Influence of COX-2 and OXTR polymorphisms on treatment outcome in treatment resistant depression.

Inflammatory pathways play a crucial role in the pathomechanisms of antidepressant efficacy. The aim of this study was to investigate whether a set of single nucleotide polymorphisms (SNPs) within cyclooxygenase-2 (COX-2, rs5275 and rs20417) and oxytocin receptor (OXTR, rs53576 and rs2254298) genes was associated with antidepressant treatment resistance, response or remission. Three hundred seventy-two patients were recruited in the context of a multicenter resistant depression study. They were genotyped for COX-2 and OXTR SNPs. Treatment resistance (according to two different definitions), response and remission were recorded. We did not observe any association between the genotypes or alleles of the selected SNPs within COX-2 and OXTR genes and treatment resistance, response and remission in the whole sample. Our results are consistent with those of some studies but not with those of other ones. Indeed, several factors could be involved in the discrepancy observed across studies. They include sample size, environmental factors, differences in ethnicity, different study designs, and different definitions of treatment resistance.

Failure to replicate influence of GRIK4 and GNB3 polymorphisms on treatment outcome in major depression.

In the present study, we aimed to confirm the previous finding of an association between GRIK4 and GNB3 variants (rs195478 and rs5443) and remission and treatment resistance in major depression, using a multicenter sample of 223 patients. We did not find any supporting evidence for such associations. These conflicting data may result from difficulties in the replication of candidate gene association studies.

Switching antidepressant class does not improve response or remission in treatment-resistant depression.

OBJECTIVE: The management of treatment-resistant depression is a much debated issue. In particular, the evidence supporting the commonly suggested sequential use of antidepressants from 2 different pharmacological classes is weak. This retrospective study was undertaken to investigate whether there is a better response in nonresponders switched to a different class of antidepressants (across-class) compared with nonresponders switched to an antidepressant from the same class (within-class). METHODS: Three hundred forty patients with primary major depressive disorder were recruited in the context of a European multicenter project. Subjects whose current depressive episode had failed to respond to a first antidepressant trial of adequate dose and duration were included. RESULTS: There was no significant difference in response or remission rates between the across-class and within-class groups after controlling for possible confounders. CONCLUSIONS: In depressed nonresponders to a previous antidepressant treatment, switching to a different class of antidepressants was not associated with a better response or remission rate.

COMT and age at onset in mood disorders: a replication and extension study.

Our study aims at replicating our previous finding of an association between COMT rs4680 G/A polymorphism and early onset major depression (MD). We included 462 MD, 147 bipolar disorders (BD) subjects and 295 healthy controls. We could partially replicate previous findings. In particular, rs4680 GG+AG genotypes were more represented in the subgroup of early onset MD patients (p=0.04). Additionally, we observed an association between rs737865 alleles and early onset MD (p=0.04). Rs4680 genotype was associated with early onset BD as well (p=0.01). In conclusion, we partially replicated our previous findings confirming a possible influence of COMT variants in MD and BD, particularly in early onset subjects, though not with the same risk genotypes.

No influence of PTGS2 polymorphisms on response and remission to antidepressants in major depression.

In the present study, aimed at investigating whether a set of single nucleotide polymorphisms (SNPs) within PTGS2 gene (rs4648276, rs2066826 and rs689466) could be associated with antidepressant response, remission and treatment resistance in a sample of major depression patients, we did not find evidence supporting any of such associations.

A preliminary investigation of the influence of CREB1 gene on treatment resistance in major depression.

