Treatment resistance in severe unipolar depression: no association with psychotic or melancholic features

BACKGROUND

Depressive subtypes generally have been neglected in research on treatment efficacy. We studied a sample of 699 severe unipolar depressed patients to detect any association between depressive features and treatment resistance.

METHODS

Participants were divided into psychotic (PSY, n = 90), melancholic (MEL, n = 430) and non-melancholic (n = 179) subjects according to clinical features. Formal diagnostic criteria (Mini International Neuropsychiatric Interview items), and items from 17-item Hamilton Rating Scale for Depression (HRSD17) were compared across groups. Non-responders were defined by a HRSD17 cut-off score of ≥17 after the last adequate antidepressant treatment. Treatment-resistant depression (TRD) was defined as the failure to respond to ≥2 adequate antidepressant trials. Non-linear regression models were designed to detect associations between depressive subtypes and TRD.

RESULTS

PSY and MEL patients appeared to be more severely affected and to share some "core" melancholic symptoms. Both PSY and MEL patients reported a higher rate of seasonality. However, we found no clinical or illness course variable associated with TRD.

CONCLUSIONS

Our results indicate that psychotic and melancholic depression share some "core" melancholia symptoms, while no distinguishing psychopathological feature appears to be associated with TRD in severely depressed patients.

Influence of family history of major depression, bipolar disorder, and suicide on clinical features in patients with major depression and bipolar disorder

The extent to which a family history of mood disorders and suicide could impact on clinical features of patients suffering from major depression (MD) and bipolar disorder (BD) has received relatively little attention so far. The aim of the present work is, therefore, to assess the clinical implications of the presence of at least one first- and/or second-degree relative with a history of MD, BD and suicide in a large sample of patients with MD or BD. One thousand one hundred and fifty-seven subjects with MD and 686 subjects with BD were recruited within the context of two large projects. The impact of a family history of MD, BD, and suicide-considered both separately and together-on clinical and socio-demographic variables was investigated. A family history of MD, BD, and suicide was more common in BD patients than in MD patients. A positive family history of mood disorders and/or suicide as well as a positive family history of MD and BD separately considered, but not a positive history of suicide alone, were significantly associated with a comorbidity with several anxiety disorders and inversely associated with age of onset. The clinical implications as well as the limitations of our findings are discussed.

The impact of adverse life events on clinical features and interaction with gene variants in mood disorder patients

BACKGROUND

Adverse life events are precipitating and maintenance factors for mood and anxiety disorders. However, the impact of such events on clinical features and treatment response is still unclear.

SAMPLING AND METHODS

The aim of this study was to investigate whether specific adverse events (early parental loss and physical abuse) influence clinical features in a sample of 1,336 mood disorder patients, and whether genetic parameters interact with adverse events to influence treatment outcomes in a subsample of 252 subjects. Participants were collected in the context of a European multicenter study and treated with antidepressants at adequate doses for at least 4 weeks. We focused on two genes (BDNF and CREB1) due to prior evidence of association with treatment outcomes in the same sample.

RESULTS

Patients with a history of physical abuse had higher suicidal risk (including history of attempts), comorbid panic disorder, posttraumatic stress disorder and alcohol dependence compared to non-abused patients. Experience of early parental loss was a less detrimental type of life stressor. Treatment response was not affected by adverse events. No gene-environment interaction was found with genetic variations, using a corrected significance level.

CONCLUSIONS

A limitation of the present study is that the subsample is too small for detecting gene-environment interactions. The clinical message of our findings is that mood disorder patients with a history of physical abuse showed a worse clinical profile, characterized by higher comorbid Axis I psychopathology and increased suicidal behavior.

