Shifting the paradigm of social withdrawal: a new era of coexisting pathological and non-pathological hikikomori.

PURPOSE OF REVIEW: Social withdrawal syndrome, known as "hikikomori," has been highlighted since the late 1990 s in Japan. Hikikomori is more common in urban areas, and often comorbid with mental disorders, and now spreading throughout the world. In the post-COVID-19 era, not outing is no longer considered pathological in itself as the "new normal," and a novel concept of hikikomori is needed. This review summarizes the concept of hikikomori, and presents the latest methods for identification of hikikomori. RECENT FINDINGS: The novel definition can distinguish between pathological and non-pathological hikikomori using the scale of "Hikikomori Diagnostic Evaluation (HiDE)," which has been developed in the hikikomori research lab at Kyushu University. An online survey among non-working adults has revealed that persons who have become pathological hikikomori for less than three months showed a particularly strong tendency toward gaming disorder and depression. SUMMARY: Now, physical isolation itself is not pathological, but when dysfunction and distress are present, rapid mental health support should be provided. In the novel urban society, the establishment of a checkup system to assess whether persons who stay home are happy or suffering is important for prevention against mental disorders triggered by social isolation.

Pharmacoepidemiology and Clinical Correlates of Lithium Treatment for Bipolar Disorder in Asia.

BACKGROUND: As clinical practices with lithium salts for patients diagnosed with bipolar disorder (BD) are poorly documented in Asia, we studied the prevalence and clinical correlates of lithium use there to support international comparisons. METHODS: We conducted a cross-sectional study of use and dosing of lithium salts for BD patients across 13 Asian sites and evaluated bivariate relationships of lithium treatment with clinical correlates followed by multivariate logistic regression modeling. RESULTS: In a total of 2139 BD participants (52.3% women) of mean age 42.4 years, lithium salts were prescribed in 27.3% of cases overall, varying among regions from 3.20% to 59.5%. Associated with lithium treatment were male sex, presence of euthymia or mild depression, and a history of seasonal mood change. Other mood stabilizers usually were given with lithium, often at relatively high doses. Lithium use was associated with newly emerging and dose-dependent risk of tremors as well as risk of hypothyroidism. We found no significant differences in rates of clinical remission or of suicidal behavior if treatment included lithium or not. CONCLUSIONS: Study findings clarify current prevalence, dosing, and clinical correlates of lithium treatment for BD in Asia. This information should support clinical decision-making regarding treatment of BD patients and international comparisons of therapeutic practices.

Clinical use of mood stabilizers beyond treatment for bipolar disorder: The REAP-MS study.

OBJECTIVE: Mood stabilizers are psychotropic drugs mainly used to treat bipolar disorder in the acute phase or for maintenance therapy to prevent relapse. In clinical practice, mood stabilizers are commonly prescribed for conditions other than bipolar disorder. This study investigated the distribution of mood stabilizer prescriptions for different psychiatric diagnoses and studied differences in the drugs, dosage, and plasma concentration in 10 Asian countries including Taiwan, South Korea, Malaysia, China, Thailand, India, Pakistan, Singapore, Indonesia, and Myanmar. METHODS: Patients prescribed mood stabilizers (lithium, carbamazepine, valproic acid, or lamotrigine) for a psychiatric condition other than bipolar disorder (codes F31.0-F31.9 in the International Classification of Diseases, 10th Edition, Clinical Modification) were recruited through convenience sampling. A website-based data entry system was used for data collection. RESULTS: In total, 1557 psychiatric patients were enrolled. Schizophrenia, schizotypal, delusional, and other non-mood psychotic disorders (F20-F29, 55.8 %) was the most common diagnosis, followed by non-bipolar mood disorders (F30, F31- F39, 25.3 %), organic mental disorder (F00-F09, 8.8 %), mental retardation (F70-F79, 5.8 %) and anxiety, dissociative, stress-related, somatoform and other nonpsychotic mental disorders (F40-F48, 4.4 %). The most frequently targeted symptoms (>20 %) were irritability (48 %), impulsivity (32.4 %), aggression (29.2 %), anger (20.8 %), and psychosis (24.1 %). Valproic acid was the most frequently used medication. CONCLUSIONS: Clinicians typically prescribe mood stabilizers as empirically supported treatment to manage mood symptoms in patients with diagnoses other than bipolar disorders, though there is on official indication for these disorders. The costs and benefits of this add-on symptomatic treatment warrant further investigation.

