Why do we need new and better antidepressants?

Antidepressants and Circadian Rhythm: Exploring Their Bidirectional Interaction for the Treatment of Depression

Scientific evidence that circadian rhythms affect pharmacokinetics and pharmacodynamics has highlighted the importance of drug dosing-time. Circadian oscillations alter drug absorption, distribution, metabolism, and excretion (ADME) as well as intracellular signaling systems, target molecules (e.g., receptors, transporters, and enzymes), and gene transcription. Although several antidepressant drugs are clinically available, less than 50% of depressed patients respond to first-line pharmacological treatments. Chronotherapeutic approaches to enhance the effectiveness of antidepressants are not completely known. Even so, experimental results found until this day suggest a positive influence of drug dosing-time on the efficacy of depression therapy. On the other hand, antidepressants have also demonstrated to modulate circadian rhythmicity and sleep-wake cycles. This review aims to evidence the potential of chronotherapy to improve the efficacy and/or safety of antidepressants. It includes pre-clinical and clinical studies that demonstrate the relevance of determining the most appropriate time of administration for antidepressant drugs. In parallel, their positive influence on the resynchronization of disrupted circadian rhythms is also herein discussed. It is expected that this review will promote the investigation of chronotherapy for the treatment of depression, contribute to a better understanding of the relationship between antidepressants and circadian rhythms, and consequently promote the development of new therapeutics.

Ursolic acid enhances stress resistance, reduces ROS accumulation and prolongs life span in C. elegans serotonin-deficient mutants

INTRODUCTION

Depression and anxiety disorders contribute to the global disease burden. Ursolic acid (UA), a natural compound present in many vegetables, fruits and medicinal plants, was tested in vivo for its effect on (1) enhancing resistance to stress and (2) its effect on life span.

METHODS

The compound was tested for its antioxidant activity in C. elegans. Stress resistance was tested in the heat and osmotic stress assay. Additionally, the influence on normal life span was examined. RT-PCR was used to assess possible serotonin targets.

RESULTS

UA prolonged the life span of C. elegans. Additionally, UA significantly lowered reactive oxygen species (ROS). Molecular docking studies, PCR analysis and microscale thermophoresis (MST) supported the results that UA acts through serotonin receptors to enhance stress resistance.

DISCUSSION

Considering the urgent need for new and safe medications in the treatment of depression and anxiety disorders, our results indicate that UA may be a promising new drug candidate.

Differentiating Melancholic and Non-melancholic Major Depressive Disorder Using Fractional Amplitude of Low-Frequency Fluctuations

BACKGROUND

Melancholic major depressive disorder (MDD) is a network-based brain disorder. However, whether or not network-based changes can be applied to differentiate melancholic (MEL) from non-melancholic (NMEL) MDD remains unclear.

METHODS

Thirty-one MEL patients, 28 NMEL patients, and 32 matched healthy controls (HCs) were scanned using resting-state functional magnetic resonance imaging. Patients were assessed by the Chinese version of Snaith-Hamilton Pleasure Scale (SHAPS-C) and Temporal Experience of Pleasure Scale (TEPS). Fractional amplitude of low-frequency fluctuations (fALFF) and correlation analysis were used to analyze the data.

RESULTS

Compared with HCs, the MEL group had significantly higher fALFF values in the bilateral inferior frontal gyrus and right supplementary motor area (SMA) and significantly lower fALFF values in the right inferior occipital gyrus (IOG), right middle temporal gyrus (MTG)/left IOG, and bilateral superior occipital gyrus (SOG)/MTG. On the other hand, the NMEL group showed significantly higher fALFF values in the bilateral SMA and significantly lower fALFF values in the bilateral posterior cingulate cortex/precuneus relative to HCs. Compared with the NMEL group, the MEL group showed significantly lower fALFF values in the left anterior cingulate cortex (ACC). A correlation was found between the fALFF values of the right SMA and the SHAPS-C in the MEL group. In addition, correlations were observed between the fALFF values of the left ACC and the TEPS contextual consummatory and total scores in all patients.

CONCLUSION

Our study uncovered that MDD exhibited altered brain activity in extensive brain networks, including the default-mode network, frontal-striatal network, reward system, and frontal-limbic network. Decreased fALFF in the left ACC might be applied to differentiate the two subtypes of MDD.