Working memory-related functional brain patterns in never medicated children with ADHD

Attention Deficit/Hyperactivity Disorder (ADHD) is a pervasive neurodevelopmental disorder characterized by 3 clusters of age-inappropriate cardinal symptoms: inattention, hyperactivity and impulsivity. These clinical/behavioural symptoms are assumed to result from disturbances within brain systems supporting executive functions including working memory (WM), which refers to the ability to transiently store and flexibly manipulate task-relevant information. Ongoing or past medications, co-morbidity and differences in task performance are potential, independent confounds in assessing the integrity of cerebral patterns in ADHD. In the present study, we recorded WM-related cerebral activity during a memory updating N-back task using functional Magnetic Resonance Imaging (fMRI) in control children and never medicated, prepubescent children with ADHD but without comorbid symptoms. Despite similar updating performance than controls, children with ADHD exhibited decreased, below baseline WM-related activation levels in a widespread cortico-subcortical network encompassing bilateral occipital and inferior parietal areas, caudate nucleus, cerebellum and functionally connected brainstem nuclei. Distinctive functional connectivity patterns were also found in the ADHD in these regions, with a tighter coupling in the updating than in the control condition with a distributed WM-related cerebral network. Especially, cerebellum showed tighter coupling with activity in an area compatible with the brainstem red nucleus. These results in children with clinical core symptoms of ADHD but without comorbid affections and never treated with medication yield evidence for a core functional neuroanatomical network subtending WM-related processes in ADHD, which may participate to the pathophysiology and expression of clinical symptoms.

Rare copy number variants in neuropsychiatric disorders: Specific phenotype or not?

From a number of genome-wide association studies it was shown that de novo and/or rare copy number variants (CNVs) are found at an increased frequency in neuropsychiatric diseases. In this study we examined the prevalence of CNVs in six genomic regions (1q21.1, 2p16.3, 3q29, 15q11.2, 15q13.3, and 16p11.2) previously implicated in neuropsychiatric diseases. Hereto, a cohort of four neuropsychiatric disorders (schizophrenia, bipolar disorder, major depressive disorder, and intellectual disability) and control individuals from three different populations was used in combination with Multilpex Amplicon Quantifiaction (MAQ) assays, capable of high resolution (kb range) and custom-tailored CNV detection. Our results confirm the etiological candidacy of the six selected CNV regions for neuropsychiatric diseases. It is possible that CNVs in these regions can result in disturbed brain development and in this way lead to an increased susceptibility for different neuropsychiatric disorders, dependent on additional genetic and environmental factors. Our results also suggest that the neurodevelopmental component is larger in the etiology of schizophrenia and intellectual disability than in mood disorders. Finally, our data suggest that deletions are in general more pathogenic than duplications. Given the high frequency of the examined CNVs (1-2%) in patients of different neuropsychiatric disorders, screening of large cohorts with an affordable and feasible method like the MAQ assays used in this study is likely to result in important progress in unraveling the genetic factors leading to an increased susceptibility for several psychiatric disorders.

Non-random dropout and the relative efficacy of escitalopram and nortriptyline in treating major depressive disorder

Most comparisons of the efficacy of antidepressants have relied on the assumption that missing data are randomly distributed. Dropout rates differ between drugs, suggesting this assumption may not hold true. This paper examines the effect of non-random dropout on a comparison of two antidepressant drugs, escitalopram and nortriptyline, in the treatment of major depressive disorder. The GENDEP study followed adult patients with major depressive disorder over 12 weeks of treatment, and the primary analysis found no difference in efficacy of the two antidepressants under missing at random assumption. By applying the recently developed Muthén-Roy model, we compared the relative efficacy of these two antidepressants taking into account non-random distribution of missing outcomes (NMAR). Individuals who dropped out of the study were those who were not responding to treatment. Based on the best fitting NMAR model, it was found that escitalopram reduced symptom scores by an additional 1.4 points on the Montgomery-Åsberg Depression Rating Scale (p = 0.02), equivalent to 5% of baseline depression severity, compared to nortriptyline. We conclude that association between dropout and worsening symptoms led to an overestimate of the effectiveness of treatment, especially with nortriptyline, in the primary analysis. These findings review the primary analysis of GENDEP and suggest that, when non-random dropout is accounted for, escitalopram is more effective than nortriptyline in reducing symptoms of major depression.