Clozapine Use for Bipolar Disorder: An Asian Psychotropic Prescription Patterns Consortium Study.

BACKGROUND: Pharmacoepidemiological studies of clozapine use to treat bipolar disorder (BD), especially in Asia, are rare, although they can provide insights into associated clinical characteristics and support international comparisons of indications and drug dosing. METHODS: We examined the prevalence and clinical correlates of clozapine treatment for BD in 13 Asian countries and regions (China, Hong Kong SAR, India, Indonesia, Japan, Korea, Malaysia, Myanmar, Pakistan, Singapore, Sri Lanka, Taiwan, and Thailand) within an Asian Prescription Patterns Research Consortium. We compared BD patients treated with clozapine or not in initial bivariate comparisons followed by multivariable logistic regression modeling. RESULTS: Clozapine was given to 2.13% of BD patients overall, at a mean daily dose of 275 (confidence interval, 267-282) chlorpromazine-equivalent mg/day. Patients receiving clozapine were older, more likely males, hospitalized, currently manic, and given greater numbers of mood-stabilizing and antipsychotic drugs in addition to clozapine. Logistic regression revealed that older age, male sex, current mania, and greater number of other antipsychotics remained significantly associated with clozapine treatment. Clozapine use was not associated with depressed mood, remission of illness, suicidal risk, or electroconvulsive treatment within the previous 12 months. CONCLUSIONS: The identified associations of clozapine use with particular clinical features call for vigilance in personalized clinical monitoring so as to optimize clinical outcomes of BD patients and to limit risks of adverse effects of polytherapy.

The factor structure of extrapyramidal symptoms evaluated using the Drug-Induced Extrapyramidal Symptoms Scale in patients with schizophrenia: Results from the 2016 REAP AP-4 study.

INTRODUCTION: Drug-induced extrapyramidal syndrome (EPS) remains a major problem in clinical psychiatry. This study aimed to examine the factor structure of drug-induced extrapyramidal symptoms observed in patients with schizophrenia and assessed using the Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS). METHODS: The participants were 1478 patients with a diagnosis of schizophrenia whose EPS was assessed using the DIEPSS in India, Indonesia, Japan, Malaysia, and Taiwan in the 2016 REAP AP-4 study. The records of the participants were randomly divided into two subgroups: the first for exploratory factor analysis of the eight DIEPSS items, and the second for confirmatory factor analysis. RESULTS: The factor analysis identified three factors: F1 (gait and bradykinesia), F2 (muscle rigidity and tremor), and F3 (sialorrhea, akathisia, dystonia, and dyskinesia). CONCLUSION: The results suggest that the eight individual items of the DIEPSS could be composed of three different mechanisms: acute parkinsonism observed during action (F1), acute parkinsonism observed at rest (F2), and central dopaminergic mechanisms with pathophysiology other than acute parkinsonism (F3).

Risk factors of hikikomori among office workers during the COVID-19 pandemic: A prospective online survey.

The global pandemic of COVID-19 has forced people to restrict their outings. In Japan, self-restraint behavior (SRB) has been requested by the government, and some of those decreasing their outings may shift to pathological social withdrawal; hikikomori. The purpose of this study was to examine the risk factors of hikikomori conducting an online prospective survey. An online survey was conducted in June 2020 and December 2020; (1) SRB-related indicators (degree of SRB, motivation for SRB, stigma and self-stigma toward COVID-19, anxiety and depressive feelings toward COVID-19) and (2) general mental health (hikikomori tendency, depressive symptoms, modern type depression (MTD) tendency, internet addiction) were collected. A cross-lagged effects model was performed to examine the association between these variables. Lack of emotional support and lack of socialization in June 2020 increased isolation in December 2020. Besides, MTD and hikikomori interacted with each other. Interestingly, although hikikomori tendency increased depressive tendencies, SRB itself did not have a significant path on any mental health-related variables. Poor interpersonal relationships, rather than SRB per se, are suggested to be a risk factor for increased isolation among office workers in the COVID-19 pandemic. Appropriate early interventions such as interpersonal or emotional support may prevent the transition to pathological hikikomori. The association between MTD and hikikomori seems to reveal the interesting possibility that MTD is a gateway to increased risk of hikikomori, and that hikikomori is a gateway to MTD as well. Future research is required to elucidate the relationship between hikikomori and MTD.

