Background: The polymorphism rs6313 (T102C) has been associated with suicidal behavior in case–control and meta-analysis studies, but results and conclusions remain controversial. The aim of the present study was to examine the association between T102C with suicidal behavior in a case–control study and, to assess the combined evidence – this case–control study and available data from other related studies – we carried out a meta-analysis.Methods: We conducted a case–control study that included 161 patients with suicide attempts and 244 controls; we then performed a meta-analysis. The following models were evaluated in the meta-analysis: A) C allele vs T allele; B) T allele vs C allele; C) Caucasian population, D) Asian population, and E) suicide attempters with schizophrenia.Results: We found an association between attempted suicide and control participants for genotype (χ2=6.28, p=0.04, df=2) and allele (χ2=6.17, p=0.01, df=1, OR 1.48 95% IC: 1.08-2.03) frequencies in the case–control study. The meta-analysis, comprising 23 association studies (including the present one), showed that the rs6313 polymorphism is not associated with suicidal behavior for the following comparisons:T allele vs C allele (OR: 1.03; 95% CI 0.93-1.13; p(Z)=0.44); C allele vs T allele: (OR:0.99; 95% CI: 0.90-1.08; p(Z)=0.22); Caucasians (OR:1.09; 95% CI: 0.96-1.23), and Asians (OR:0.96; 95% CI: 0.84-1.09).Conclusion: Our results showed association between the rs6313 (T102C) polymorphism and suicidal behavior in the case–control study. However, the meta-analysis showed no evidence of association. Therefore, more studies are necessary to determine conclusively an association between T102C and suicidal behavior.

The association between the dopamine D2 receptor (DRD2) gene and schizophrenia has been studied though no conclusive outcomes have been attained. The aim of this study was to perform a systematic review and meta-analysis to explore the relation between three polymorphisms of the DRD2 gene (C957T, TaqI and Ser311Cys) and schizophrenia. The search was made in PubMed and EBSCO databases (up to February 2016). The systematic review included 34 case–control association studies (34 for C957T, 16 for TaqI and 36 for Ser311Cys). The association analysis comprised the allelic, additive, dominant, and recessive genetic models. The meta-analysis was performed following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. The meta-analysis showed that TaqI (additive model: OR 0.57, 95% CI 0.30–1.14) and C957T (additive model: OR 0.75, 95% OR 0.58–0.97, recessive model: OR 0.79, 95% CI 0.64–0.98) exert a protective effect against developing schizophrenia. However, the sub-analysis for the C957T variant showed that this polymorphism exhibits a risk factor effect on Chinese individuals (allelic model: OR 1.33, 95% CI 1.04–1.70). Our meta-analysis suggests an association of the DRD2 gene and the risk for schizophrenia, given that TaqI and C957T polymorphisms presented a protective effect against schizophrenia, and in the sub-analyses the C957T variant increased the risk for this disorder in the Chinese population.

The COVID-19 pandemic has had an impact on mental health in the general population, but no systematic synthesis of evidence of this effect has been undertaken for the Mexican population. Relevant studies were identified through the systematic search in five databases until December, 2021. The selection of studies and the evaluation of their methodological quality were performed in pairs. The Newcastle-Ottawa Scale (NOS) was used for study quality appraisal. The protocol of this systematic review was registered with PROSPERO (protocol ID: CRD42021278868). This review included 15 studies, which ranged from 252 to 9361 participants, with a total of 26,799 participants. The findings show that COVID-19 has an impact on the Mexican population’s mental health and is particularly associated with anxiety, depression, stress and distress. Females and younger age are risk factors for development mental health symptoms. Mitigating the negative effects of COVID-19 on mental health should be a public health priority in Mexico.

Background: individuals with type 2 diabetes show emotional distress as they learn how to cope with the disease. The emotional distress increases the possibility of complications in these patients. The aims of the present study were to evaluate the impact of the emotional distress in the quality of life of individuals with diabetes, and to investigate the demographic and clinical characteristics associated with the emotional distress of living with diabetes in a Mexican population. Methods: a total of 422 Mexican individuals with type 2 diabetes were recruited from the outpatient Diabetes Clinic of the Hospital Regional de Alta Especialidad Dr. Gustavo A. Rovirosa of Villahermosa, Tabasco. Demographic and clinical characteristics along with quality of life (SF-36) were assessed in these individuals. The emotional distress of living with diabetes was measured using the 5-item Problem Areas in Diabetes. Patients were divided according to the presence of high or low distress. Results: we identified that 31.8% (n = 134) of patients presented high diabetes-related emotional distress. We observed that hepatic diseases as comorbidities (p = 0.008) and diagnosis of major depression (p = 0.04) are factors associated with the emotional distress of living with diabetes. These patients showed a reduced quality of life in all dimensions (p < 0.001); the most affected dimensions were physical role (d = 0.37) and general health (d = 0.89) showing lower scores in comparison with patients with low emotional distress. Conclusions: our results suggest that Mexican individuals with type 2 diabetes mellitus show high emotional distress living with the disease and have a decreased quality of life. Therefore, it is necessary to decrease factors associated with the high emotional distress of living with diabetes in patients with type 2 diabetes.

The polymorphism COMTval158met has been associated with suicidal behavior in case-control and meta-analysis studies, but results and conclusions remain controversial. The objective of this study was to examine the association between COMT val158met with suicidal behavior in a case-control study and to assess the combined evidence -this case-control study and available data from other related studies- we carried out a meta-analysis. We conducted a case-control study with 105 patients with suicide attempts and 236 controls. Subsequently, we performed a meta-analysis of published genetic association studies by searching through Medline, PubMed and Web of Science databases. No significant differences were found in the distribution of alleles (χ2 = 0.33, 1 df, p = 0.56) or genotypes (χ2 = 2.36, 2 df, p = 0.26). The meta-analysis comprising 12 association studies (including the present one) showed that the risk COMTmet allele of COMTval158/met is not associated with suicidal behavior (OR: 1.09, 95% CI: 0.97-1.23), even in the absence of heterogeneity (OR: 1.09, 95% CI: 0.97-1.23). Our results showed no association between COMTval158/met and suicidal behavior. However, more studies are necessary to determine conclusively an association between COMT and suicidal behavior.