J. Hennings

Polymorphisms in GRIK4, HTR2A, and FKBP5 show interactive effects in predicting remission to antidepressant treatment.

Single-nucleotide polymorphisms (SNPs) in the FKBP5, GRIK4, and HTR2A genes have been shown to be associated with response to citalopram treatment in the STAR*D sample, but only associations with FKBP5 have so far been tested in the Munich Antidepressant Response Signature (MARS) project. Response and remission of depressive symptoms after 5 weeks of antidepressant treatment were tested against 82 GRIK4 and 37 HTR2A SNPs. Association analysis was conducted in about 300 depressed patients from the MARS project, 10% of whom had bipolar disorder. The most predictive SNPs from these two genes and rs1360780 in FKBP5 were then genotyped in a total of 387 German depressed in-patients to analyze potential additive and interactive effects of these variants. We could not replicate previous findings of the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study in our sample. Although not statistically significant, the effect for the best GRIK4 SNP of STAR*D (rs1954787, p=0.076, pcorrected=0.98) seemed to be in the same direction. On the other hand, the nominally significant association with the top HTR2A SNPs of STAR*D (rs7997012, allelic, p=0.043, pcorrected=0.62) was with the opposite risk allele. The GRIK4 SNP (rs12800734, genotypic, p=0.0019, pcorrected=0.12) and the HTR2A SNP (rs17288723, genotypic, p=0.0011, pcorrected=0.02), which showed the strongest association with remission in our sample, had not been reported previously. Associations across all genetic markers within the GRIK4 (genotypic, p=0.022) or HTR2A (genotypic, p=0.012) locus using the Fishers product method (FPM) were also significant. In all 374 patients, the best predictive model included a main effect for GRIK4 rs12800734 and two significant interactions between GRIK4 rs12800734 and FKBP5 rs1360780, and GRIK4 rs12800734 and HTR2A rs17288723. This three SNP model explained 13.1% of the variance for remission after 5 weeks (p=0.00051 for the model). Analyzing a sub-sample of 194 patients, plasma ACTH (p=0.002) and cortisol (p=0.021) responses of rs12800734 GG (GRIK4) carriers, who also showed favorable treatment response, were significantly lower in the second combined dexamethasone (dex)/corticotrophin-releasing hormone (CRH) test before discharge compared with the other two genotype groups. Despite large differences in ethnicity and design compared with the STAR*D study, our results from the MARS study further support both independent and interactive involvement of GRIK4, HTR2A and FKBP5 in antidepressant treatment response.

Clinical characteristics and treatment outcome in a representative sample of depressed inpatients – Findings from the Munich Antidepressant Response Signature (MARS) project

Depression is a common and often difficult-to-treat clinical condition with a high rate of patients showing insufficient treatment response and persistence of symptoms. We report the characteristics of a representative sample of depressed inpatients participating in the Munich Antidepressant Response Signature (MARS) project. Eight hundred and forty-two inpatients admitted to a psychiatric hospital for treatment of a major depressive episode, recurrent or bipolar depression were thoroughly characterized with respect to demographic factors, clinical history, and the degree of HPA-axis dysregulation evaluated by means of combined dex/CRH tests, and the predictive value of these factors for treatment outcome is investigated. 80.8% of patients responded to treatment (i.e., improvement in symptom severity of at least 50%) and 57.9% reached remission (i.e., near absence of residual depressive symptoms) at discharge after a mean treatment period of 11.8 weeks. Regression analysis identified early partial response (within 2 weeks) as the most important positive predictor for achieving remission. Previous ineffective treatment trials in the current episode and presence of a migration background are potent negative predictors for treatment outcome. In addition, remitters were characterized by a more pronounced normalization of an initially dysregulated HPA-axis. We could show that a large majority of inpatients suffering from depression benefits from antidepressant treatment during hospitalization. However, a considerable number of patients failed to achieve remission. We demonstrated that this subgroup can be characterized by a set of demographic, clinical and neuroendocrine variables allowing to predict unfavorable outcome at an early stage of treatment.

Association of genetic variants in the neurotrophic receptor-encoding gene NTRK2 and a lifetime history of suicide attempts in depressed patients.