A Machine-Learning-Algorithm-Based Prediction Model for Psychotic Symptoms in Patients with Depressive Disorder.

Psychotic symptoms are rarely concurrent with the clinical manifestations of depression. Additionally, whether psychotic major depression is a subtype of major depression or a clinical syndrome distinct from non-psychotic major depression remains controversial. Using data from the Research on Asian Psychotropic Prescription Patterns for Antidepressants, we developed a machine-learning-algorithm-based prediction model for concurrent psychotic symptoms in patients with depressive disorders. The advantages of machine learning algorithms include the easy identification of trends and patterns, handling of multi-dimensional and multi-faceted data, and wide application. Among 1171 patients with depressive disorders, those with psychotic symptoms were characterized by significantly higher rates of depressed mood, loss of interest and enjoyment, reduced energy and diminished activity, reduced self-esteem and self-confidence, ideas of guilt and unworthiness, psychomotor agitation or retardation, disturbed sleep, diminished appetite, and greater proportions of moderate and severe degrees of depression compared to patients without psychotic symptoms. The area under the curve was 0.823. The overall accuracy was 0.931 (95% confidence interval: 0.897-0.956). Severe depression (degree of depression) was the most important variable in the prediction model, followed by diminished appetite, subthreshold (degree of depression), ideas or acts of self-harm or suicide, outpatient status, age, psychomotor retardation or agitation, and others. In conclusion, the machine-learning-based model predicted concurrent psychotic symptoms in patients with major depression in connection with the "severity psychosis" hypothesis.

Network analysis of psychiatric symptoms in schizophrenia: Findings from the Research on Asian Psychotropic Prescription Patterns for Antipsychotics (REAP-AP).

AIMS: Schizophrenia is a major mental disorder with a wide range of psychiatric symptoms. This study explored the structure of psychiatric symptoms of schizophrenia using network analysis in a large representative Asian sample based on a survey of clinical features and treatment used in schizophrenia patients across 15 countries/territories in Asia. METHODS: Data on the demographic characteristics and psychiatric symptoms in schizophrenia patients were extracted from the dataset of the fourth Research on Asia Psychotropic Prescription for Antipsychotics (REAP-AP) project. The presence of the following psychiatric symptoms including delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, negative symptoms, social/occupational dysfunction, verbal aggression, physical aggression, and affective symptoms were analyzed. RESULTS: A total of 3681 patients were included. The network analysis revealed that verbal aggression, hallucinations, and social/occupational dysfunction were the most central symptoms, while the connections between social/occupational dysfunction and verbal aggression, and between hallucinations and disorganized speech were the two strongest edges. There were significant gender differences in the network structure based on the network structure invariance test (M=0.74, P = 0.03) and invariant edge strength test. The positive correlation between verbal aggression and hallucinations was significantly stronger in the female network than that in the male network (P = 0.03), while a negative correlation between affective symptoms and negative symptoms was found in the female, but not the male network (P < 0.01). CONCLUSION: Central symptoms including verbal aggression, hallucinations, and socio-occupational dysfunction should be addressed in developing targeted treatment strategy for schizophrenia patients.

Machine Learning Algorithm-Based Prediction Model for the Augmented Use of Clozapine with Electroconvulsive Therapy in Patients with Schizophrenia.

