, especially cognition in social contexts. The mirror neuron system (MNS) serves as an important neuronal basis for social cognitive skills; however, previous investigations on the integrity of MNS function in schizophrenia remain approximate.

METHODS

We employed a repetition suppression paradigm that allows for measuring neuronal responses to gesture observation and gesture execution. Cross-modal repetition suppression, i.e., adaptation between observe/execute and execute/observe conditions, was defined as the decisive experimental condition characterizing the unique sensori-motor properties of mirror neurons. Event-related potentials (ERPs) were assessed in 15 schizophrenia patients and 15 matched controls.

RESULTS

We isolated an ERP signature of specific adaptation effects to identical hand gestures. Of critical importance, this ERP signature indicated intact intra-modal adaptive pattern, i.e., observe/observe and execute/execute, of comparable magnitude between groups, but deficient cross-modal adaptation, i.e., observe/execute and execute/observe, in schizophrenia patients.

CONCLUSION

Our data provide robust evidence that pure perception and execution of hand gestures are relatively intact in schizophrenia. In contrast, visuo-motor transformation processes mediated by the MNS seem to be specifically disturbed in schizophrenia. These results unambiguously demonstrate MNS deficits in schizophrenia and extend our understanding of the neuronal bases of social dysfunction in this disorder.

Smoking improves divided attention in schizophrenia

RATIONALE

Smoking is highly prevalent in schizophrenia, and there is evidence for beneficial effects on neurocognition. Smoking is therefore hypothesized a self-medication in schizophrenia. Although much effort is devoted to characterize those cognitive domains that potentially benefit from smoking, divided attention has not yet been investigated.

OBJECTIVES

The aim of this study was to analyze the interactional effects of diagnosis of schizophrenia and smoking history on divided attention.

METHODS

We investigated behavioral measures of divided attention in a sample of 48 schizophrenic patients and 48 controls (24 current smokers and non-smokers each) carefully matched for age, sex, education, verbal IQ, and smoking status with general linear models.

RESULTS

Most important within the scope of this study, significant interactions were found for valid reactions and errors of omission: Performance substantially increased in smoking schizophrenic patients, but not in controls. Further, these interactions were modified by sex, driven by female schizophrenic patients who showed a significant behavioral advantage of smokers over non-smokers, other than male schizophrenic patients or healthy controls who did not express this sex-specific pattern.

CONCLUSIONS

Results suggest a positive effect of smoking history on divided attention in schizophrenic patients. This study provides first evidence that the complex attention domain of divided attention is improved by smoking, which further substantiates the self-medication hypothesis of smoking in schizophrenia, although this has been shown mainly for sustained and selective attention. Gender-specific effects on cognition need to be further investigated.

Neurocognitive pattern analysis reveals classificatory hierarchy of attention deficits in schizophrenia

Attention deficits, among other cognitive deficits, are frequently observed in schizophrenia. Although valid and reliable neurocognitive tasks have been established to assess attention deficits in schizophrenia, the hierarchical value of those tests as diagnostic discriminants on a single-subject level remains unclear. Thus, much research is devoted to attention deficits that are unlikely to be translated into clinical practice. On the other hand, a clear hierarchy of attention deficits in schizophrenia could considerably aid diagnostic decisions and may prove beneficial for longitudinal monitoring of therapeutic advances. To propose a diagnostic hierarchy of attention deficits in schizophrenia, we investigated several facets of attention in 86 schizophrenia patients and 86 healthy controls using a set of established attention tests. We applied state-of-the-art machine learning algorithms to determine attentive test variables that enable an automated differentiation between schizophrenia patients and healthy controls. After feature preranking, hypothesis building, and hypothesis validation, the polynomial support vector machine classifier achieved a classification accuracy of 90.70% ± 2.9% using psychomotor speed and 3 different attention parameters derived from sustained and divided attention tasks. Our study proposes, to the best of our knowledge, the first hierarchy of attention deficits in schizophrenia by identifying the most discriminative attention parameters among a variety of attention deficits found in schizophrenia patients. Our results offer a starting point for hierarchy building of schizophrenia-associated attention deficits and contribute to translating these concepts into diagnostic and therapeutic practice on a single-subject level.