Novel Aryloxyethyl Derivatives of 1-(1-Benzoylpiperidin-4-yl)methanamine as the Extracellular Regulated Kinases 1/2 (ERK1/2) Phosphorylation-Preferring Serotonin 5-HT1A Receptor-Biased Agonists with Robust Antidepressant-like Activity

Novel 1-(1-benzoylpiperidin-4-yl)methanamine derivatives were designed as "biased agonists" of serotonin 5-HT_1A receptors. The compounds were tested in signal transduction assays (ERK1/2 phosphorylation, cAMP inhibition, Ca²⁺ mobilization, and β-arrestin recruitment) which identified ERK1/2 phosphorylation-preferring aryloxyethyl derivatives. The novel series showed high 5-HT_1A receptor affinity, >1000-fold selectivity versus noradrenergic α₁, dopamine D₂, serotonin 5-HT_2A, histamine H₁, and muscarinic M₁ receptors, and favorable druglike properties (CNS-MPO, Fsp³, LELP). The lead structure, (3-chloro-4-fluorophenyl)(4-fluoro-4-(((2-(pyridin-2-yloxy)ethyl)amino)methyl)piperidin-1-yl)methanone (17, NLX-204), displayed high selectivity in the SafetyScreen44 panel (including hERG channel), high solubility, metabolic stability, and Caco-2 penetration and did not block CYP3A4, CYP2D6 isoenzymes, or P-glycoprotein. Preliminary in vivo studies confirmed its promising pharmacokinetic profile. 17 also robustly stimulated ERK1/2 phosphorylation in rat cortex and showed highly potent (MED = 0.16 mg/kg) and efficacious antidepressant-like activity, totally eliminating immobility in the rat Porsolt test. These data suggest that the present 5-HT_1A receptor-biased agonists could constitute promising antidepressant drug candidates.

Neuropeptide and Small Transmitter Coexistence: Fundamental Studies and Relevance to Mental Illness

Neuropeptides are auxiliary messenger molecules that always co-exist in nerve cells with one or more small molecule (classic) neurotransmitters. Neuropeptides act both as transmitters and trophic factors, and play a role particularly when the nervous system is challenged, as by injury, pain or stress. Here neuropeptides and coexistence in mammals are reviewed, but with special focus on the 29/30 amino acid galanin and its three receptors GalR1, -R2 and -R3. In particular, galanin's role as a co-transmitter in both rodent and human noradrenergic locus coeruleus (LC) neurons is addressed. Extensive experimental animal data strongly suggest a role for the galanin system in depression-like behavior. The translational potential of these results was tested by studying the galanin system in postmortem human brains, first in normal brains, and then in a comparison of five regions of brains obtained from depressed people who committed suicide, and from matched controls. The distribution of galanin and the four galanin system transcripts in the normal human brain was determined, and selective and parallel changes in levels of transcripts and DNA methylation for galanin and its three receptors were assessed in depressed patients who committed suicide: upregulation of transcripts, e.g., for galanin and GalR3 in LC, paralleled by a decrease in DNA methylation, suggesting involvement of epigenetic mechanisms. It is hypothesized that, when exposed to severe stress, the noradrenergic LC neurons fire in bursts and release galanin from their soma/dendrites. Galanin then acts on somato-dendritic, inhibitory galanin autoreceptors, opening potassium channels and inhibiting firing. The purpose of these autoreceptors is to act as a 'brake' to prevent overexcitation, a brake that is also part of resilience to stress that protects against depression. Depression then arises when the inhibition is too strong and long lasting - a maladaption, allostatic load, leading to depletion of NA levels in the forebrain. It is suggested that disinhibition by a galanin antagonist may have antidepressant activity by restoring forebrain NA levels. A role of galanin in depression is also supported by a recent candidate gene study, showing that variants in genes for galanin and its three receptors confer increased risk of depression and anxiety in people who experienced childhood adversity or recent negative life events. In summary, galanin, a neuropeptide coexisting in LC neurons, may participate in the mechanism underlying resilience against a serious and common disorder, MDD. Existing and further results may lead to an increased understanding of how this illness develops, which in turn could provide a basis for its treatment.

Gender differences in quality of life and functional disability for depression outpatients with or without residual symptoms after acute phase treatment in China

BACKGROUND

Depression is associated with substantial personal suffering and reduced quality of life and functioning. The aim of this study was to investigate gender differences on quality of life and functional impairment of outpatients with depression after acute phase treatment.

METHODS

1503 depression outpatients were recruited from eleven hospitals in China. Subjects were evaluated with sociodemographic characteristics, history and self-report instruments, related to severity of symptoms, function and quality of life. All data were analyzed to determine the gender differences.