Transcriptional profiles underlying vulnerability and resilience in rats exposed to an acute unavoidable stress

A complex interplay between gene and environment influences the vulnerability or the resilience to stressful events. In the acute escape deficit (AED) paradigm, rats exposed to an acute unavoidable stress (AUS) develop impaired reactivity to noxious stimuli. Here we assessed the behavioral and molecular changes in rats exposed to AUS. A genome-wide microarray experiment generated a comprehensive picture of changes in gene expression in the hippocampus and the frontal cortex of animals exposed or not to AUS. Exposure to AUS resulted in two distinct groups of rats with opposite behavioral profiles: one developing an AED, called "stress vulnerable," and one that did not develop an AED, called "stress resilient." Genome-wide profiling revealed a low percentage of overlapping mechanisms in the two areas, suggesting that, in the presence of stress, resilience or vulnerability to AUS is sustained by specific changes in gene expression that can either buffer or promote the behavioral and molecular adverse consequences of stress. Specifically, we observed in the frontal cortex a downregulation of the transcript coding for interferon-β and leukemia inhibitory factor in resilient rats and an upregulation of neuroendocrine related genes, growth hormone and prolactin, in vulnerable rats. In the hippocampus, the muscarinic M2 receptor was downregulated in vulnerable but upregulated in resilient rats. Our findings demonstrate that opposite behavioral responses did not correspond to opposite regulatory changes of the same genes, but resilience rather than vulnerability to stress was associated with specific changes, with little overlap, in the expression of patterns of genes.

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.

Identification of a CACNA2D4 deletion in late onset bipolar disorder patients and implications for the involvement of voltage-dependent calcium channels in psychiatric disorders

The GWAS-based association of CACNA1C with bipolar disorder (BPD) is one of the strongest genetic findings to date. CACNA1C belongs to the family of CACN genes encoding voltage-dependent calcium channels (VDCCs). VDCCs are involved in brain circuits and cognitive processes implicated in BPD and schizophrenia (SZ). Recently, it was shown that rare copy number variations (CNVs) are found at an increased frequency in SZ and to a lesser extent also in BPD, suggesting the involvement of CNVs in the causation of these diseases. We hypothesize that CNVs in CACN genes can influence the susceptibility to BPD, SZ, and/or schizoaffective disorder (SZA). A search for CNVs in eight CACN genes in a patient-control sample of European decent was performed. A total of 709 BP patients, 645 SZ patients, 189 SZA patients, and 1,470 control individuals were screened using the Multiplex Amplicon Quantification (MAQ) method. We found a rare, partial deletion of 35.7 kb in CACNA2D4 in two unrelated late onset bipolar I patients and in one control individual. All three deletions shared the same breakpoints removing exons 17-26 of CACNA2D4, comprising part of the CACHE domain. Based on the data we cannot claim causality to BPD of the identified CACNA2D4 deletion but nevertheless this deletion can be important in unraveling the underlying processes leading to psychiatric diseases in general and BPD in particular.

The impact of COMT gene polymorphisms on suicidality in treatment resistant major depressive disorder--a European multicenter study