[Mental Health Care Utilization of First Generation Vietnamese Migrants in Germany]

OBJECTIVE

Vietnamese migrants underutilize and are a "hard to reach group" within the existing mental health care system in Germany.

METHODS

We analyzed migration related and clinical data for all first-time Vietnamese migrants seeking psychiatric help, within the first 30 months of a newly established outpatient clinic, offering culture-sensitive psychiatric treatment in native Vietnamese language.

RESULTS

Most first time patients were female, first generation Vietnamese migrants with poor German language skills. Only 1 /3 of all patients had a psychiatric history, while this number was higher in patients with schizophrenia. Over time, more first time patients with depression were seeking psychiatric care, accompanied with an increase of non-professional referrals within the Vietnamese communities.

CONCLUSION

This first study on mental health care utilization in Vietnamese migrants in Germany points towards the fact that "migrants" cannot be considered as a homogeneous group. Mental health care utilization must be evaluated for specific migrant groups, and can be initially improved if offered in native language and when it is referred to by members of migrant communities.

Assessing long-term test-retest reliability of the CPT-IP in schizophrenia

Background

The Continuous Performance Test-Identical Pairs version (CPT-IP) is a well-established measure of sustained attention, and its more challenging versions are particularly suited to detect subtle processing deficits in patients with schizophrenia. However, while there are few longitudinal samples for the CPT-IP, no study has addressed stability for more than two month in patients with schizophrenia. Assessing long-term test-retest reliability of the CPT-IP would facilitate the ability of clinicians to draw conclusions from studies involving interventions as long term cognitive or pharmacological treatments. The present study assessed 12 month test-retest reliability for the two most challenging versions of CPT-IP (4-digit and shapes) in a matched sample of clinically stable schizophrenia outpatients and healthy controls.

Methods

Fifty clinically stable schizophrenia outpatients and 50 healthy controls were assessed with the CPT-IP for the 4-digit and shape conditions. From these, 40 patients and 47 controls were reassessed with an average interval of 12.3 months between test sessions. Test-retest reliability was analyzed with Pearson correlations and results were compared with previous data involving healthy controls and short-term studies in patients with schizophrenia.

Results

Especially d’ and hit rate discriminated well between patients with schizophrenia and healthy controls for both CPT-IP conditions and at both test sessions. Healthy controls demonstrated sufficient long term test-retest correlations of d’, hit rate and reaction time for both the 4-digit and shape conditions. However, in schizophrenia patients, long-term reliability correlations were at best moderate for d’ and hit rate only.

Conclusions

The current study provides further evidence that d’ and hit rate yield consistent cross-sectional discrimination sensitivity. At best moderate long-term test-retest reliability of d’ in schizophrenia outpatients may be not sufficient for practical use of this measure in long term clinical trials.

Effects of smoking history on selective attention in schizophrenia

Smoking prevalence is highly elevated in schizophrenia compared to the general population and to other psychiatric populations. Evidence suggests that smoking may lead to improvements of schizophrenia-associated attention deficits; however, large-scale studies on this important issue are scarce. We examined whether sustained, selective, and executive attention processes are differentially modulated by long-term nicotine consumption in 104 schizophrenia patients and 104 carefully matched healthy controls. A significant interaction of 'smoking status' × 'diagnostic group' was obtained for the domain of selective attention. Smoking was significantly associated with a detrimental conflict effect in controls, while the opposite effect was revealed for schizophrenia patients. Likewise, a positive correlation between a cumulative measure of nicotine consumption and conflict effect in controls and a negative correlation in patients were found. These results provide evidence for specific directional effects of smoking on conflict processing that critically dissociate with diagnosis. The data supports the self-medication hypothesis of smoking in schizophrenia and suggests selective attention as a specific cognitive domain targeted by nicotine consumption. A potential mechanistic model explaining these findings is discussed.

Test-retest reliability of Attention Network Test measures in schizophrenia

BACKGROUND

The Attention Network Test (ANT) is a well established behavioral measure in neuropsychological research to assess three different facets of selective attention, i.e., alerting, orienting, and conflict processing. Although the ANT has been applied in healthy individuals and various clinical populations, data on retest reliability are scarce in healthy samples and lacking for clinical populations. The objective of the present study was a longitudinal assessment of relevant ANT network measures in healthy controls and schizophrenic patients.