The augmentation of clozapine with electroconvulsive therapy (ECT) has been an optimal treatment option for patients with treatment- or clozapine-resistant schizophrenia. Using data from the Research on Asian Psychotropic Prescription Patterns for Antipsychotics survey, which was the largest international psychiatry research collaboration in Asia, our study aimed to develop a machine learning algorithm-based substantial prediction model for the augmented use of clozapine with ECT in patients with schizophrenia in terms of precision medicine. A random forest model and least absolute shrinkage and selection operator (LASSO) model were used to develop a substantial prediction model for the augmented use of clozapine with ECT. Among the 3744 Asian patients with schizophrenia, those treated with a combination of clozapine and ECT were characterized by significantly greater proportions of females and inpatients, a longer duration of illness, and a greater prevalence of negative symptoms and social or occupational dysfunction than those not treated. In the random forest model, the area under the curve (AUC), which was the most preferred indicator of the prediction model, was 0.774. The overall accuracy was 0.817 (95% confidence interval, 0.793−0.839). Inpatient status was the most important variable in the substantial prediction model, followed by BMI, age, social or occupational dysfunction, persistent symptoms, illness duration > 20 years, and others. Furthermore, the AUC and overall accuracy of the LASSO model were 0.831 and 0.644 (95% CI, 0.615−0.672), respectively. Despite the subtle differences in both AUC and overall accuracy of the random forest model and LASSO model, the important variables were commonly shared by the two models. Using the machine learning algorithm, our findings allow the development of a substantial prediction model for the augmented use of clozapine with ECT in Asian patients with schizophrenia. This substantial prediction model can support further studies to develop a substantial prediction model for the augmented use of clozapine with ECT in patients with schizophrenia in a strict epidemiological context.

Dosing of Mood Stabilizers for Bipolar Disorder Patients in the Research on Asian Psychotropic Prescription Patterns Consortium Study.

BACKGROUND: Because use and dosing of mood stabilizers (MSs) to treat bipolar disorder (BD) patients in Asia are not well documented, we examined prevalence and clinical correlates of treatment of Asian BD patients with relatively high doses of MSs. METHODS: We conducted a pharmacoepidemiological survey across 13 Asian countries and territory in the Research on Asian Psychotropic Prescription Patterns Consortium. Mood stabilizer doses were converted to lithium carbonate equivalents (Li-eq milligrams per day). We compared relatively high (>900 Li-eq mg/day) versus lower MS doses by bivariate comparisons, followed by multivariable linear regression to identify factors associated with higher MS doses. RESULTS: Among 1647 participants, MS dose averaged 584 (confidence interval, 565-603 Li-eq mg/d). Preliminarily, the 13.1% of the subjects given greater than 900 mg/d versus those given lower doses were younger, male, currently hospitalized, not currently depressed, and reported lifetime suicidal ideation; they also received relatively high doses of antipsychotics, received electroconvulsive treatment within the previous 12 months, and had greater ratings of tremors and sedation. By linear regression modeling, the mean proportion given high doses of MS was associated significantly and independently with higher doses of antipsychotics, younger age, male sex, hospitalized, more years of illness, country, higher body mass index, recent electroconvulsive treatment, and being in illness remission. CONCLUSIONS: Relatively high doses of MSs for BD are prevalent, but vary markedly among Asian countries, and are particularly likely among young males, ill for many years, and given high doses of antipsychotics or ECT. These characteristics allow better identification of patient profiles that can guide treatment of BD patients.

Network Analysis-Based Disentanglement of the Symptom Heterogeneity in Asian Patients with Schizophrenia: Findings from the Research on Asian Psychotropic Prescription Patterns for Antipsychotics.