Many association studies have reported associations between the catechol-O-methyltransferase (COMT) gene and psychiatric disorders including major depression (MDD). The COMT gene has further been associated with suicidal behaviour, as well as with treatment response, although with conflicting results. In the present study, we further elucidate the impact of COMT in treatment response in MDD patients with suicide risk and/or a personal history of suicide attempts. Two hundred fifty MDD patients were collected in the context of a European multicentre resistant depression study and treated with antidepressants at adequate doses for at least 4 weeks. Suicidality was assessed using Mini International Neuropsychiatric Interview (MINI) and the Hamilton Rating Scale for Depression (HAM-D). Treatment response was defined as HAM-D ≤ 17 and remission as HAM-D ≤ 7 after 4 weeks of treatment with antidepressants at adequate dose. Genotyping was performed for seven SNPs (rs4680, rs2075507, rs737865, rs6269, rs4633, rs4818 and rs165599) within the COMT gene. With regard to suicide risk and personal history of suicide attempts, neither single marker nor haplotypic association was found with any SNP after multiple testing correction. In non-responders, we found significant single marker and haplotypic association with suicide risk, but not in responders. The same holds true for both remitters and non-remitters, and when testing for association with a personal history of suicide attempts and treatment response phenotypes. In conclusion, we found significant association of COMT SNPs with suicide risk in MDD patients not responding to antidepressant treatment. Larger well-defined cohorts will be required to dissect this further.

CYP2C19 genotype predicts steady state escitalopram concentration in GENDEP

In vitro work shows CYP2C19 and CYP2D6 contribute to the metabolism of escitalopram to its primary metabolite, N-desmethylescitalopram. We report the effect of CYP2C19 and CYP2D6 genotypes on steady state morning concentrations of escitalopram and N-desmethylescitalopram and the ratio of this metabolite to the parent drug in 196 adult patients with depression in GENDEP, a clinical pharmacogenomic trial. Subjects who had one CYP2D6 allele associated with intermediate metabolizer phenotype and one associated with poor metabolizer (i.e. IM/PM genotypic category) had a higher mean logarithm escitalopram concentration than CYP2D6 extensive metabolizers (EMs) (p = 0.004). Older age was also associated with higher concentrations of escitalopram. Covarying for CYP2D6 and age, we found those homozygous for the CYP2C19*17 allele associated with ultrarapid metabolizer (UM) phenotype had a significantly lower mean escitalopram concentration (2-fold, p = 0.0001) and a higher mean metabolic ratio (p = 0.0003) than EMs, while those homozygous for alleles conferring the PM phenotype had a higher mean escitalopram concentration than EMs (1.55-fold, p = 0.008). There was a significant overall association between CYP2C19 genotypic category and escitalopram concentration (p = 0.0003; p = 0.0012 Bonferroni corrected). In conclusion, we have demonstrated an association between CYP2C19 genotype, including the CYP2C19*17 allele, and steady state escitalopram concentration.

Depression across mood disorders: review and analysis in a clinical sample

OBJECTIVES

In this article we aimed to: (1) review literature concerning the clinical and psychopathologic characteristics of Bipolar (BP) depression; (2) analyze an independent sample of depressed patients to identify any demographic and/or clinical feature that may help in differentiating mood disorder subtypes, with special attention to potential markers of bipolarity.

METHODS

A sample of 291 depressed subjects, including BP -I (n = 104), BP -II (n = 64), and unipolar (UP) subjects with (n = 53) and without (n = 70) BP family history (BPFH), was examined to evidence potential differences in clinical presentation and to validate literature-derived markers of bipolarity. Demographic and clinical variables and, also, single items from the Hamilton Depression Rating Scale (HDRS), the Montgomery-Asberg Depression Rating Scale (MADRS), and the Young Mania Rating Scale (YMRS) were compared among groups.

RESULTS

UP subjects had an older age at onset of mood symptoms. A higher number of major depressive episodes and a higher incidence of lifetime psychotic features were found in BP subjects. Items expressing depressed mood, depressive anhedonia, pessimistic thoughts, and neurovegetative symptoms of depression scored higher in UP, whereas depersonalization and paranoid symptoms' scores were higher in BP. When compared with UP, BP I had a significantly higher incidence of intradepressive hypomanic symptoms. Bipolar family history was found to be the strongest predictor of bipolarity in depression.

CONCLUSIONS

Overall, our findings confirm most of the classical signs of bipolarity in depression and support the view that some features, such as BPFH, together with some specific symptoms may help in detecting depressed subjects at higher risk for BP disorder.

