Schizophrenia Research and Treatment
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Investigating Body Mass Index and Body Composition in Patients with Schizophrenia: A Case-Control Study

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Schizophrenia Research and Treatment publishes original research articles and review articles related to all aspects of schizophrenia.

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Schizophrenia Research and Treatment maintains an Editorial Board of practicing researchers from around the world, to ensure manuscripts are handled by editors who are experts in the field of study.

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Review Article

Cigarette Smoking and Schizophrenia: Etiology, Clinical, Pharmacological, and Treatment Implications

Recent data suggests that the prevalence of smoking in schizophrenia remains high. While reports suggest that smoking increases the risk of developing schizophrenia, the potential causative role of smoking in this relationship needs further investigation. Smokers with schizophrenia are more likely to have more intense positive symptoms and lower cognitive function, but diminished intensity of extrapyramidal side effects than nonsmoking patients with schizophrenia. They were also more likely to exhibit aggressive behaviour compared to nonsmokers, which could suggest higher levels of baseline aggression. The significant cost associated with regular tobacco expenditure can detract from investment in key domains. Large-scale trials have shown that pharmacotherapy for smoking cessation is effective and does not worsen the risk of developing neuropsychiatric symptoms compared to placebo. Electronic cigarette use among schizophrenia patients is high, and there is emerging evidence supportive of its efficacy. Future improvements include large-scale trials assessing the utility, efficacy, and safety of electronic cigarettes in schizophrenia patients.

Research Article

Comparison of Efficacy and Safety between Long-Acting Injectable Antipsychotic Monotherapy and Combination of Long-Acting Injectable and Oral Antipsychotics in Patients with Schizophrenia

Background. Long-acting injectable (LAI) antipsychotics are used as a monotherapy in patients with schizophrenia. However, the combination of LAI and oral antipsychotics is commonly used in clinical practice, despite there being very limited studies investigating the efficacy and safety of this combination compared with LAI antipsychotic monotherapy. Objective. To study the efficacy and safety of LAI antipsychotic monotherapy compared with the combination of LAI and oral antipsychotics in patients with schizophrenia. Methods. This study was a retrospective cohort study, which classified eligible patients into two groups: the LAI antipsychotic monotherapy group and the combination of LAI and oral antipsychotic group. The primary outcome was hospitalization between groups. The duration of the study was 2 years. Results. In total, 86 patients completed the study and were analysed (LAI antipsychotic monotherapy group: ; combination of LAI and oral antipsychotic group: ). There was no significant difference in hospitalization between the two groups (). For other outcomes, there were also no significant differences in both all-cause discontinuation () and adverse drug reactions () between the two groups. Conclusion. The efficacy and safety of LAI antipsychotic monotherapy appeared similar to the combination of LAI and oral antipsychotics in patients with schizophrenia. Therefore, the combination of LAI and oral antipsychotics, which is commonly used in clinical practice, may not be necessary.

Research Article

Homocysteine in Schizophrenia: Independent Pathogenetic Factor with Prooxidant Activity or Integral Marker of Other Biochemical Disturbances?

A wide range of studies have demonstrated that hyperhomocysteinemia is associated with the risk of schizophrenia, but currently available assumptions about the direct involvement of homocysteine (Hcy) in the pathogenesis of schizophrenia are hypothetical. It is possible that in vivo Hcy is only a marker of folate metabolism disturbances (which are involved in methylation processes) and is not a pathogenetic factor per se. Only one study has been conducted in which associations of hyperhomocysteinemia with oxidative stress in schizophrenia (oxidative damage to protein and lipids) have been found, and it has been suggested that the oxidative stress may be induced by the elevated Hcy in schizophrenic patients. But the authors did not study the level of reduced glutathione (GSH), as well as possible causes of hyperhomocysteinemia—disturbances of folate metabolism. The aim of this work is to analyze the association of Hcy levels with the following: (1) redox markers in schizophrenia GSH, markers of oxidative damage of proteins and lipids, and the activity of antioxidant enzymes in blood serum; (2) with the level of folate and cobalamin (В12); and (3) with clinical features of schizophrenia measured using the Positive and Negative Syndrome Scale (PANSS). 50 patients with schizophrenia and 36 healthy volunteers, matched by sex and age, were examined. Hcy in patients is higher than in healthy subjects (), and this may be due to the lower folate level in patients (). In patients, negative correlation was found between the level of Hcy both with the level of folate (, ) and with the level of B12 (, ). At the same time, patients showed higher levels of oxidative modification of serum proteins () and lower catalase (CAT) activity (). However, Hcy is not associated with the studied markers of oxidative stress in patients. In the group of patients with an increased level of Hcy (>10 μmol/l, ) compared with other patients (), some negative symptoms (PANSS) were statistically significantly more pronounced: difficulty in abstract thinking (N5, ), lack of spontaneity and flow in conversation (N6, ), stereotyped thinking (N7, ), and motor retardation (G7, ). Thus, in patients with schizophrenia, hyperhomocysteinemia caused by deficiency of folate and B12 is confirmed and can be considered a marker of disturbances of vitamin metabolism. The redox imbalance is probably not directly related to hyperhomocysteinemia and is hypothetically caused by other pathological processes or by an indirect effect of Hcy, for example, on the enzymatic antioxidant defence system (CAT activity), which requires further exploration. Further study of the role of Hcy in the pathogenesis of schizophrenia is relevant, since the proportion of patients with hyperhomocysteinemia is high and correlations of its level with negative symptoms of schizophrenia are noted.