The symptom heterogeneity of schizophrenia is consistent with Wittgenstein's analogy of a language game. From the perspective of precision medicine, this study aimed to estimate the symptom presentation and identify the psychonectome in Asian patients, using data obtained from the Research on Asian Psychotropic Prescription Patterns for Antipsychotics. We constructed a network structure of the Brief Psychiatric Rating Scale (BPRS) items in 1438 Asian patients with schizophrenia. Furthermore, all the BPRS items were considered to be an ordered categorical variable ranging in value from 1-7. Motor retardation was situated most centrally within the BPRS network structure, followed by depressive mood and unusual thought content. Contrastingly, hallucinatory behavior was situated least centrally within the network structure. Using a community detection algorithm, the BPRS items were organized into positive, negative, and general symptom clusters. Overall, DSM symptoms were not more central than non-DSM symptoms within the symptom network of Asian patients with schizophrenia. Thus, motor retardation, which results from the unmet needs associated with current antipsychotic medications for schizophrenia, may be a tailored treatment target for Asian patients with schizophrenia. Based on these findings, targeting non-dopamine systems (glutamate, γ-aminobutyric acid) may represent an effective strategy with respect to precision medicine for psychosis.

Prescription Patterns for Bipolar Disorder in Asian Countries: Findings from Research on Asian Prescription Pattern-Bipolar Disorder.

OBJECTIVE: Pharmacotherapy including mood stabilizers and antipsychotics are frequently used in bipolar disorder (BD); however, the lack of consensus regarding the definition of polypharmacy hinders conducting comparative studies across different settings and countries. Research on Asian Prescription Pattern (REAP) is the largest and the longest lasting international collaborative research in psychiatry in Asia. The objective of REAP BD was to investigate the prescription patterns of psychotropic medications across Asian countries. The rates of polypharmacy and psychotropic drug load were also analyzed. METHODS: The data collection was web-based. Prescription patterns were categorized as (1) mood stabilizer monotherapy: one mood stabilizer; (2) antipsychotic monotherapy: one antipsychotic; (3) simple polypharmacy: one mood stabilizer and one antipsychotic; and (4) complex polypharmacy: ≥ 2 mood stabilizers or/and antipsychotics. The psychotropic drug load in each patient was calculated using the defined daily dose method. RESULTS: Among 2003 patients with BD (52.1% female, 42.4 years) from 12 countries, 1,619 (80.8%) patients received mood stabilizers, 1,644 (82.14%) received antipsychotics, and 424 (21.2%) received antidepressants, with 14.7% mood stabilizer monotherapy, 13.4% antipsychotic monotherapy, 48.9% simple polypharmacy, 20.3% complex polypharmacy, and 2.6% other therapy. The average psychotropic drug load was 2.05 ± 1.40. Results varied widely between countries. CONCLUSION: Over 70% of psychotropic regimens involved polypharmacy, which accords with the high prevalence of polypharmacy in BD under a permissive criterion (2 or more core psychotropic drugs) worldwide. Notably, ≥ 80% of our sample received antipsychotics, which may indicate an increasing trend in antipsychotic use for BD treatment.

Analysis of the trends of polypharmacy and high-dose prescriptions in Japan.

INTRODUCTION: After extensive research, this study explored whether high-dose prescriptions and polypharmacy remain more frequent in Japan than elsewhere. If confirmed, we aimed to identify the factors that contributed to this unique trend. METHODS: The psychotropic drug prescription patterns for patients with schizophrenia in Japan were reviewed. This was based on a large sample collected from surveys of the Research on Asian Psychotropic Prescription Patterns, an international collaborative research project conducted by Asian psychiatrists to monitor prescriptions of psychotropic drugs for people with mental disorders, in 2001, 2004, 2008, and 2016. RESULTS: The 2016 Research on Asian Psychotropic Prescription Patterns survey revealed that Japan continued to demonstrate the highest rate of polypharmacy and the highest dosages of psychotropic prescription drugs for patients with schizophrenia among the 15 countries and areas that participated in the survey. DISCUSSION: The Research on Asian Psychotropic Prescription Patterns surveys demonstrated that science plays a limited role in the decision-making process for prescriptions of psychotropic medications. Such prescriptions are influenced by a wide range of factors, such as the national mental health policy, prescription-financing systems, the history of psychiatry in each country, and the prevailing culture. Hospital-based national mental health policies and mental health financing systems have been the primary obstacles to reducing polypharmacy in Japan.

A Call for a Rational Polypharmacy Policy: International Insights From Psychiatrists.

