The effects of catechol-O-methyltransferase single nucleotide polymorphisms on positive and negative symptoms of schizophrenia: A systematic review and meta-analysis

The catechol-O-methyltransferase (COMT) gene is thought to have an important role in the etiopathogenesis of schizophrenia, but there are conflicting results regarding its role in clinical presentation. We aimed to elucidate the relationship between the single nucleotide polymorphisms (SNPs) in the COMT gene and the severity of positive and negative symptoms. In order to investigate the relationship, the PubMed, PubMed Central, Scopus, and Cochrane CENTRAL databases were screened for eligible articles. Thirty-eight studies, including 4443 adult patients with schizophrenia, were included in the quantitative analyses, and four studies were qualitatively assessed. Quantitative analyses were performed for acutely ill and clinically stable patient subgroups regarding the different genotypes of rs4680 SNP. Our results showed that the severity of negative symptoms was higher in patients who were rs4680 Met homozygous compared to Val/Met heterozygotes only in acutely ill samples. There was no other significant difference between genotypes. Meta-regression did not reveal any significant moderator effect on the difference in negative symptoms. General psychopathology, positive, negative, and total psychotic symptom levels also were similar between Val homozygotes and Met carriers. Nonetheless, there are some limitations in the study. First, SNPs except for rs4680 were under-researched because of the limited number of studies. Second, high heterogeneity across studies was the main concern. Our results suggested that the COMT rs4680 Met allele was associated with higher levels of negative symptoms within acutely ill patients. Future studies should focus on specific patient subgroups to reveal the moderating effects of SNPs

Rate of Overlap between ICD-11 Gaming Disorder and DSM-5 Internet Gaming Disorder along with Turkish Reliability of the Gaming Disorder Scale for Adolescents (GADIS-A)

Introduction: The main aims of the current study were (i) to explore the overlap between Internet gaming disorder (IGD) and gaming disorder (GD) diagnoses, (ii) to identify clinical characteristics in clinical settings, and (iii) to measure psychometric properties of the Gaming Disorder Scale for Adolescents (GADIS-A). Methods: 222 adolescents who were followed up within a tertiary-care mental health hospital, were included (IGD/GD group [n = 111], clinical comparison group [n = 90], healthy controls [n = 21]). The tools used were the GADIS-A, Internet Gaming Disorder Scale - Short-Form, The Difficulties in Emotion Regulation Scale (DERS-36), Children's Global Assessment Scale, and a semistructured interview for DSM-5 diagnoses. Results: The overlap rate of IGD and GD is 73%. Comorbid ADHD diagnoses were more commonly found in the IGD group compared to the clinical comparison group. Patients who met GD and IGD diagnoses revealed higher scores in DERS-36. Turkish GADIS-A Item-total score correlation coefficients were between 0.627 and 0.860. In the sample, there was a high level of correlation between the number of DSM-5 and ICD-11 diagnostic criteria met and GADIS-A scale scores. The Cronbach's alphas if item deleted ranged between 0.942 and 0.954. In addition, treatment refusal was more frequent in the IGD group than in the clinical comparison group. Conclusion: The GADIS-A had good to excellent psychometric properties in Turkish adolescents. Despite having a stricter diagnostic criterion, GD overlapped with IGD in a clinical population