RESULTS

Men had a younger age at onset and the first onset age, higher education compared to women in total patients and with or without residual symptoms group. Using regression analysis, it was found that gender was significantly statistically related to severity scores of SDS and had no correlation with Q-LES-Q-SF total scores. In the residual symptoms group, greater functional impairment was noted by men in the area of work and social life. Significant gender differences of mood, work and sexual life in quality of life were observed.

LIMITATIONS

This is a cross-sectional study of depressed outpatients and duration of acute phase treatment may not an adequate time to measure changes.

CONCLUSIONS

Depression appears to affect men more seriously than women after acute phase treatment. Men had a younger age at onset and the first onset age, higher education, more functional impairment and lower satisfaction of quality of life in mood, work and sexual life. Gender differences affect acute treatment, remission and recovery.

A critical review of trials of transcranial direct current stimulation and trigeminal nerve stimulation for depression: the issue of treatment-emergent mania

Objective:

This study is a critical review analyzing occurrence of treatment-emergent mania (TEM) related to transcranial direct current stimulation (tDCS) and trigeminal nerve stimulation (TNS).

Method:

We present a systematic review of the literature on TEM related to tDCS and TNS treatment for major depressive disorder (MDD), conducted in accordance with the recommendations from Cochrane Group and the PRISMA guidelines.

Results:

Our search identified few reported episodes of TEM in the literature. In fact, we found 11 trials focused on treatment of MDD (seven controlled trials of tDCS and four trials of TNS, three open label and one controlled). We highlight the need for safety assessment in clinical research settings to establish with precision and in larger samples the risks inherent to the technique under investigation.

Conclusion:

Safety assessment is of fundamental importance in clinical research. TEM is a very important safety issue in MDD trials. Further and larger controlled trials will help to clarify both the safety and the clinical effects of combinations of pharmacotherapy and tDCS or TNS in daily clinical practice.

Alterations in the neuropeptide galanin system in major depressive disorder involve levels of transcripts, methylation, and peptide

Major depressive disorder (MDD) is a substantial burden to patients, families, and society, but many patients cannot be treated adequately. Rodent experiments suggest that the neuropeptide galanin (GAL) and its three G protein-coupled receptors, GAL_1-3, are involved in mood regulation. To explore the translational potential of these results, we assessed the transcript levels (by quantitative PCR), DNA methylation status (by bisulfite pyrosequencing), and GAL peptide by RIA of the GAL system in postmortem brains from depressed persons who had committed suicide and controls. Transcripts for all four members were detected and showed marked regional variations, GAL and galanin receptor 1 (GALR1) being most abundant. Striking increases in GAL and GALR3 mRNA levels, especially in the noradrenergic locus coeruleus and the dorsal raphe nucleus, in parallel with decreased DNA methylation, were found in both male and female suicide subjects as compared with controls. In contrast, GAL and GALR3 transcript levels were decreased, GALR1 was increased, and DNA methylation was increased in the dorsolateral prefrontal cortex of male suicide subjects, however, there were no changes in the anterior cingulate cortex. Thus, GAL and its receptor GALR3 are differentially methylated and expressed in brains of MDD subjects in a region- and sex-specific manner. Such an epigenetic modification in GALR3, a hyperpolarizing receptor, might contribute to the dysregulation of noradrenergic and serotonergic neurons implicated in the pathogenesis of MDD. Thus, one may speculate that a GAL₃ antagonist could have antidepressant properties by disinhibiting the firing of these neurons, resulting in increased release of noradrenaline and serotonin in forebrain areas involved in mood regulation.

Safety and tolerability of vortioxetine (15 and 20 mg) in patients with major depressive disorder: results of an open-label, flexible-dose, 52-week extension study

