A cluster model of temperament as an indicator of antidepressant response and symptom severity in major depression

Genetic risk scores associated with temperament clusters in Finnish depression patients

OBJECTIVE

Cloninger's temperament dimensions have been studied widely in relation to genetics. In this study, we examined Cloninger's temperament dimensions grouped with cluster analyses and their association with single nucleotide polymorphisms (SNPs). This study included 212 genotyped Finnish patients from the Ostrobothnia Depression Study.

METHODS

The temperament clusters were analysed at baseline and at six weeks from the beginning of the depression intervention study. We selected depression-related catecholamine and serotonin genes based on a literature search, and 59 SNPs from ten different genes were analysed. The associations of single SNPs with temperament clusters were studied. Using the selected genes, genetic risk score (GRS) analyses were conducted considering appropriate confounding factors.

RESULTS

No single SNP had a significant association with the temperament clusters. Associations between GRSs and temperament clusters were observed in multivariate models that were significant after permutation analyses. Two SNPs from the DRD3 gene, two SNPs from the SLC6A2 gene, one SNP from the SLC6A4 gene, and one SNP from the HTR2A gene associated with the HHA/LRD/LP (high harm avoidance, low reward dependence, low persistence) cluster at baseline. Two SNPs from the HTR2A gene were associated with the HHA/LRD/LP cluster at six weeks. Two SNPs from the HTR2A gene and two SNPs from the COMT gene were associated with the HP (high persistence) cluster at six weeks.

CONCLUSION

GRSs seem to associate with an individual's temperament profile, which can be observed in the clusters used. Further research needs to be conducted on these types of clusters and their clinical applicability.

The efficacy of levomilnacipran ER across symptoms of major depressive disorder: a post hoc analysis of 5 randomized, double-blind, placebo-controlled trials

OBJECTIVE

A post hoc analysis evaluated the effects of levomilnacipran ER on individual symptoms and symptom domains in adults with major depressive disorder (MDD).

METHODS

Data were pooled from 5 Phase III trials comprising 2598 patients. Effects on depression symptoms were analyzed based on change from baseline in individual Montgomery-Åsberg Depression Rating Scale (MADRS) item scores. A1dditional evaluations included resolution of individual symptoms (defined as a MADRS item score ≤1 at end of treatment) and concurrent resolution of all 10 MADRS items, all MADRS6 subscale items, and all items included in different symptom clusters (Dysphoria, Retardation, Vegetative Symptoms, Anhedonia).

RESULTS

Significantly greater mean improvements were found on all MADRS items except Reduced Appetite with levomilnacipran ER treatment compared with placebo. Resolution of individual symptoms occurred more frequently with levomilnacipran ER than placebo for each MADRS item (all P<.05), with odds ratios (ORs) ranging from 1.26 to 1.75; resolution of all 10 items was also greater with levomilnacipran ER (OR=1.57; P=.0051). Significant results were found for the MADRS6 subscale (OR=1.73; P<.0001) and each symptom cluster (OR range, 1.39 [Vegetative Symptoms] to 1.84 [Retardation]; all clusters, P<.01).

CONCLUSION

Adult MDD patients treated with levomilnacipran ER improved across a range of depression symptoms and symptom domains.

Prediction of long-term treatment response to selective serotonin reuptake inhibitors (SSRIs) using scalp and source loudness dependence of auditory evoked potentials (LDAEP) analysis in patients with major depressive disorder

BACKGROUND

Animal and clinical studies have demonstrated that the loudness dependence of auditory evoked potentials (LDAEP) is inversely related to central serotonergic activity, with a high LDAEP reflecting weak serotonergic neurotransmission and vice versa, though the findings in humans have been less consistent. In addition, a high pretreatment LDAEP appears to predict a favorable response to antidepressant treatments that augment the actions of serotonin. The aim of this study was to test whether the baseline LDAEP is correlated with response to long-term maintenance treatment in patients with major depressive disorder (MDD).

METHODS

Scalp N1, P2 and N1/P2 LDAEP and standardized low resolution brain electromagnetic tomography-localized N1, P2, and N1/P2 LDAEP were evaluated in 41 MDD patients before and after they received antidepressant treatment (escitalopram (n = 32, 10.0 ± 4.0 mg/day), sertraline (n = 7, 78.6 ± 26.7 mg/day), and paroxetine controlled-release formulation (n = 2, 18.8 ± 8.8 mg/day)) for more than 12 weeks. A treatment response was defined as a reduction in the Beck Depression Inventory (BDI) score of >50% between baseline and follow-up.

RESULTS

The responders had higher baseline scalp P2 and N1/P2 LDAEP than nonresponders (p = 0.017; p = 0.036). In addition, changes in total BDI score between baseline and follow-up were larger in subjects with a high baseline N1/P2 LDAEP than those with a low baseline N1/P2 LDAEP (p = 0.009). There were significantly more responders in the high-LDAEP group than in the low-LDAEP group (p = 0.041).

CONCLUSIONS

The findings of this study reveal that a high baseline LDAEP is associated with a clinical response to long-term antidepressant treatment.