The COMT rs4680 polymorphism and suicide attempt in rural Shandong, China

Suicidal ideation and aggression in childhood, genetic variation and young adult depression

BACKGROUND

Suicidal thoughts and behaviors have been studied in association with a variety of risk factors. The aim of the present study was to determine if levels of child/adolescent aggression and/or variation in candidate genes previously associated with suicidal behaviors in adults would influence the presence of suicidal ideation in childhood/adolescence, and to determine if ideation was associated with young adult depression.

METHODS

A longitudinal study of children, adolescents and young adults who were at high or low risk for alcohol and other substance use disorders by familial background were assessed. The Child Behavior Checklist (CBCL) aggression scale scores with derived subtypes (physical and relational) and genetic variation (ANKK1, DRD2, COMT, SLC6A4, HTR2C) were used as predictors of the presence and onset of suicidal ideation in childhood using survival analysis. Structural equation models (SEM) were fit to determine the relative importance of the predictors controlling for background variables.

RESULTS

CBCL aggression was significantly associated with child/adolescent suicidal ideation. One SNP in the ANKK1 gene (rs1800497), one in the HTR2C gene (rs6318), and two haplotypes, AAAC in the ANKK1-DRD2 complex and the CCC haplotype of the HTR2C gene, were significantly associated with the presence and onset of child/adolescent suicidal ideation. Follow up in young adulthood showed a significant relationship between suicidal ideation in childhood/adolescence and young adult depression.

CONCLUSIONS

Genetic variation and presence of elevated aggression scores from the childhood CBCL are significant predictors of childhood suicidal ideation. Suicidal ideation in childhood and being female are predictors of young adult depression.

Stressful life events, insomnia and suicidality in a large sample of Chinese adolescents

AIMS

This study aimed to examine the associations between stressful life events, insomnia, and suicidality including suicidal ideation (SI), suicide plan (SP) and suicide attempt (SA) in a large sample of Chinese adolescents.

METHODS

A total of 11,831 adolescents who participated in the baseline survey of Shandong Adolescent Behavior and Health Cohort were included for the analysis. Participants were sampled from 8 middle/high schools in 3 counties of Shandong, China. Participants completed a structured behavior and health questionnaire, including suicidality, demographics, depression/anxiety, stressful life events (SLEs), and insomnia in November-December 2015. A series of logistic regression models and mediation analyses were performed to examine the associations between SLEs, insomnia and suicidality.

RESULTS

The prevalence rates of overall suicidality, SI, SP and SA in the last year were 13.1%, 12.5%, 3.3%, and 1.5%, respectively. SLEs were significantly associated with overall suicidality, SI, and SP. Insomnia was an independent risk factor of suicidality and a mediator of the association between SLEs and suicidality. The total effect of SLEs on overall suicidality was 0.597 (95%CI: 0.534-0.661), including 0.457 (95%CI: 0.391-0.523) for direct effect and 0.158 (95%CI: 0.138-0.178) for indirect effect. Insomnia also mediated the associations of SLEs with SI, SP and SA, respectively.

LIMITATIONS

Causal relationship could not be concluded because this study is cross-sectional.

CONCLUSIONS

Stressful life events and insomnia are directly associated with suicidality in adolescents. The association between SLEs and suicidality is partially mediated by insomnia.

Association between Polymorphisms of the DRD2 and ANKK1 Genes and Suicide Attempt: A Preliminary Case-Control Study in a Mexican Population

BACKGROUND

The aim of this study was to analyze the possible association of polymorphic variants of the DRD2 and ANKK1 genes with suicide attempt in a Mexican population.

METHODS

We conducted a case-control study in 289 subjects (166 suicide attempters and 123 healthy controls). We genotyped 2 polymorphisms of DRD2 (rs6275 and rs1799978) and 1 polymorphism of ANKK1 (rs1800497); then we analyzed the association between suicide attempt and these polymorphisms through genotypes, alleles, and inheritance models.