Vortioxetine is approved for the treatment of adults with major depressive disorder. This open-label extension (OLE) study evaluated the safety and tolerability of vortioxetine in the long-term treatment of major depressive disorder patients, as well as evaluated its effectiveness using measures of depression, anxiety, and overall functioning. This was a 52-week, flexible-dose, OLE study in patients who completed one of three randomized, double-blind, placebo-controlled, 8-week vortioxetine trials. All patients were switched to 10 mg/day vortioxetine for week 1, then adjusted between 15 and 20 mg for the remainder of the study, but not downtitrated below 15 mg. Safety and tolerability were assessed on the basis of treatment-emergent adverse events (TEAEs), vital signs, laboratory values, physical examination, and the Columbia-Suicide Severity Rating Scale. Efficacy measures included the Montgomery-Åsberg Depression Rating Scale, the Hamilton Anxiety Scale, the Clinical Global Impression Scale-Severity of Illness, and the Sheehan Disability Scale. Of the 1075 patients enrolled, 1073 received at least one dose of vortioxetine and 538 (50.0%) completed the study. A total of 537 patients withdrew early, with 115 (10.7% of the original study population) withdrawing because of TEAEs. Long-term treatment with vortioxetine was well tolerated; the most common TEAEs (≥10%) were nausea and headache. Laboratory values, vital signs, and physical examinations revealed no trends of clinical concern. The mean Montgomery-Åsberg Depression Rating Scale total score was 19.9 at the start of the extension study and 9.0 after 52 weeks of treatment (observed cases). Similar improvements were observed with the Hamilton Anxiety Scale (Δ-4.2), the Clinical Global Impression Scale-Severity of Illness (Δ-1.2), and the Sheehan Disability Scale (Δ-4.7) total scores after 52 weeks of treatment (observed case). In this 52-week, flexible-dose OLE study, 15 and 20 mg vortioxetine were safe and well tolerated. After entry into this study, patients continued to show improvement in depression and anxiety symptoms, as well as overall functioning, throughout the treatment period.

Natural polyphenols in the management of major depression

INTRODUCTION

Natural polyphenols, the non-essential micronutrients, found in array of plant products, are known to affect various physiological and biochemical functions in the body. Studies have shown the protective effect of these polyphenols in different neurological and mental disorders. These polyphenols modulate monoaminergic neurotransmission in the brain and thus possess antidepressant-like activity at least in animal models of depression.

AREAS COVERED

The present review discusses the use of these natural polyphenols in the treatment of major depression. The review article discusses the antidepressant potential of some important polyphenols such as amentoflavone, apigenin, chlorogenic acid, curcumin, ferulic acid, hesperidin, rutin, quercetin, naringenin, resveratrol, ellagic acid, nobiletin and proanthocyanidins. The mechanism of action of these polyphenols in the treatment of major depression is also discussed in detail.

EXPERT OPINION

There is an exciting prospect in the discovery of natural polyphenols as therapeutic agents in the treatment of major depression.

Distinct features of neurotransmitter systems in the human brain with focus on the galanin system in locus coeruleus and dorsal raphe

Using riboprobe in situ hybridization, we studied the localization of the transcripts for the neuropeptide galanin and its receptors (GalR1-R3), tryptophan hydroxylase 2, tyrosine hydroxylase, and nitric oxide synthase as well as the three vesicular glutamate transporters (VGLUT 1-3) in the locus coeruleus (LC) and the dorsal raphe nucleus (DRN) regions of postmortem human brains. Quantitative real-time PCR (qPCR) was used also. Galanin and GalR3 mRNA were found in many noradrenergic LC neurons, and GalR3 overlapped with serotonin neurons in the DRN. The qPCR analysis at the LC level ranked the transcripts in the following order in the LC: galanin >> GalR3 >> GalR1 > GalR2; in the DRN the ranking was galanin >> GalR3 >> GalR1 = GalR2. In forebrain regions the ranking was GalR1 > galanin > GalR2. VGLUT1 and -2 were strongly expressed in the pontine nuclei but could not be detected in LC or serotonin neurons. VGLUT2 transcripts were found in very small, nonpigmented cells in the LC and in the lateral and dorsal aspects of the periaqueductal central gray. Nitric oxide synthase was not detected in serotonin neurons. These findings show distinct differences between the human brain and rodents, especially rat, in the distribution of the galanin system and some other transmitter systems. For example, GalR3 seems to be the important galanin receptor in both the human LC and DRN versus GalR1 and -2 in the rodent brain. Such knowledge may be important when considering therapeutic principles and drug development.

Adjunctive agomelatine therapy in the treatment of acute bipolar II depression: a preliminary open label study

PURPOSE

The circadian rhythm hypothesis of bipolar disorder (BD) suggests a role for melatonin in regulating mood, thus extending the interest toward the melatonergic antidepressant agomelatine as well as type I (acute) or II cases of bipolar depression.

PATIENTS AND METHODS

Twenty-eight depressed BD-II patients received open label agomelatine (25 mg/bedtime) for 6 consecutive weeks as an adjunct to treatment with lithium or valproate, followed by an optional treatment extension of 30 weeks. Measures included the Hamilton depression scale, Pittsburgh Sleep Quality Index, the Clinical Global Impression Scale-Bipolar Version, Young Mania Rating Scale, and body mass index.