CONTEXT A consistent body of evidence supports a role of reduced neurotrophic signaling in the pathophysiology of major depressive disorder (MDD) and suicidal behavior. Especially in suicide victims, lower postmortem brain messenger RNA and protein levels of neurotrophins and their receptors have been reported. OBJECTIVE To determine whether the brain-derived neurotrophic factor (BDNF) gene or its high-affinity receptor gene, receptor tyrosine kinase 2 (NTRK2), confer risk for suicide attempt (SA) and MDD by investigating common genetic variants in these loci. DESIGN Eighty-three tagging single-nucleotide polymorphisms (SNPs) covering the genetic variability of these loci in European populations were assessed in a case-control association design. SETTING Inpatients and screened control subjects. PARTICIPANTS The discovery sample consisted of 394 depressed patients, of whom 113 had SA, and 366 matched healthy control subjects. The replication studies comprised 744 German patients with MDD and 921 African American nonpsychiatric clinic patients, of whom 152 and 119 were positive for SA, respectively. INTERVENTIONS Blood or saliva samples were collected from each participant for DNA extraction and genotyping. MAIN OUTCOME MEASURES Associations of SNPs in BDNF and NTRK2 with SA and MDD. RESULTS Independent SNPs within NTRK2 were associated with SA among depressed patients of the discovery sample that could be confirmed in both the German and African American replication samples. Multilocus interaction analysis revealed that single SNP associations within this locus contribute to the risk of SA in a multiplicative and interactive fashion (P = 4.7 x 10(-7) for a 3-SNP model in the combined German sample). The effect size was 4.5 (95% confidence interval, 2.1-9.8) when patients carrying risk genotypes in all 3 markers were compared with those without any of the 3 risk genotypes. CONCLUSIONS Our results suggest that a combination of several independent risk alleles within the NTRK2 locus is associated with SA in depressed patients, further supporting a role of neurotrophins in the pathophysiology of suicide.

Genome-Wide Association Study of Antidepressant Treatment-Emergent Suicidal Ideation

Emergence of suicidal ideation (TESI) during treatment with antidepressants in major depression led to a black box warning. We performed a genome-wide association study to identify genetic markers, which increase the risk for this serious side effect. TESI was evaluated in depressed in-patients (N=397) and defined by an emergence of suicidal thoughts during hospitalization without suicidal thoughts at admission using the suicide item (3) of the Hamilton Depression Rating Scale. Genotype distribution of 405.383 single-nucleotide polymorphisms (SNPs) in patients with TESI (N=32/8.1%) was compared to patients without increase in suicidal ideation (N=329/82.9%) and to a subgroup never reported suicidal ideation (N=79/19.9%). Top results were analyzed in an independent sample (N=501). None variant reached genome-wide significance, the best associated SNP was rs1630535 (p-value=1.3 × 10−7). The top 79 SNPs could be analyzed in an independent sample, and 14 variants showed nominal significant association with the same risk allele in the replication sample. A discriminant analysis classifying patients using these 79 SNPs revealed a 91% probability to classify TESI vs non-TESI cases correctly in the replication sample. Although our data need to be interpreted carefully owing to the small numbers in both cohorts, they suggest that a combination of genetic markers might indeed be used to identify patients at risk for TESI.

Successful treatment of tardive lingual dystonia with botulinum toxin: case report and review of the literature.

Tardive dyskinesia (TD) is a dreaded side effect of antipsychotic medication. Recommended treatments for TD may provide reliable improvement but can be, in turn, associated with additional adverse reactions. Recently, several reports have suggested that botulinum toxin A (BTX-A) injection in affected muscles may significantly improve TD. Here, we report a case of severe tongue protrusion dystonia secondary to an antipsychotic medication in a young man. Several approaches including clozapine, amisulpride, aripiprazole, ziprasidone, tiapride and clonazepam failed to improve the symptoms. Injection of 50 U of BTX-A (Dysport, Ipsen, Ettlingen, Germany) into each genioglossal muscle dramatically improved tongue protrusion within few days with a sustained effect. If reasonable precautions are taken, the application seems to be well tolerated with only minor side effects. A review of the literature that is part of this article adverts BTX-A injection as a potential beneficial approach of various kinds of TD.

