Executive control in schizophrenia: a preliminary study on the moderating role of COMT Val158Met for comorbid alcohol and substance use disorders

Gender divergent effect of COMT gene rs4680 polymorphism on the association between executive dysfunction and psychotic-like experiences

AIM

Premorbid cognitive impairments are observed prior to the onset of schizophrenia. Catechol-O-methyltransferase (COMT) rs4680 is associated with psychosis and plays a crucial role in the development of the executive function. In addition, genetic COMT variations and gender affect its enzymatic activity. Therefore, the aim of this study was to evaluate the impact of COMT rs4680 on the relationship between executive dysfunction and psychotic-like experiences (PLEs) in college students, with the additional investigation of the gender difference.

METHODS

A total of 463 students provided biological samples for DNA analysis and the COMT gene rs4680 polymorphism was discriminated by the improved multiplex ligase detection reaction method. They also completed the Prodromal Questionnaire and the Dysexecutive Questionnaire.

RESULTS

Executive dysfunction significantly predicted positive PLEs in the total, male and female population (β = 0.515, 0.508 and 0.512, p < 0.001). The results of moderated analysis revealed that COMT rs4680 recessive genetic model ('AA genotype' versus 'G carrier') moderated the relationship between executive dysfunction and psychotic-like experience in the total and females (p = 0.002 and p <0.001, respectively), but not in males.

CONCLUSION

These findings revealed a female-specific effect of COMT rs4680 on the relationship between executive dysfunction and PLEs in young adults.

Identification of 34 genes conferring genetic and pharmacological risk for the comorbidity of schizophrenia and smoking behaviors

The prevalence of smoking is significantly higher in persons with schizophrenia (SCZ) than in the general population. However, the biological mechanisms of the comorbidity of smoking and SCZ are largely unknown. This study aimed to reveal shared biological pathways for the two diseases by analyzing data from two genome-wide association studies with a total sample size of 153,898. With pathway-based analysis, we first discovered 18 significantly enriched pathways shared by SCZ and smoking, which were classified into five groups: postsynaptic density, cadherin binding, dendritic spine, long-term depression, and axon guidance. Then, by using an integrative analysis of genetic, epigenetic, and expression data, we found not only 34 critical genes (e.g., PRKCZ, ARHGEF3, and CDKN1A) but also various risk-associated SNPs in these genes, which convey susceptibility to the comorbidity of the two disorders. Finally, using both in vivo and in vitro data, we demonstrated that the expression profiles of the 34 genes were significantly altered by multiple psychotropic drugs. Together, this multi-omics study not only reveals target genes for new drugs to treat SCZ but also reveals new insights into the shared genetic vulnerabilities of SCZ and smoking behaviors.

FOXP2 contributes to the cognitive impairment in chronic patients with schizophrenia

The forkhead-box P2 (FOXP2), involving in language and memory function, has been identified as susceptibility to schizophrenia. However, no study examined the role of FOXP2 on cognitive impairment in schizophrenia. Total 1106 inpatients with schizophrenia and 404 controls were recruited and genotyped. Among them, 867 patients and 402 controls were assessed through the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). SHEsis software was used to investigate the association of FOXP2 rs10447760 with schizophrenia, followed by logistic regression. The model of covariance (ANCOVA) and multivariate analysis were conducted to investigate the effect of FOXP2 rs10447760 on cognitive impairment in schizophrenia. No differences in the genotypic and allelic frequencies of the FOXP2 rs10447760 were found between patients and controls (both p> 0.05). Except for the visuospatial/constructional score (p > 0.05), other five RBANS scores were lower in patients compared to controls (all p < 0.0001). Interestingly, we found immediate memory score was lower in patients carrying genotype CT compared to genotype CC (F=5.19, p=0.02), adjusting for confounding data. Our study suggested that FOXP2 rs10447760 has no effect on the susceptibility to schizophrenia, while it may be associated with its cognitive impairment, especially immediate memory in chronic schizophrenia.

Facial emotion recognition in schizophrenia: An exploratory study on the role of comorbid alcohol and substance use disorders and COMT Val158Met

OBJECTIVES

To explore whether facial emotion recognition (FER), impaired in both schizophrenia and alcohol and substance use disorders (AUDs/SUDs), is additionally compromised among comorbid subjects, also considering the role of catechol-O-methyltransferase (COMT) Val158Met.

METHODS

We conducted a cross-sectional study, randomly recruiting 67 subjects with a DSM-IV-TR diagnosis of schizophrenia, and rigorously assessing AUDs/SUDs and COMT Val158Met polymorphism. FER was assessed using the Ekman 60 Faces Test- EK-60F.

RESULTS

As a whole, the sample scored significantly lower than normative data on EK-60F. However, subjects with comorbid AUDs/SUDs did not perform worse on EK-60F than those without, who had a better performance on EK-60F if they carried the COMT Val/Met variant.

CONCLUSIONS

This study is the first to date examining the impact of AUDs/SUDs and COMT variants on FER in an epidemiologically representative sample of subjects with schizophrenia. Our findings do not suggest an additional impairment from comorbid AUDs/SUDs on FER among subjects with schizophrenia, whilst COMT Val158Met, though based on a limited sample, might have a role just among those without AUDs/SUDs. Based on our results, additional research is needed also exploring differential roles of various substances.