METHODS

Forty-five schizophrenic patients and 55 healthy controls were tested with ANT in a test-retest design with an average interval of 7.4 months between test sessions. Test-retest reliability was analyzed with Pearson and Intra-class correlations.

RESULTS

Healthy controls revealed moderate to high test-retest correlations for mean reaction time, mean accuracy, conflict effect, and conflict error rates. In schizophrenic patients, moderate test-retest correlations for mean reaction time, orienting effect, and conflict effect were found. The analysis of error rates in schizophrenic patients revealed very low test-retest correlations.

CONCLUSIONS

The current study provides converging statistical evidence that the conflict effect and mean reaction time of ANT yield acceptable test-retest reliabilities in healthy controls and, investigated longitudinally for the first time, also in schizophrenia. Obtained differences of alerting and orienting effects in schizophrenia case-control studies should be considered more carefully. The analysis of error rates revealed heterogeneous results and therefore is not recommended for case control studies in schizophrenia.

Visual P3 amplitude modulation deficit in schizophrenia is independent of duration of illness

BACKGROUND

In the search for markers of schizophrenia, functional deficits during inhibition have been a major focus. In previous studies, we found a reduced amplitude modulation of the visual P3 component of the event-related potential (ERP) in schizophrenic patients during inhibition in the Attention Network Test (ANT). The objective of the present study was to explore whether this deficit exhibits properties of a trait or state marker of schizophrenia.

METHODS

Eighteen recent onset inpatients and eighteen chronic schizophrenic outpatients as well as 36 healthy controls, including a young adult and an old adult group to match recent onset and chronic illness groups for age and sex, were included. Participants were tested with ANT while 32-channel electroencephalogram was recorded and visual P3 amplitudes were analyzed. Amplitude modulation was defined as the variation of P3 amplitude at Pz as a function of ANT flanker conditions.

RESULTS

There were no significant behavioral between-group differences in terms of alerting, orienting, and inhibition. Mean visual P3 was significantly lower in schizophrenic patients than in healthy controls. Parietal P3 amplitude was significantly less modulated in both recent onset (-0.035) and chronic schizophrenic patients (-0.081) compared with young (-0.588; p<0.05) and older healthy controls, respectively (-0.556; p<0.05). No correlations were obtained between P3 modulation and clinical or demographic variables.

CONCLUSION

The results provide evidence that the observed deficit of visual P3 amplitude modulation is independent of duration of illness and age and may contain properties of a trait marker of schizophrenia.

Candidate gene analysis identifies a polymorphism in HLA-DQB1 associated with clozapine-induced agranulocytosis

OBJECTIVE

Clozapine is considered to be the most efficacious drug to treat schizophrenia, although it is underutilized, partially due to a side effect of agranulocytosis. This analysis of 74 candidate genes was designed to identify an association between sequence variants and clozapine-induced agranulocytosis (CIA).

METHOD

Blood and medical history were collected for 33 CIA cases and 54 clozapine-treated controls enrolled between April 2002 and December 2003. Significant markers from 4 genes were then assessed in an independently collected case-control cohort (49 CIA cases, 78 controls).

RESULTS

Sequence variants in 5 genes were found to be associated with CIA in the first cohort: HLA-DQB1, HLA-C, DRD1, NTSR1, and CSF2RB. Sequence variants in HLA-DQB1 were also found to be associated with CIA in the second cohort. After refinement analyses of sequence variants in HLA-DQB1, a single SNP (single nucleotide polymorphism), 6672G>C, was found to be associated with risk for CIA; the odds of CIA are 16.9 times greater in patients who carry this marker compared to those who do not.

CONCLUSIONS

A sequence variant (6672G>C) in HLA-DQB1 is associated with increased risk for CIA. This marker identifies a subset of patients with an exceptionally high risk of CIA, 1,175% higher than the overall clozapine-treated population under the current blood-monitoring system. Assessing risk for CIA by testing for this and other genetic variants yet to be determined may be clinically useful when deciding whether to begin or continue treatment with clozapine.

Single-subject classification of schizophrenia by event-related potentials during selective attention

BACKGROUND

Executive dysfunction has repeatedly been proposed as a robust and promising substrate of analytical approaches in the research of neurocognitive markers of schizophrenia. Here, we present a mixed model- and data-driven classification approach by applying a task that targets executive dysfunction in schizophrenia and by investigating relevant event-related potential (ERP) features with machine learning classifiers.