OBJECTIVE: Recently, rational polypharmacy approaches have been proposed, regardless of the lower risk and cost of monotherapy. Considering monotherapy as first-line treatment and polypharmacy as rational treatment, a balanced attitude toward polypharmacy is recommended. However, the high prevalence of polypharmacy led the Japanese government to establish a polypharmacy reduction policy. Based on this, the association between the policy and psychiatrists' attitude toward polypharmacy has been under debate. METHODS: We developed an original questionnaire about Psychiatrists' attitudes toward polypharmacy (PAP). We compared the PAP scores with the treatment decision-making in clinical case vignettes. Multiple regression analyses were performed to quantify associations of explanatory variables including policy factors and PAP scores. The anonymous questionnaires were administered to psychiatrists worldwide. RESULTS: The study included 347 psychiatrists from 34 countries. Decision-making toward polypharmacy was associated with high PAP scores. Multiple regression analysis revealed that low PAP scores were associated with the policy factor (ß=-0.20, p=0.004). The culture in Korea was associated with high PAP scores (ß=0.34, p<0.001), whereas the culture in India and Nepal were associated with low scores (ß=-0.15, p=0.01, and ß=-0.17, p=0.006, respectively). CONCLUSION: Policy on polypharmacy may influence psychiatrists' decision-making. Thus, policies considering rational polypharmacy should be established.

Dyskinesia is most centrally situated in an estimated network of extrapyramidal syndrome in Asian patients with schizophrenia: findings from research on Asian psychotropic prescription patterns for antipsychotics.

BACKGROUND: Network analysis provides a new viewpoint that explicates intertwined and interrelated symptoms into dynamic causal architectures of symptom clusters. This is a process called 'symptomics' and is concurrently applied to various areas of symptomatology. AIMS: Using the data from Research on Asian Psychotropic Prescription Patterns for Antipsychotics (REAP-AP), we aimed to estimate a network model of extrapyramidal syndrome in patients with schizophrenia. METHODS: Using data from REAP-AP, extrapyramidal symptoms of 1046 Asian patients with schizophrenia were evaluated using the nine items of the Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS). The estimated network of the ordered-categorical DIEPSS items consisted of nodes (symptoms) and edges (interconnections). A community detection algorithm was also used to identify distinctive symptom clusters, and correlation stability coefficients were used to evaluate the centrality stability. RESULTS: An interpretable level of node strength centrality was ensured with a correlation coefficient. An estimated network of extrapyramidal syndrome showed that 26 (72.2%) of all possible 35 edges were estimated to be greater than zero. Dyskinesia was most centrally situated within the estimated network. In addition, earlier antipsychotic-induced extrapyramidal symptoms were divided into three distinctive clusters - extrapyramidal syndrome without parkinsonism, postural instability and gait difficulty-dominant parkinsonism, and tremor-dominant parkinsonism. CONCLUSIONS: Our findings showed that dyskinesia is the most central domain in an estimated network structure of extrapyramidal syndrome in Asian patients with schizophrenia. These findings are consistent with the speculation that acute dystonia, akathisia, and parkinsonism could be the risk factors of tardive dyskinesia.

Coprescription of mood stabilizers in schizophrenia, dosing, and clinical correlates: An international study.

OBJECTIVE: Studies examining coprescription and dosages of mood stabilizers (MSs) with antipsychotics for psychotic disorders are infrequent. Based on sparse extant data and clinical experience, we hypothesized that adjunctive MS use would be associated with certain demographic (e.g., younger age), clinical factors (e.g., longer illness duration), and characteristics of antipsychotic treatment (e.g., multiple or high antipsychotic doses). METHODS: Within an Asian research consortium focusing on pharmaco-epidemiological factors in schizophrenia, we evaluated rates of MS coprescription, including high doses (>1000 mg/day lithium-equivalents) and clinical correlates. RESULTS: Among 3557 subjects diagnosed with schizophrenia in 14 Asian countries, MSs were coprescribed with antipsychotics in 13.6% (n = 485) of the sample, with 10.9% (n = 53) on a high dose. Adjunctive MS treatment was associated (all p < 0.005) with demographic (female sex and younger age), setting (country and hospitalization), illness (longer duration, more hospitalizations, non-remission of illness, behavioral disorganization, aggression, affective symptoms, and social-occupational dysfunction), and treatment-related factors (higher antipsychotic dose, multiple antipsychotics, higher body mass index, and greater sedation). Patients given high doses of MSs had a less favorable illness course, more behavioral disorganization, poorer functioning, and higher antipsychotic doses. CONCLUSIONS: Schizophrenia patients receiving adjunctive MS treatment in Asian psychiatric centers are more severely ill and less responsive to simpler treatment regimens.