Phenomenology of psychotic mood disorders: lifetime and major depressive episode features

BACKGROUND

The nosological and clinical implications of psychotic features in the course of mood disorders have been widely debated. Currently, no specification exists for defining a subgroup of lifetime Psychotic Mood Disorder (PMD) patients.

METHODS

A total of 2178 patients were examined, including subjects with Bipolar Disorder (BP) type I (n=519) and II (n=207) and Major Depressive Disorder (n=1452). Patients were divided between PMD (n=645) and non-psychotic Mood Disorders (MD) (n=1533) by the lifetime presence of at least one mood episode with psychotic features. Subjects having a depressive episode at the time of assessment were also examined: HAM-D and YMRS scores were compared between MD and PMD subjects, both with and without current psychotic features.

RESULTS

A diagnosis of BP-I, a higher familial load for BP, a higher number of mood episodes lifetime, and a higher prevalence of OCD and somatic comorbidities were all associated to PMD. A diagnosis of BP (OR=4.48) was the only significant predictor for psychosis. PMD with non-psychotic depression were apparently less severe than MD patients and had a lower rate of "non-responders" to AD treatment. Sub-threshold manic symptoms and suicidal risk were also more pronounced among PMD.

LIMITATIONS

The lack of information about number and polarity of previous psychotic mood episodes may be the major limitations of our study.

CONCLUSIONS

BP diagnosis is the most significant predictor for psychosis in mood disorders. Non-psychotic mood episodes in PMD patients may be characterized by a distinctive symptom profile and, possibly, a different response to treatment.

Early and delayed onset of response to antidepressants in individual trajectories of change during treatment of major depression: a secondary analysis of data from the Genome-Based Therapeutic Drugs for Depression (GENDEP) study

OBJECTIVE

The timing and rate of improvement after the initiation of an antidepressant has implications for establishing the mechanism of antidepressant action and for answering the clinically relevant question of how long an appropriate trial of antidepressant medication should be. We explore the individual trajectories of relative change in depression severity to establish what proportion of individuals experience early and late onset of improvement.

METHOD

Longitudinal latent class analysis was applied in a secondary analysis of data obtained from the Genome-Based Therapeutic Drugs for Depression (GENDEP) study. In the GENDEP trial, conducted in 9 European academic psychiatry centers from July 2004 to June 2008, 811 treatment-seeking adult subjects with DSM-IV major depression received escitalopram or nortriptyline for 12 weeks. Montgomery-Asberg Depression Rating Scale measurements were taken weekly. The secondary analysis reported in this article was conducted in 2010.

RESULTS

A model with 9 latent classes provided a good description of the individual trajectories of symptom change over time. These classes included 3 nonresponder classes, 3 classes with varying degrees of improvement concentrated in the first 3 weeks (early improvement), and 3 classes with varying degrees of improvement that was more prominent in the second 3 weeks than in the first 3 weeks (delayed improvement). More than half of the subjects who eventually reached remission showed a pattern of delayed improvement, and their eventual outcome could not be predicted from early time points. Early marked response occurred more frequently in subjects treated with nortriptyline than in those treated with escitalopram (12.9% vs 7.5%, χ² = 6.29, P = .01). Delayed complete remission occurred more frequently in subjects treated with escitalopram than in those treated with nortriptyline (13.6% vs 6.1%, χ² = 11.52, P = .0007).

CONCLUSIONS

Both early and delayed improvement are common. Although early changes are maintained, the eventual outcome of 12-week antidepressant treatment can be accurately predicted only after 8 weeks.

TRIAL REGISTRATION

http://www.controlled-trials.com Identifier: ISRCTN03693000.