METHODS

Forty schizophrenic patients and forty matched healthy controls completed the Attention Network Test while an electroencephalogram was recorded. Target-locked N1 and P3 ERP components were constructed and submitted to different classification analyses without a priori hypotheses. Standardized source localization was applied to estimate neural sources of N1 and P3 deficits in schizophrenia.

RESULTS

We obtained a classification accuracy of 79% using only very few ERP components. Central P3 components following compatible and incompatible trials and right parietal N1 latencies averaged across targets and were sufficient for classification. P3 deficits were associated with anterior cingulate cortex dysfunction, while right posterior current density deficits were observed in schizophrenia during the N1 time frame.

CONCLUSIONS

The data exemplarily show how automated inference may be applied to classify a pathological state in single subjects without prior knowledge of their diagnoses. While classification accuracy may be optimized by application of other executive paradigms, this approach illustrates the potential of machine learning algorithms for the identification of biomarkers that are independent of clinical assessments. Conversely, data suggest a pathophysiological mechanism that includes early visual and late executive deficits during response inhibition in schizophrenia.

Evidence of specificity of a visual P3 amplitude modulation deficit in schizophrenia

BACKGROUND

In a previous study, we found a reduced amplitude modulation of the visual P3 component of the event-related potential (ERP) in schizophrenic patients compared with healthy controls during inhibition in the Attention Network Test (ANT). The objective of the present study was to replicate this finding and to explore whether this cortical processing deficit is specific to schizophrenia.

METHODS

Sixteen schizophrenic patients, sixteen depressive patients, and sixteen healthy controls matched for age, sex, and education were included. Participants were tested with the ANT, a test of selective attention that provides behavioral estimates for alerting, orienting, and inhibition. 32-Channel electroencephalogram was recorded and visual P3 amplitudes were topographically analyzed and compared between groups.

RESULTS

There were no significant behavioral between-group differences in terms of mean reaction time, accuracy, and ANT effects alerting, orienting, and inhibition. Absolute visual P3 amplitude was not reduced in schizophrenia or depression. P3 amplitude modulation was defined as P3 amplitude at Pz as a function of ANT flanker conditions. We found a parietal P3 amplitude modulation deficit in schizophrenic patients (-.015) that was absent in both healthy controls (-.705; p = .002) and depressive patients (-1.022; p = .001).

CONCLUSION

The results provide evidence that a deficit of visual P3 amplitude modulation distinguishes schizophrenia from healthy and disease controls and provides greater discriminative power than absolute visual P3 amplitude.

Association of HTR2C, but not LEP or INSIG2, genes with antipsychotic-induced weight gain in a German sample

Background: Drug-induced bodyweight gain (BWG) is a serious concern in pharmacotherapy with second-generation antipsychotics. The interindividual variability is likely to be modulated by genetic factors. In the past, pharmacogenetic studies yielded conflicting results, and none of the identified genetic alterations exerts sufficient predictive value for this severe side effect of psychopharmacotherapy. Aim: We aimed to contribute to the replication and extension of prior association findings and investigated the genes encoding serotonin 2C receptor (HTR2C), insulin-induced gene 2 (INSIG2) and leptin (LEP). Patients & methods: We investigated the association of HTR2C, LEP and INSIG2 SNPs with antipsychotic-induced BWG in 128 German schizophrenic patients. Genotyping was performed for nine SNPs (HTR2C: rs498207, rs3813928, rs6318 and rs3813929; INSIG2: rs17587100, rs10490624, rs17047764 and rs7566605; LEP: rs7799039). Association analysis included logistic regression analysis and Pearson´s χ2 tests. Results: We report a significant association of three HTR2C SNPs (rs498207, rs3813928 and rs3813929) and of the respective haplotype with antipsychotic-induced BWG. Regarding the X-chromosomal SNP rs498207, individuals with AA/A genotype gained more weight than those with GG/G genotype. The association observed with the SNP rs498207 was also significant after correcting for multiple testing (p = 0.0196). No association was found for INSIG2 and LEP SNPs. Conclusion: The results contribute to the accumulating evidence for an association of the X-chromosomal HTR2C gene with antipsychotic-induced BWG. The proposed underlying mechanisms include decreased HTR2C gene expression with reduced 5-HT-modulated activation of hypothalamic proopiomelanocortin-neurons, and inverse 5-HT2C agonism in the presence of D2 receptor antagonism.