BACKGROUND: The transcription factor Cyclic adenosine monophosphate Response Element Binding (CREB) protein has been repeatedly involved in the aetiology and pharmacotherapy of major depression (MD). The aim of this study was to investigate the potential association of a set of single nucleotide polymorphisms (SNPs) in CREB1 gene and both MD and response, remission and treatment resistance to antidepressants. METHODS: One hundred-ninety MD patients collected in the context of a resistant depression study and treated with antidepressants for at least 4weeks were genotyped for 5 CREB1 SNPs (rs2709376, rs2253206, rs7569963, rs7594560, and rs4675690). Response, remission and treatment resistance were recorded. RESULTS: An allele of rs7569963 as well as rs2253206-rs7569963 A-A and rs7569963-rs4675690 A-C haplotypes were associated with the status of treatment resistance. Additionally, rs7569963 GG genotype was positively associated with remission. No further significant associations were observed. LIMITATIONS: Limitations of the present study include a relatively small sample size and the incomplete ascertainment of data which could influence the outcome. CONCLUSIONS: Our results preliminary suggest that some genetic polymorphisms in CREB1 could be associated to treatment resistance. Although such finding needs to be replicated in larger samples, it increases current knowledge about the genetic predictors of response to antidepressants that will probably lead to enhance treatment outcomes by addressing each individual to the most appropriate treatment strategy in the early stages of treatment.

Cytochrome P450 CYP1A2, CYP2C9, CYP2C19 and CYP2D6 genes are not associated with response and remission in a sample of depressive patients.

Cytochrome P450 genes are involved in the metabolism of antidepressants and could influence treatment response. The aim of this study was to investigate the role of allelic variations of the cytochrome P450 CYP1A2, CYP2C9, CYP2C19 and CYP2D6 genes in antidepressant treatment response and remission rates. Two hundred and seventy-eight patients affected by major depression, responders (N = 81) and nonresponders (N=197) to at least one adequate antidepressant treatment, were recruited with a multicentre design for resistant depression and genotyped for all relevant variations. None of the considered metabolic profiles (e.g. poor, intermediate, extensive and ultrarapid metabolizers) was found to be associated with either response or remission rates. In conclusion, the investigated cytochrome genes do not seem to play a major role in antidepressant response in the present sample of depressive patients. Nevertheless, methodological and sample size limitations of this study do not allow definitive conclusions.

Clinical factors associated with treatment resistance in major depressive disorder: results from a European multicenter study.

OBJECTIVES: Very few studies have investigated clinical features associated with treatment-resistant depression (TRD) defined as failure of at least 2 consecutive antidepressant trials. The primary objective of this multicenter study was to identify specific clinical and demographic factors associated with TRD in a large sample of patients with major depressive episodes that failed to reach response or remission after at least 2 consecutive adequate antidepressant treatments. METHOD: A total of 702 patients with DSM-IV major depressive disorder, recruited from January 2000 to February 2004, were included in the analysis. Among them, 346 patients were considered as nonresistant. The remaining 356 patients were considered as resistant, with a 17-item Hamilton Rating Scale for Depression score remaining greater than or equal to 17 after 2 consecutive adequate antidepressant trials. Cox regression models were used to examine the association between individual clinical variables and TRD. RESULTS: Among the clinical features investigated, 11 variables were found to be associated with TRD. We found anxiety comorbidity (p < .001, odds ratio [OR] = 2.6), comorbid panic disorder (p < .001, OR = 3.2) and social phobia (p = .008, OR = 2.1), personality disorder (p = .049, OR = 1.7), suicidal risk (p = .001, OR = 2.2), severity (p = .001, OR = 1.7), melancholia (p = .018, OR = 1.5), a number of hospitalizations > 1 (p = .003, OR = 1.6), recurrent episodes (p = .009, OR = 1.5), early age at onset (p = .009, OR = 2.0), and nonresponse to the first antidepressant received lifetime (p = .019, OR = 1.6) to be the factors associated with TRD. CONCLUSIONS: Our findings provide a set of 11 relevant clinical variables associated with treatment resistance in major depressive disorder that can be explored at the clinical level. The statistical model used in this analysis allowed for a hierarchy of these variables (based on the OR) showing that comorbid anxiety disorder is the most powerful clinical factor associated with TRD.