Research Article

Suicide Behavior and Its Predictors in Patients with Schizophrenia in Ethiopia

Background. People with schizophrenia (PWS) are at greater risk of suicide. However, suicide behaviors that occur in PWS are often overlooked, inadequately characterized, and not consistently integrated into treatment. Despite this burden and consequences in Ethiopia, there is a dearth of studies concerning suicide behavior in PWS. Therefore, this study is aimed at assessing the magnitude of suicide behavior and its predictors among PWS in Ethiopia. Methods. An institution based cross-sectional study was employed. Data were collected using the structured interviewer-administered questionnaire from a sample of 300 PWS at Amanuel Mental Specialized Hospital (AMSH). The revised version of Suicide Behavior Questionnaire (SBQ-R) was used to assess suicide behavior in PWS. The data was collected from March 1 to 30, 2019. Binary logistic regression was performed to identify independent predictors of suicidal behavior at 95% confidence level. Statistical significance was declared at value <0.05. Result. A total of 300 patients with schizophrenia participated in the study. More than two-thirds of 203 (67.7%) of the participants were males, and 116 (38.7%) participants were between the ages of 28 and 37 years. We found that the prevalence of suicide behavior among PWS was 30.3%. Being unemployed (, , 10.05), family history of suicide (, , 7.23), substance use (, , 5.59), current positive psychotic symptoms (hallucination (, , 14.29), and delusion (, , 14.29) and presence of comorbid depression (, , 11.68) were independent significant predictors with suicidal behavior in PWS. Conclusion. The prevalence of suicidal behavior among PWS was found to be high. Hence, designing strategies for early screening and intervention is the most critical prevention strategy of suicide in PWS.

Research Article

Impact of Negative Symptom Domains and Other Clinical Characteristics on Functional Outcomes in Patients with Schizophrenia

Negative symptoms of schizophrenia have generally been defined using five factors; however, few studies have examined the relationship between these five factors and functional outcomes. In addition, there is no definitive conclusion regarding the association between negative symptoms and various aspects of functional outcomes (daily living, social, and vocational). This study is aimed at examining the relationship between these five domains of negative symptoms and different functional outcomes. Patients diagnosed with chronic schizophrenia () were selected for the evaluation. We used the Brief Negative Symptom Scale to assess negative symptoms, the Brief Psychiatric Rating Scale to assess positive symptoms, the Schizophrenia Cognition Rating Scale to assess cognition, and the Evaluative Beliefs Scale (negative self-assessment) to assess psychological factors. We analyzed their relative impact on Social Functioning Scale domains using hierarchical multiple regression analysis. Concerning the relationship between daily living and negative symptoms, cognitive function showed the highest association with residential outcomes, such as self-care and shopping, while avolition appeared to show an additional contribution; however, for recreational outcomes, avolition showed the main association, whereas cognitive function showed no additional contribution. For social outcomes, asociality and negative self-assessment showed the main associations, while vocational outcomes were determined by both cognitive function and multiple negative symptoms, such as avolition, anhedonia, asociality, and alogia. Since negative symptom domains appear to differentially impact each outcome, specifically daily living outcome, it is important to evaluate the residential outcomes and recreational outcomes separately. Overall, the present study points to the importance of formulating psychosocial treatment strategies specific for each type of preferred outcome in patients with schizophrenia.

Research Article

Polygenic Risk Scores for Subtyping of Schizophrenia

Schizophrenia is a complex disorder with many comorbid conditions. In this study, we used polygenic risk scores (PRSs) from schizophrenia and comorbid traits to explore consistent cluster structure in schizophrenia patients. With 10 comorbid traits, we found a stable 4-cluster structure in two datasets (MGS and SSCCS). When the same traits and parameters were applied for the patients in a clinical trial of antipsychotics, the CATIE study, a 5-cluster structure was observed. One of the 4 clusters found in the MGS and SSCCS was further split into two clusters in CATIE, while the other 3 clusters remained unchanged. For the 5 CATIE clusters, we evaluated their association with the changes of clinical symptoms, neurocognitive functions, and laboratory tests between the enrollment baseline and the end of Phase I trial. Class I was found responsive to treatment, with significant reduction for the total, positive, and negative symptoms (, 0.0099, and 0.0028, respectively), and improvement for cognitive functions (VIGILANCE, ; PROCESSING SPEED, ; WORKING MEMORY, ; and REASONING, ). Class II had modest reduction of positive symptoms () and better PROCESSING SPEED (). Class IV had a specific reduction of negative symptoms () and modest cognitive improvement for all tested domains. Interestingly, Class IV was also associated with decreased lymphocyte counts and increased neutrophil counts, an indication of ongoing inflammation or immune dysfunction. In contrast, Classes III and V showed no symptom reduction but a higher level of phosphorus. Overall, our results suggest that PRSs from schizophrenia and comorbid traits can be utilized to classify patients into subtypes with distinctive clinical features. This genetic susceptibility based subtyping may be useful to facilitate more effective treatment and outcome prediction.

Schizophrenia Research and Treatment
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Acceptance rate-
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CiteScore2.700
Journal Citation Indicator0.300
Impact Factor-
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Article of the Year Award: Outstanding research contributions of 2021, as selected by our Chief Editors. Read the winning articles.