Event-related potentials associated with Attention Network Test

Selective visual attention is thought to be comprised of distinct neuronal networks that serve different attentional functions. The Attention Network Test (ANT) has been introduced to allow for assessment of alerting, orienting, and response inhibition. Information on associated measures of neural processing during ANT is still scarce. We topographically analyzed top-down ANT effects on visual event-related potential morphology in 44 healthy participants. Significant reaction time effects were obtained for all attention networks. Posterior cue-locked target N1 amplitude was significantly increased during both alerting and orienting. P3 amplitude was significantly modulated at frontal and parietal leads as a function of inhibition. Our data suggests that attentional mechanisms of alerting and orienting are employed simultaneously at early stages of the visual processing stream to amplify perceptual discrimination and load onto the same ERP component. Fronto-parietal modulations of P3 amplitude seem to mirror both response inhibition and visual target detection and may be interesting markers for further studies.

Attention Network Test reveals alerting network dysfunction in multiple sclerosis

Attention is one of the cognitive domains typically affected in multiple sclerosis. The Attention Network Test was developed to measure the function of the three distinct attentional networks, alerting, orienting, and executive control. The Attention Network Test has been performed in various neuropsychiatric conditions, but not in multiple sclerosis. Our objective was to investigate functions of attentional networks in multiple sclerosis by means of the Attention Network Test. Patients with relapsing—remitting multiple sclerosis (n = 57) and healthy controls (n = 57) matched for age, sex, and education performed the Attention Network Test. Significant differences between patients and controls were detected in the alerting network (p = 0.003), in contrast to the orienting (p = 0.696) and the conflict (p = 0.114) network of visual attention. Mean reaction time in the Attention Network Test was significantly longer in multiple sclerosis patients than in controls (p = 0.032), Multiple sclerosis patients benefited less from alerting cues for conflict resolution compared with healthy controls. The Attention Network Test revealed specific alterations of the attention network in multiple sclerosis patients which were not explained by an overall cognitive slowing.

Spatiotemporal mapping of sex differences during attentional processing

Functional neuroimaging studies have increasingly aimed at approximating neural substrates of human cognitive sex differences elicited by visuospatial challenge. It has been suggested that females and males use different behaviorally relevant neurocognitive strategies. In females, greater right prefrontal cortex activation has been found in several studies. The spatiotemporal dynamics of neural events associated with these sex differences is still unclear. We studied 22 female and 22 male participants matched for age, education, and nicotine with 29-channel-electroencephalogram recorded under a visual selective attention paradigm, the Attention Network Test. Visual event-related potentials (ERP) were topographically analyzed and neuroelectric sources were estimated. In absence of behavioral differences, ERP analysis revealed a novel frontal-occipital second peak of visual N100 that was significantly increased in females relative to males. Further, in females exclusively, a corresponding central ERP component at around 220 ms was found; here, a strong correlation between stimulus salience and sex difference of the central ERP component amplitude was observed. Subsequent source analysis revealed increased cortical current densities in right rostral prefrontal (BA 10) and occipital cortex (BA 19) in female subjects. This is the first study to report on a tripartite association between sex differences in ERPs, visual stimulus salience, and right prefrontal cortex activation during attentional processing.

Attention network test (ANT) reveals gender-specific alterations of executive function in schizophrenia

The Attention Network Test (ANT) provides measures for three different components of visual attention: executive control (=conflict inhibition), orienting, and alerting. There is reasonable evidence that alterations of attention-mainly in the executive/conflict domain-are associated with susceptibility to psychiatric illness. Specific impairments may be a characteristic for a medical condition such as schizophrenia and thus shift our understanding from a neuropsychological endophenotype to a more precise genetic understanding of this disorder. Study subjects comprised 35 schizophrenic patients and 35 healthy controls (13 female and 22 male in both groups). The ANT was administered to all participants and rated individual responses for the three factors (alerting, orienting, and conflict) and their respective ratios relative to mean reaction times. With regard to gender differences, group comparisons were performed for schizophrenic patients vs. healthy controls. Significant differences between patients and controls could be detected for mean reaction time (639 vs. 538 ms) and for conflict ratio (0.158 vs. 0.191). The latter difference mainly resulted from gender-specific variances of the conflict network in opposite directions. The executive function as represented by the conflict network of visual attention of the ANT is affected in schizophrenia. We have detected hitherto unreported gender-specific differences between healthy controls and schizophrenic patients. Especially as regards the conflict network, the ANT offers a promising methodology to detect a neuropsychological endophenotype of schizophrenia.