Suppressive effect of mirtazapine on the HPA system in acutely depressed women seems to be transient and not related to antidepressant action

Impaired regulation of the hypothalamus-pituitary-adrenocortical (HPA) system is a consistent finding among patients with depression, which can be most sensitively detected with the combined dexamethasone (dex)/corticotrophin releasing hormone (CRH) test. The majority of patients with acute depression shows an exaggerated plasma corticotrophin (ACTH) and cortisol response to this test that normalizes gradually during successful antidepressant therapy. In contrast, persistently high HPA-responses to this challenge are prognostically less favorable. It has been recently questioned, whether this observation applies also to treatment with the atypical antidepressant mirtazapine, as patients treated with this drug showed a distinct attenuation of the endocrine response to the dex/CRH test already after 1 week of treatment. In the present study, we investigated whether the attenuating effect of mirtazapine on the HPA system is an acute pharmacological reaction disappearing after physiological adaptation or whether this effect is related to the antidepressant action of the drug. We examined plasma ACTH and cortisol responses to the dex/CRH test in acutely depressed inpatients treated either with mirtazapine (n=55) or a monoamine reuptake inhibitor (n=105) according to doctors choice and compared the test results with healthy controls (n=40). Patients treated with monoamine reuptake inhibitors received either selective serotonin reuptake inhibitors (SSRI), tricyclic antidepressants (TCA) or the combined serotonin and noradrenalin reuptake inhibitor venlafaxine. We found increased plasma ACTH and cortisol responses to the dex/CRH test in depressed patients compared with healthy controls, but also significantly (p=.017) attenuated plasma cortisol secretion in the mirtazapine group compared to the group of monoamine reuptake inhibitor treated patients. This effect was not significant in male patients. Furthermore this effect was independent of the psychopathological state, but depended on treatment duration. Patient treatment with mirtazapine for up to 7 days resulted in dex/CRH test outcome that was indistinguishable from controls. This effect, however waned as it was not observable in patients treated for a longer period. These results suggest that short-term administration of mirtazapine has immediate but only transient suppressive effects on the HPA system predominantly in women. Our results confirm that dex/CRH tests can be used as predictors of clinical course also under mirtazapine treatment.

Glucose Metabolism and Antidepressant Medication

Impaired glucose tolerance is observed in depressed patients, and patients suffering from depression have an increased risk to develop diabetes mellitus. In depressed and diabetic patients, studies have shown both a beneficial effect of antidepressants on glucose homeostasis and the opposite. This review aims to structure the conflicting data and focuses on the question, which effect specific antidepressants have on glucose homeostasis. We therefore performed a systematic review of all available studies referenced in Medline from 1960 to 2011. We included antidepressant agents indexed in the Anatomical Therapeutic Chemical (ATC) classification system of the WHO in 2011 and searched for studies investigating their effects on glucose metabolism in clinical samples as well as in healthy subjects. Of 876 studies screened we included 66. Most studies had small sample sizes and lacked a placebo group limiting conclusions about antidepressant effects on glucose tolerance. However, some evidence points to beneficial effects on glucose homeostasis of hydrazine-type monoamine oxidase inhibitors (MAOIs) and selective serotonin reuptake inhibitors (SSRIs). In case of SSRIs, the effect is more pronounced in diabetic patients or patients with comorbid depression and diabetes mellitus. Noradrenegic substances (and possibly also dualacting antidepressants), in contrast, may deteriorate glucose tolerance. They can be used in depressed patients when favorable effects on mood outweigh adverse metabolic effects, but in depressed diabetics this can be at the expense of worsening of glycemic control. The effects of other antidepressants, like bupropione, mirtazapine or newer agents, require further investigation before reliable conclusions can be made. The synthesis of the findings is discussed in light of the specific pharmacodynamic properties of the antidepressants as well as the pathophysiological changes in depression and impaired glucose homeostasis, including animal studies.

Mirtazapine provokes periodic leg movements during sleep in young healthy men.