RESULTS

Intent to treat analysis results demonstrated that 18 of the 28 subjects (64%) showed medication response after 6 weeks (primary study endpoint), while 24 of the 28 subjects (86%) responded by 36 weeks. When examining primary mood stabilizer treatment, 12 of the 17 (70.6%) valproate and six of the 11 (54.5%) lithium patients responded by the first endpoint. At 36 weeks, 14 valproate treated (82.4%) and 10 lithium treated (90.9%) subjects responded. At 36 weeks, there was a slight yet statistically significant (P = 0.001) reduction in body mass index and Pittsburgh Sleep Quality Index scores compared to respective baseline values, regardless of mood stabilizer/outcome. Treatment related drop-out cases included four patients (14.28%) at week 6 two valproate-treated subjects with pseudo-vertigo and drug-induced hypomania, respectively, and two lithium-treated subjects with insomnia and mania, respectively. Week 36 drop outs were two hypomanic cases, one per group.

CONCLUSION

Agomelatine 25 mg/day was an effective and well-tolerated adjunct to valproate/lithium for acute depression in BD-II, suggesting the need for confirmation by future double blind, controlled clinical trials.

Resting-state functional connectivity bias of middle temporal gyrus and caudate with altered gray matter volume in major depression

Magnetic resonance imaging (MRI) studies have indicated that the structure deficits and resting-state functional connectivity (FC) imbalances in cortico-limbic circuitry might underline the pathophysiology of MDD. Using structure and functional MRI, our aim is to investigate gray matter abnormalities in patients with treatment-resistant depression (TRD) and treatment-responsive depression (TSD), and test whether the altered gray matter is associated with altered FC. Voxel-based morphometry was used to investigate the regions with gray matter abnormality and FC analysis was further conducted between each gray matter abnormal region and the remaining voxels in the brain. Using one-way analysis of variance, we found significant gray matter abnormalities in the right middle temporal cortex (MTG) and bilateral caudate among the TRD, TSD and healthy controls. For the FC of the right MTG, we found that both the patients with TRD and TSD showed altered connectivity mainly in the default-mode network (DMN). For the FC of the right caudate, both patient groups showed altered connectivity in the frontal regions. Our results revealed the gray matter reduction of right MTG and bilateral caudate, and disrupted functional connection to widely distributed circuitry in DMN and frontal regions, respectively. These results suggest that the abnormal DMN and reward circuit activity might be biomarkers of depression trait.

Emotional memory impairments in a genetic rat model of depression: involvement of 5-HT/MEK/Arc signaling in restoration

Cognitive dysfunctions are common in major depressive disorder, but have been difficult to recapitulate in animal models. This study shows that Flinders sensitive line (FSL) rats, a genetic rat model of depression, display a pronounced impairment of emotional memory function in the passive avoidance (PA) task, accompanied by reduced transcription of Arc in prefrontal cortex and hippocampus. At the cellular level, FSL rats have selective reductions in levels of NMDA receptor subunits, serotonin 5-HT(1A) receptors and MEK activity. Treatment with chronic escitalopram, but not with an antidepressant regimen of nortriptyline, restored memory performance and increased Arc transcription in FSL rats. Multiple pharmacological manipulations demonstrated that procognitive effects could also be achieved by either disinhibition of 5-HT(1A)R/MEK/Arc or stimulation of 5-HT₄R/MEK/Arc signaling cascades. Taken together, studies of FSL rats in the PA task revealed reversible deficits in emotional memory processing, providing a potential model with predictive and construct validity for assessments of procognitive actions of antidepressant drug therapies.

Abnormal neural activities in first-episode, treatment-naïve, short-illness-duration, and treatment-response patients with major depressive disorder: a resting-state fMRI study

BACKGROUND

Abnormality of limbic-cortical networks was postulated in depression. Using a regional homogeneity (ReHo) approach, we explored the regional homogeneity (ReHo) of the brain regions in patients with first-episode, treatment-naïve, short-illness-duration, and treatment-response depression in resting state to test the abnormality hypothesis of limbic-cortical networks in major depressive disorder (MDD).

METHODS

Seventeen patients with treatment-response MDD and 17 gender-, age-, and education-matched healthy subjects participated in the resting-state fMRI scans.

CONCLUSIONS

Our findings suggested the abnormality of limbic-cortical networks in first-episode, treatment-naïve, short-illness-duration, and treatment-response MDD patients, and added an expanding literature to the abnormality hypothesis of limbic-cortical networks in MDD.