QT interval prolongation noted in one percent of 2553 Asian patients with schizophrenia: Findings from the REAP-AP survey.

Although the association between antipsychotic use and corrected QT interval (QTc) prolongation has been repeatedly confirmed, the relationship has been rarely studied in a practical setting. Using data from the Research on Asian Psychotropic Prescription Patterns for Antipsychotics (REAP-AP) survey, our study aimed to investigate the prevalence and clinical correlates of QTc prolongation in 2553 Asian patients with schizophrenia. After adjusting for the potential effect of confounding factors, the baseline and clinical characteristics of the schizophrenia patients with and without QTc prolongation were compared using analyses of covariance and binary logistic analyses. In addition, a binary logistic analysis model with a forward selection method was used to identify the distinctive clinical correlates of QTc prolongation. QTc prolongation was noted in 1.1% of Asian patients with schizophrenia. Schizophrenia patients were characterized by lower proportions of disorganized speech and negative symptoms; higher use of amisulpride and clozapine; and higher proportions of rigidity, hypercholesterolemia, and sedation than those without QTc prolongation. Finally, a binary logistic mode showed that amisulpride, clozapine, rigidity, and hypercholesterolemia might be the distinctive clinical correlates of QTc prolongation in Asian patients with schizophrenia. These findings indicate the clinical implications that the uses of amisulpride and clozapine and the occurrences of rigidity and hypercholesterolemia may be potential risk factors for QTc prolongation of schizophrenia patients.

Relationship Between Body Mass Index and Extrapyramidal Symptoms in Asian Patients with Schizophrenia: The Research on Asian Psychotropic Prescription Patterns for Antipsychotics (REAP-AP).

BACKGROUND: Although an inverse relationship between body mass index (BMI) and Parkinson disease (PD) has been repeatedly reported, to our knowledge, the relationship between BMI and antipsychotic-induced extrapyramidal symptoms (EPS) has rarely been studied in patients with schizophrenia. Our study aimed to evaluate the relationship between BMI and EPS in patients with schizophrenia. SUBJECTS AND METHODS: Using data from the Research on Asian Psychotropic Prescription Patterns for Antipsychotics (REAP-AP) study, we compared the prevalence of EPS in 1448 schizophrenia patients stratified as underweight, normal range, overweight pre-obese, overweight obese I, overweight obese II, and overweight obese III according to the World Health Organization (WHO) classification system for body weight status, and with underweight, normal range, overweight at risk, overweight obese I, and overweight obese II according to the Asia-Pacific obesity classification. RESULTS: In the first step of the WHO classification system for body weight status, adjusting for the potential effects of confounding factors, the multinomial logistic regression model revealed that underweight was significantly associated with greater rates of bradykinesia and muscle rigidity, and a lower rate of gait disturbance. In the second step of the Asia-Pacific obesity classification, adjusting for the potential effects of confounding factors, the multinomial logistic regression model revealed that underweight was significantly associated with a higher rate of muscle rigidity. CONCLUSION: Findings of the present study consistently revealed that underweight was associated with a greater rate of muscle rigidity in a stepwise pattern among Asian patients with schizophrenia. Although the mechanism underlying the inverse relationship between BMI and muscle rigidity cannot be sufficiently explained, it is speculated that low BMI may contribute to the development of muscle rigidity regardless of antipsychotic "typicality" and dose in patients with schizophrenia.