COMT Val 158 Met polymorphism is associated with cognitive flexibility in a signal discrimination task in schizophrenia

BACKGROUND

Associations between the well-known functional single nucleotide polymorphism Val (158)Met in the gene encoding catechol- O-methyltransferase (COMT) and cognitive do-mains affected in schizophrenia are inconsistent regarding directionality and specific impact and call for a more fundamental cognitive endophenotype. Recent studies suggest that the COMT genotype contributes to cognitive flexibility, a fundamental cognitive ability that potentially influences an individual's performance in a variety of other neurocognitive tasks.

METHODS

We investigated the association between COMT Val (158)Met genotype and cognitive flexibility as assessed by signal discrimination in the Continuous Performance Test - Identical Pairs version in a cohort of 111 German schizophrenic patients.

RESULTS

COMT genotype was significantly associated with signal discrimination index d' in schizophrenia. The Val/Val genotype was associated with the highest and the Met/Met genotype with the lowest scores; heterozygous individuals displayed an intermediate performance.

CONCLUSIONS

Our data suggest that allelic variation at the COMT Val (158)Met locus may influence signal discrimination capacity in schizophrenia and confirm that Val loading, probably due to decreased prefrontal dopamine availability, is associated with greater cognitive flexibility, which in turn may influence other cognitive measures that have been associated with COMT to date.

Executive attention in schizophrenic males and the impact of COMT Val108/158Met genotype on performance on the attention network test

BACKGROUND

Executive control of attention in schizophrenia has recently been assessed by means of the Attention Network Test (ANT). In the past, for tasks assessing executive attention, findings in schizophrenia have been contradictory, among others suggesting a lack of increased stimulus interference effects. Attention and executive functioning are substantially influenced by candidate genes of schizophrenia, including the functional single-nucleotide polymorphism catechol-o-methyltransferase (COMT) Val108/158Met, with task-dependent, specific effects of Met allele load on cognitive function. Therefore, we aimed at investigating executive attention in schizophrenic patients (SZP) as compared with healthy controls (HC), and to assess the specific impact of COMT Val108/158Met on executive attention, using ANT.

METHODS

We applied ANT to 63 SZP and 40 HC. We calculated a general linear model to investigate the influence of affection status and the COMT Val108/158Met genotype on executive attention as assessed by the ANT.

RESULTS

Multivariate analysis of variance revealed a significant effect of group on executive attention. SZP exhibited smaller conflict effects in the ANT. Met allele load significantly modulated executive attention efficiency, with homozygous Met individuals showing low overall reaction time but increased effects conflicting stimulus information in executive attention.

CONCLUSIONS

Our data suggest a disease-related dissociation of executive attention with reduced conflict effects in SZP. Furthermore, they support the hypothesis of differential tonic-phasic dopamine activation and specific dopamine level effects in different cognitive tasks, which helps interpreting contradictory findings of Met allele load on cognitive performance. Disease status seems to modulate the impact of COMT Val108/158Met on cognitive performance.

Clozapine-induced agranulocytosis and its genetic determinants

Clozapine-induced agranulocytosis (CiA) is a potentially life-threatening pharmacological adverse drug reaction, which limits a broader application of this highly effective atypical antipsychotic in schizophrenic patients. Although this adverse reaction has been well known for almost 30 years, only few genetically based determinants can be identified to date. Furthermore, owing to rare occurrence, specific clinical course and complexity of pathomechanisms of antipsychotic-induced agranulocytosis, only a few of the findings met the criteria of replication. The most promising susceptibility genes for CiA include genes involved in the human leukocyte antigen system and in specific metabolizing enzyme systems. However, complex idiosyncratic drug reactions such as CiA are considered to be determined by multiple, possibly interacting genetic variations, rather than by a single causative variant.