Disrupted regional homogeneity in treatment-resistant depression: a resting-state fMRI study

BACKGROUND

Using a newly developed regional homogeneity (ReHo) approach, we were to explore the features of brain activity in patients with treatment-resistant depression (TRD) in resting state, and further to examine the relationship between abnormal brain activity in TRD patients and specific symptom factors derived from ratings on the Hamilton Rating Scale for Depression (HRSD).

METHODS

24 patients with TRD and 19 gender-, age-, and education-matched healthy subjects participated in the fMRI scans.

RESULTS

1. Compared with healthy controls, decreased ReHo were found in TRD patients in the left insula, superior temporal gyrus, inferior frontal gyrus, lingual gyrus and cerebellumanterior lobe (culmen) (p<0.05, corrected). 2. Compared with healthy controls, increased ReHo were found in the left superior temporal gyrus, cerebellum posterior lobe (tuber), cerebellum anterior lobe (culmen), the right cerebellar tonsil and bilateral fusiform gyrus (p<0.05, corrected). 3. There was no correlation between the ReHo values in any brain region detected in our study and the patients' age, years of education, illness duration, HRSD total score and its symptom factors.

LIMITATION

The influence of antidepressants to the brain activity in TRD patients was not fully eliminated.

CONCLUSIONS

The pathogenesis of TRD may be attributed to abnormal neural activity in multiple brain regions.

Escitalopram modulates neuron-remodelling proteins in a rat gene-environment interaction model of depression as revealed by proteomics. Part I: genetic background

The wide-scale analysis of protein expression provides a powerful strategy for the molecular exploration of complex pathophysiological mechanisms, such as the response to antidepressants. Using a 2D proteomic approach we investigated the Flinders Sensitive Line (FSL), a genetically selected rat model of depression, and the control Flinders Resistant Line (FRL). To evaluate gene-environment interactions, FSL and FRL pups were separated from their mothers for 3 h (maternal separation, MS), as early-life trauma is considered an important antecedent of depression. All groups were treated with either escitalopram (Esc) admixed to food (25 mg/kg.d) or vehicle for 1 month. At the week 3, forced swim tests were performed. Protein extracts from prefrontal/frontal cortex and hippocampus were separated by 2D electrophoresis. Proteins displaying statistically significant differences in expression levels were identified by mass spectrometry. Immobility time values in the forced swim test were higher in FSL rats and reduced by antidepressant treatment. Moreover, the Esc-induced reduction in immobility time was not detected in MS rats. The impact of genetic background in response to Esc was specifically investigated here. Bioinformatics analyses highlighted gene ontology terms showing tighter associations with the modulated proteins. Esc modulated protein belonging to cytoskeleton organization in FSL; carbohydrate metabolism and intracellular transport in FRL. Proteins differently modulated in the two strains after MS and Esc play a role in cytoskeleton organization, vesicle-mediated transport, apoptosis regulation and macromolecule catabolism. These findings suggest pathways involved in neuronal remodelling as molecular correlates of response to antidepressants in a model of vulnerability.

Drug prescriptions of adults with adolescent depression in a community sample

PURPOSE

The prescription drugs have, to our knowledge, not been much studied in epidemiological samples with long-term follow-up. Accordingly, our purpose was to analyze the use of prescription drugs in adults with adolescent depression.

METHODS

A population-based cohort of adolescents (n = 2465) was screened for the presence of depressive symptoms and diagnosed according to a structured interview. Totally, 362 individuals were identified as depressed and compared with 250 non-depressed controls. The prescription drugs were evaluated at the age of 29-31 years from a register kept by the National Health and Welfare Board.

RESULTS

The formerly depressed females received significantly more prescription drugs, such as antidepressants, antiepileptics, antibacterials, antimycotics, and antihistamines for systemic use as well as other drugs, compared with controls (15.6 ± 27.4 vs 8.2 ± 7.4 recipes, p < 0.001). Formerly depressed males did not differ from controls regarding prescription drugs.

CONCLUSIONS

The females but not males with adolescent depression subsequently received more prescription drugs than non-depressed peers. Depressed female adolescents received more psychotropic and non-psychotropic drugs later in life compared to the non-depressed. This might be as a result of physical illnesses, different treatment-seeking behaviors, or somatizing reactions.