STUDY OBJECTIVES Recent evidence suggests that certain antidepressants are associated with an increase of periodic leg movements (PLMS) that may disturb sleep. So far, this has been shown in patients clinically treated for depression and in cross-sectional studies for various substances, but not mirtazapine. It is unclear whether antidepressants induce the new onset of PLMS or only increase preexisting PLMS, and whether this is a general property of the antidepressant or only seen in depressed patients. We report here the effect of mirtazapine on PLMS in young healthy men. DESIGN Open-labeled clinical trial (NCT00878540) including a 3-week preparatory phase with standardized food, physical activity, and sleep-wake behavior, and a 10-day experimental inpatient phase with an adaptation day, 2 baseline days, and 7 days with mirtazapine. SETTING Research institute. PARTICIPANTS Twelve healthy young (20-25 years) men. INTERVENTIONS Seven days of nightly intake (22:00) of 30 mg mirtazapine. MEASUREMENTS AND RESULTS Sleep was recorded on 2 drug-free baseline nights, the first 2 drug nights, and the last 2 drug nights. Eight of the 12 subjects showed increased PLMS after the first dose of mirtazapine. Frequency of PLMS was highest on the first drug night and attenuated over the course of the next 6 days. Three subjects reported transient restless legs symptoms. CONCLUSIONS Mirtazapine provoked PLMS in 67% of young healthy males. The effect was most pronounced in the first days. The possible role of serotonergic, noradrenergic and histaminergic mechanisms in mirtazapine-induced PLMS is discussed.

Resistance to antidepressant treatment is associated with polymorphisms in the leptin gene, decreased leptin mRNA expression, and decreased leptin serum levels.

Leptin, a peptide hormone from adipose tissue and key player in weight regulation, has been suggested to be involved in sleep and cognition and to exert antidepressant-like effects, presumably via its action on the HPA-axis and hippocampal function. This led us to investigate whether genetic variants in the leptin gene, the level of leptin mRNA-expression and leptin serum concentrations are associated with response to antidepressant treatment. Our sample consisted of inpatients from the Munich Antidepressant Response Signature (MARS) project with weekly Hamilton Depression ratings, divided into two subsamples. In the exploratory sample (n=251) 17 single nucleotide polymorphisms (SNPs) covering the leptin gene region were genotyped. We found significant associations of several SNPs with impaired antidepressant treatment outcome and impaired cognitive performance after correction for multiple testing. The SNP (rs10487506) showing the highest association with treatment response (p=3.9×10(-5)) was analyzed in the replication sample (n=358) and the association could be verified (p=0.021) with response to tricyclic antidepressants. In an additional meta-analysis combining results from the MARS study with data from the Genome-based Therapeutic Drugs for Depression (GENDEP) and the Sequenced Treatment Alternatives to Relieve Depression (STAR(⁎)D) studies, nominal associations of several polymorphisms in the upstream vicinity of rs10487506 with treatment outcome were detected (p=0.001). In addition, we determined leptin mRNA expression in lymphocytes and leptin serum levels in subsamples of the MARS study. Unfavorable treatment outcome was accompanied with decreased leptin mRNA and leptin serum levels. Our results suggest an involvement of leptin in antidepressant action and cognitive function in depression with genetic polymorphisms in the leptin gene, decreased leptin gene expression and leptin deficiency in serum being risk factors for resistance to antidepressant therapy in depressed patients.

Glucose tolerance in depressed inpatients, under treatment with mirtazapine and in healthy controls.

Impaired glucose tolerance and diabetes have been associated with depression, and antidepressant treatment is assumed to improve impaired glucose tolerance. However, antidepressant treatment is also considered as a risk factor for the development of diabetes. Reports about glucose tolerance under antidepressant treatment frequently lack appropriate control groups. We conducted the oral glucose tolerance test (OGTT) in 10 healthy controls selected from an epidemiological sample with a negative lifetime history of mental Axis I disorder. Controls were carefully matched to a sample of inpatients with major depression that participated in an OGTT before and after antidepressant treatment with mirtazapine. All participants underwent a standard OGTT protocol. In patients, a second (after 2 weeks) and a third (after 4-6 weeks) OGTT was performed under treatment with mirtazapine. Compared to healthy controls, we observed significantly impaired glucose tolerance in acutely depressed patients. Effect size calculation indicated a moderate to large effects on glucose and insulin concentrations in response to an OGTT. Although glucose tolerance improved under mirtazapine treatment, insulin sensitivity was still impaired and remained significantly lower in patients compared to controls.