Citalopram versus desipramine in treatment resistant depression: effect of continuation or switching strategies: a randomized open study

OBJECTIVES. Evidence in favour of switching between selective serotonin reuptake inhibitor (SSRI) and tricyclic (TCA) antidepressants in treatment resistant depression has been tested in a few studies only, consequently a prospective study was undertaken to evaluate the impact of switching strategies. METHODS. One hundred eighty-nine patients who failed to respond to a previous antidepressant were randomised to four arms: firstly they received citalopram or desipramine for a 4-week period; secondly, those who failed to respond were treated for a further 4-week period with the same antidepressant (citalopram-citalopram and desipramine-desipramine arms) or switched to the alternate one (citalopram-desipramine and desipramine-citalopram arms). RESULTS. There was no difference in the first 4-week phase between patients receiving citalopram versus desipramine in Hamilton Rating Scale for Depression (HRSD), Montgomery-Asberg Depression Rating Scale (MADRS), and Clinical Global Impression (CGI) scores. In the second 4-week phase remitter rates were higher among non-switched patients (P = 0.04). Moreover, considering HRSD and MADRS, switched patients reported significantly higher scores (P ≤ 0.02 for both scales at each time-point). CONCLUSIONS. This study supports the thesis that switching from an SSRI to a TCA (and vice versa) in non-responders to a 4-week trial of an SSRI/TCA is not associated with improved response. The result goes in the opposite direction to that predicted by current guidelines.

Melancholic, atypical and anxious depression subtypes and outcome of treatment with escitalopram and nortriptyline

OBJECTIVE

To investigate whether subtypes of depression predict differential outcomes of treatment with selective serotonin-reuptake inhibitor (SSRI) and a tricyclic antidepressant in major depression.

METHOD

Among 811 adults with moderate-to-severe depression, melancholic, atypical, anxious and anxious-somatizing depression subtypes established at baseline were evaluated as predictors of outcome of treatment with flexible dosage of the SSRI escitalopram or the tricyclic antidepressant nortriptyline. The primary outcome measure was the Montgomery-Åsberg Depression Rating Scale (MADRS). Secondary outcome measures were the 17-item Hamilton Rating Scale for Depression (HRSD-17) and the Beck Depression Inventory (BDI).

RESULTS

Melancholic depression was associated with slightly worse outcomes among individuals treated with escitalopram, but did not affect outcome of treatment with nortriptyline. The interaction between melancholic depression and drug did not reach statistical significance for the primary outcome measure and significant results for secondary outcome measures were not robust in sensitivity analyses. Atypical depression was unrelated to outcome of treatment with either antidepressant. Anxious and anxious-somatizing depression did not predict outcome on the primary measure, but inconsistently predicted worse outcome in some secondary analyses.

LIMITATIONS

Some participants were non-randomly allocated to drug. Therefore, drug-by-predictor interactions had to be validated in sensitivity analyses restricted to the 468 randomly allocated individuals.

CONCLUSIONS

Melancholic, atypical or anxious depression, are not sufficiently robust differential predictors of outcome to help clinician choose between SSRI and tricyclic antidepressants. There is a need to investigate other predictors of outcome.

Variation in GNB3 predicts response and adverse reactions to antidepressants

There is substantial inter-individual variation in response and adverse reactions to antidepressants, and genetic variation may, in part, explain these differences. GNB3 encodes the β3 subunit of the G protein complex, which is involved in the downstream signalling cascade following monoamine receptor activation. A functional polymorphism in this gene (C825T) has been associated with response to antidepressants. Several lines of evidence suggest that GNB3 moderates improvement in the neurovegetative symptoms of depression (such as sleep and appetite) and related adverse reactions independently of change in core mood symptoms. We here report analysis of data from GENDEP, a part-randomized pharmacogenomic trial, on the outcome of 811 subjects with major depression undergoing treatment with either escitalopram or nortriptyline in which the C825T SNP and three further SNPs in GNB3 were genotyped. The TT genotype was significantly associated with a superior response to nortriptyline and these effects were specific to improvements in neurovegetative symptoms. In addition, the same genotype predicted fewer incidents of treatment-emergent insomnia and greater weight gain on the same drug. Our results are consistent with previous associations with GNB3 and emphasize the importance of signalling genes in antidepressant response.

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.