Agomelatine reverses the decrease in hippocampal cell survival induced by chronic mild stress

The antidepressant agomelatine is a MT(1)/MT(2) receptor agonist and 5-HT(2C) antagonist. Its antidepressant activity is proposed to result from the synergy between these sets of receptors. Agomelatine-induced changes in the brain have been reported under basal conditions. Yet, little is known about its effects in the brain exposed to chronic stress as a risk factor for major depressive disorder. Recently, we described agomelatine-induced changes on neuronal activity and adult neurogenesis in the hippocampus of rats subjected to chronic footshock stress. In order to better characterize the actions of agomelatine in the stress-compromised brain, here we investigated its effects on hippocampal neurogenesis in the chronic mild stress (CMS) model. Adult male rats were subjected to various mild stressors for 5 weeks, and treated with agomelatine during the last 3 weeks of the stress period. The sucrose preference test was performed weekly to measure anhedonia, and the marble burying test was carried out at the end of the experiment to assess anxiety-like behavior. In our model, the CMS paradigm did not change sucrose preference; however, it increased marble burying behavior, indicating enhanced anxiety. Interestingly, this stress model differentially affected distinct stages of the neurogenesis process. Whereas CMS did not influence the rate of hippocampal cell proliferation, it significantly decreased the newborn cell survival and doublecortin expression in the dentate gyrus. Importantly, treatment with agomelatine completely normalized stress-affected cell survival and partly reversed reduced doublecortin expression. Taken together, these data show that agomelatine has beneficial effects on hippocampal neurogenesis in the CMS paradigm.

Brain microstructural abnormalities revealed by diffusion tensor images in patients with treatment-resistant depression compared with major depressive disorder before treatment

Treatment-resistant depression (TRD) is a therapeutic challenge for clinicians. Despite a growing interest in this area, an understanding of the pathophysiology of depression, particularly TRD, remains lacking. This study aims to detect the white matter abnormalities of whole brain fractional anisotropy (FA) in patients with TRD compared with major depressive disorder (MDD) before treatment by voxel-based analysis using diffusion tensor imaging. A total of 100 patients first diagnosed with untreated MDD underwent diffusion tensor imaging scans. 8 weeks after the first treatment, 54 patients showed response to the medication, whereas 46 did not. Finally, 20 patients were diagnosed with TRD after undergoing another treatment. A total of 20 patients with TRD and another 20 with MDD before treatment matched in gender, age, and education was enrolled in the research. For every subject, an FA map was generated and analyzed using SPM5. Subsequently, t-test was conducted to compare the FA values voxel to voxel between the two groups (p<0.001 [FDR corrected], t>7.57, voxel size>30). Voxel-based morphometric (VBM) analysis was performed using T1W images. Significant reductions in FA were found in the white matter located in the bilateral of the hippocampus (left hippocampus: t=7.63, voxel size=50; right hippocampus: t=7.82, voxel size=48). VBM analysis revealed no morphological abnormalities between the two groups. Investigation of brain anisotropy revealed significantly decreased FA in both sides of the hippocampus. Although preliminary, our findings suggest that microstructural abnormalities in the hippocampus indicate vulnerability to treatment resistance.

Agomelatine: efficacy at each phase of antidepressant treatment

Antidepressant pharmacotherapy forms the basis of management of major depressive disorder (MDD). In principle, the management of MDD should first elicit rapid relief of symptoms and then restore normal functioning and prevent relapse. It is recommended that treatment should continue for at least one year to minimize the risk of recurrence. Currently, most antidepressants fail to fulfill these goals, and rates of remission and long-term compliance are usually unsatisfactory. These shortcomings may be linked to tolerability and residual symptoms. Agomelatine is a novel antidepressant with an innovative mode of action characterized by agonism at the melatonergic MT(1)/MT(2) receptors and antagonism at the 5-HT(2C) receptors. As early as one week into treatment, depressive symptoms evaluated by the Clinical Global Impression Scale - Improvement (CGI-I) showed a significant improvement with agomelatine compared with venlafaxine (p < 0.0001). This rapid antidepressant efficacy was also seen at 2 weeks on the Hamilton Rating Scale for Depression (HAM-D), on which the mean total scores for agomelatine were lower than those for placebo (p < 0.05). At 6-8 weeks, evaluation on HAM-D, CGI-I and the CGI - Severity of illness (CGI-S) showed significant improvements with agomelatine versus placebo (p < 0.05). Patients treated with agomelatine also experienced greater relief of symptoms on CGI-I at 6 weeks compared with venlafaxine (p < 0.05). The antidepressant efficacy of agomelatine is maintained over the long term; almost 80% of patients remain free from relapse after 10 months of treatment. Agomelatine also significantly improves disturbed sleep and anxiety within depression, and this broad efficacy minimizes the risk of residual symptoms. The recent registration of agomelatine by the European Medicines Agency now offers the potential of fulfilling many currently unmet clinical needs throughout the time course of management of MDD.

