Gene Expression Studies in Major Depression

The dramatic technical advances in methods to measure gene expression on a genome-wide level thus far have not been paralleled by breakthrough discoveries in psychiatric disorders—including major depression (MD)—using these hypothesis-free approaches. In this review, we first describe the methodologic advances made in gene expression analysis, from quantitative polymerase chain reaction to next-generation sequencing. We then discuss issues in gene expression experiments specific to MD, ranging from the choice of target tissues to the characterization of the case group. We provide a synopsis of the gene expression studies published thus far for MD, with a focus on studies using mRNA microarray methods. Finally, we discuss possible new strategies for the gene expression studies in MD that circumvent some of the addressed issues

Transition to Mania During Treatment of Bipolar Depression

Some individuals with bipolar disorder transition directly from major depressive episodes to manic, hypomanic, or mixed states during treatment, even in the absence of antidepressant treatment. Prevalence and risk factors associated with such transitions in clinical populations are not well established, and were examined in the Systematic Treatment Enhancement Program for Bipolar Disorder study, a longitudinal cohort study. Survival analysis was used to examine time to transition to mania, hypomania, or mixed state among 2166 bipolar I and II individuals in a major depressive episode. Cox regression was used to examine baseline clinical and sociodemographic features associated with hazard for such a direct transition. These features were also examined for interactive effects with antidepressant treatment. In total, 461/2166 subjects in a major depressive episode (21.3%) transitioned to a manic/hypomanic or mixed state before remission, including 289/1475 (19.6%) of those treated with antidepressants during the episode. Among the clinical features associated with greatest transition hazard were greater number of past depressive episodes, recent or lifetime rapid cycling, alcohol use disorder, previous suicide attempt, and history of switch while treated with antidepressants. Greater manic symptom severity was also associated with risk for manic transition among both antidepressant-treated and antidepressant-untreated individuals. Three features, history of suicide attempt, younger onset age, and bipolar subtype, exhibited differential effects between individuals treated with antidepressants and those who were not. These results indicate that certain clinical features may be associated with greater risk of transition from depression to manic or mixed states, but the majority of them are not specific to antidepressant-treated patients

Interaction of FKBP5, a Stress-Related Gene, with Childhood Trauma Increases the Risk for Attempting Suicide

Childhood trauma is associated with hypothalamic–pituitary–adrenal (HPA) axis dysregulation and is a known risk factor for suicidal behavior. In this study we sought to determine whether the impact of childhood trauma on suicide risk might be modified by FKBP5, an HPA-axis regulating gene. Sixteen FKBP5 haplotype-tagging single nucleotide polymorphisms (SNPs) were genotyped in a sample of African Americans: 398 treatment-seeking patients with substance dependence (90% men; 120 suicide attempters) and 432 nonsubstance-dependent individuals (40% men; 21 suicide attempters). In all, 474 participants (112 suicide attempters) also completed the Childhood Trauma Questionnaire (CTQ). Primary haplotype analyses were conducted with the four SNPs implicated in earlier studies: rs3800373, rs9296158, rs1360780, and rs9470080. We found that childhood trauma was associated with suicide attempt (P<0.0001). Although there was no main effect of the two major yin yang haplotypes in the four SNP haplotype blocks, there was a haplotype influence on suicide risk (p=0.006) only in individuals exposed to high levels of childhood trauma. In this group, 51% with two copies of the risk haplotype, 36% with one copy, and 20% with no copies had attempted suicide. The total logistic regression model accounted for 13% of the variance in attempted suicide. Analyses of the 16 SNPs showed significant main effects on suicide attempt of rs3777747, rs4713902, and rs9470080 and interactive effects of rs3800373, rs9296158, and rs1360780 with CTQ score on suicide attempt. These data suggest that childhood trauma and variants of the FKBP5 gene may interact to increase the risk for attempting suicide