RESULTS

Individuals who carried the TT genotype of the rs1800497 showed a 3-fold risk of attempting suicide (OR = 3.01; 95% CI 1.56-5.81, p = 0.001) when evaluated through the recessive model. In an analysis stratified by gender, this risk factor remained present among females (OR = 2.81; 95% CI 1.37-5.75) as well as males (OR = 3.3; 95% CI 1.01-10.77).

CONCLUSION

Our results suggest that the rs1800497 variant of the ANKK1 gene could increase the risk of suicide attempt in a Mexican population. However, further studies using larger samples are necessary to obtain more conclusive results.

The role of COMT gene Val108/158Met polymorphism in suicidal behavior: systematic review and updated meta-analysis

BACKGROUND

It is accepted that there is a genetic factor that influences the risk of suicidal behavior. The catechol-O-methyltransferase (COMT) gene, especially the Val108/158Met polymorphism, has been associated with suicide; however, no conclusive outcome has been attained. Therefore, the aim of the present study was to assess the role of COMT Val108/158Met in suicidal behavior throughout an updated meta-analysis.

METHODS

We performed an online search using PubMed and Web of Science (up to March 2017). Our systematic review included case-control studies of individuals who attempted suicide and completed suicide. We tested allelic, homozygous, heterozygous, dominant, and recessive inheritance models. The meta-analysis was performed in accordance with the statement of Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

The meta-analysis comprised 17 studies, which included 3,282 cases and 3,774 controls, and showed that when evaluating the overall population, the Val108/158Met polymorphism of COMT was not associated with suicidal behavior in any of the inheritance models; however, the subanalyses showed that this polymorphism exhibits a risk factor in males and a protective effect in females. Additionally, it conveyed a risk factor in Asian populations when using the allelic (OR 1.25; CI: 1.04-1.51) and recessive models (OR 1.32; CI: 1.03-1.68).

CONCLUSION

Our updated meta-analysis suggests a possible association between COMT Val108/158Met and suicidal behavior in Asian populations. However, in view of the small number of studies, these results should be considered exploratory. We recommend that more studies be performed with larger samples.

Characteristics of suicide completers and attempters in rural Chinese population

OBJECTIVE

This study aimed to compare the similarities and differences between suicide completers and attempters in rural China.

METHODS

Two paired case-control studies of completed suicide and suicide attempts were conducted in rural Shandong, China. This analysis included 409 suicide attempters (SA) with a mean age of 43.90 (SD=13.31), 117 suicide completers (SC) with a mean age of 50.38 (SD=13.02) and their controls matched by gender, age (within 3years), and residence. Logistic regression models were used to examine risk factors of suicide attempts and completed suicide and the differences between SA and SC.

RESULTS

Compared to their matched controls, suicide attempters and completers shared the following common risk factors: low levels of education (middle school or under) (OR, 95% CI: 2.79, 1.40-5.55 for SA and 16.98, 1.59-181.60 for SC), negative life events (OR, 95% CI: 7.37, 4.73-11.50 for SA and 21.08, 4.74-93.71 for SC), and mental disorders (OR, 95% CI: 7.52, 3.85-14.69 for SA and 22.39, 2.65-189.60 for SC). Compared to suicide attempts, completed suicide was associated with the following risk factors: male gender (OR, 95% CI: 1.75, 1.06-2.90), advancing age (OR, 95% CI: 1.02, 1.00-1.04), poor family economic status (OR, 95% CI: 6.74, 3.22-14.13), prior suicide attempts (OR, 95% CI: 2.43, 1.18-4.97), family suicide history (OR, 95% CI: 2.59, 1.33-5.06), high suicide intent (OR, 95% CI: 1.15, 1.05-1.27), and highly lethal methods (OR, 95% CI: 13.65, 6.51-28.59).

CONCLUSIONS

Although suicide completers and attempters share some common risk factors, suicide completers are more likely to have prior suicide attempts, family suicide history, and higher suicidal intent, and to use highly lethal methods in rural Chinese.