FC04-06 - Candidate gene association study of suicidality in treatment resistant MDD

Suicidal behaviour runs in families and the existence of genetic vulnerability to suicidality is well-established. Mental disorders, especially depression, are present in more of 90% of suicides. The incidence of treatment emergent suicidal ideation in major depression (MDD) varies from 4% to 20%, depending on the definition of suicidal ideation and sample characteristics.

In the present study, we further elucidated the impact of depression candidate genes in treatment emergent suicidal ideation in MDD. One hundred-seventy MDD patients were collected in the context of a resistant depression study and treated with antidepressants at adequate doses for at least 4 weeks. MDD subjects were genotyped for SNPs within the COMT gene, BDNF, DTNBP1, 5HT1A, 5HT2A, GNB3, GRIK4, PTGS1, PTGS2, CREB, and cytochrome P450 CYP1A2, CYP2C9, CYP2C19 and CYP2D6 gene. Response, remission and treatment resistance, as well as suicidality information derived from Mini International Neuropsychiatric Interview (MINI) and Hamilton Rating Scale for Depression (HAM-D) were recorded.

A quantitative and measure of suicidal behaviour was defined using the Hamilton rating scale (score 0 to 4) and the MINI-item (yes/no) on suicidality in a large cohort of depression cases. In addition, we tested for association with ‘serious suicidal attempts’ corresponding to a HAMD score of 4 (discrete trait analyses). Results of this candidate gene approach in treatment emergent suicidal ideation in MDD will be presented and discussed.

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.

Stressful life events, cognitive symptoms of depression and response to antidepressants in GENDEP

BACKGROUND

The occurrence of stressful life events (SLEs) has been shown to predict response to antidepressants; however, results are inconsistent. There is some evidence to suggest that SLEs prior to treatment are associated with greater cognitive symptoms at baseline and may therefore predict changes in these symptoms specifically.

METHODS

GENDEP, a prospective part-randomised pharmacogenomics trial, collected longitudinal data on the symptoms of patients with major depression treated with either a selective serotonin reuptake inhibitor (SSRI, escitalopram) or a tricyclic antidepressant (TCA, nortriptyline). Data on life events experienced in the 6 months preceding treatment measured using the List of Threatening Experiences Questionnaire (LTE-Q) were available for 728 participants.

RESULTS

Both the occurrence and number of SLEs were associated with greater cognitive but not mood or neurovegetative symptoms prior to treatment. Those who reported SLEs also experienced a greater decline in cognitive symptoms during treatment with escitalopram, but not with nortriptyline.

LIMITATIONS

Life events were measured retrospectively using a self-report checklist and are therefore subject to a number of biases especially in the context of depressive illness.

CONCLUSIONS

These findings are in line with cognitive theories of depression and suggest that symptomatic heterogeneity may have contributed to inconsistencies in studies reported to date. Our results also tentatively suggest a clinically relevant drug specific effect of SLEs. Specifically, those reporting stress may benefit more from treatment with SSRIs than TCAs.

Dysbindin gene (DTNBP1) in major depressive disorder (MDD) patients: lack of association with clinical phenotypes

OBJECTIVES

Dystrobrevin binding protein 1 (Dysbindin) is a plausible candidate gene for major depressive disorders (MDD) due to its involvement in synaptic signaling, plasticity and localization in the brain.

METHODS

Two intronic SNPs of DTNBP1; rs760761 (P1320) and rs2619522 (P1763) were analyzed in 206 patients with DSM-IV MDD to investigate the functional impact of genotypes on susceptibility for depression and some clinical phenotypes. The Sequenom iPLEX assay (Sequenom, Cambridge, MA) was used for genotyping.

RESULTS AND CONCLUSIONS

Despite the limited power of analysis, our results showed that these two SNPs in DTNPB1 gene were not related to clinical phenotypes such as melancholia, age at onset, suicidality and co-morbid anxiety disorders, as well as to treatment response phenotypes.