Clomipramine treatment reversed the glial pathology in a chronic unpredictable stress-induced rat model of depression

Growing evidence indicates that glia pathology contributes to the pathophysiology and possibly the etiology of depression. The study investigates changes in behaviors and glial fibrillary associated protein (GFAP) in the rat hippocampus after chronic unpredictable stress (CUS), a rat model of depression. Furthermore, we studied the effects of clomipramine, one of tricyclic antidepressants (TCAs), known to modulate serotonin and norepinephrine uptake, on CUS-induced depressive-like behaviors and GFAP levels. Rats exposed to CUS showed behavioral deficits in physical state, open field test and forced swimming test and exhibited a significant decrease in GFAP expression in the hippocampus. Interestingly, the behavioral and GFAP expression changes induced by CUS were reversed by chronic treatment with the antidepressant clomipramine. The beneficial effects of clomipramine treatment on CUS-induced depressive-like behavior and GFAP expression provide further validation of our hypothesis that glial dysfunction contributes to the pathophysiology of depression and that glial elements may represent viable targets for new antidepressant drug development.

Standardised rating scales in psychiatry: methodological basis, their possibilities and limitations and descriptions of important rating scales

Standardized rating scales are an important tool to improve the assessment of psychopathological symptoms in terms of validity and reliability. Especially observer-rated scales are of primary importance in this respect. Self-rating scales can give a meaningful complementary view to the findings of observer-rated scales. Besides scales covering more or less the whole spectrum of psychopathological symptoms, specialised scales focussing only on symptoms of disorders like schizophrenia or depression were developed. They are widely used, specifically for pragmatic reasons.

Beyond the monoaminergic hypothesis: agomelatine, a new antidepressant with an innovative mechanism of action

There are many potentials for the development of more effective, better tolerated, and more rapidly acting antidepressants. As there is large prevalence of circadian dysfunction in various affective disorders, including depression, one of the approaches is the development of antidepressant drugs with melatonergic agonist properties. Agomelatine, with its melatonergic agonistic (at both MT(1) an MT(2) receptors) and 5-HT(2C) antagonistic properties, represents a new concept for the treatment of depression. The antidepressant action of agomelatine has been initially demonstrated in animal models of depression, such as the forced swim - the learned helplessness - and the chronic mild stress paradigms. Subsequent studies demonstrated that the antidepressant activity of agomelatine does not solely depend on its agonistic action at melatonergic receptors, but also on its antagonistic activity at 5-HT(2C) receptors. Agomelatine also exhibits anxiolytic properties that bear a striking resemblance to those of selective 5-HT(2C) receptor antagonists. In patients with major depressive disorder, agomelatine had efficacy at least comparable to that seen with available antidepressants. Interestingly, agomelatine demonstrated antidepressant efficacy not only in patients with a moderate depressive episode but also in a more severe depressed subpopulation of patients. The treatment effect increased with the severity of the disease. Agomelatine also rapidly regulates the sleep-wake cycle without causing sedation and improves daytime condition. Agomelatine has an excellent safety profile, is weight neutral, does not affect sexual functioning and does not cause discontinuation syndrome. Collectively, its efficacy, together with its excellent tolerability, makes agomelatine an especially promising antidepressant for the near future.

Desvenlafaxine succinate for major depressive disorder: a critical review of the evidence

Desvenlafaxine succinate (DVS) is the succinate salt monohydrate of O-desmethylvenlafaxine, an active metabolite of venlafaxine. DVS is a serotonin-norepinephrine reuptake inhibitor (SNRI) like venlafaxine, but exhibits a differential serotonergic and noradrenergic activity profile. A sustained-release form of DVS is approved by the US FDA for the treatment of adult major depressive disorder (MDD). DVS has shown efficacy for the treatment of MDD in clinical trials with doses ranging from 50 to 400 mg/day. The 50-100 mg/day dose range is therapeutic, with lack of additional benefit shown at higher dosages and a significantly higher risk of side effects, especially at the 400 mg/day dosing. Advantages of DVS over other sSNRIs include its simple metabolism, lower risk of drug-drug interactions and lack of need for extensive titration to achieve therapeutic efficacy. Limitations with the use of DVS include its moderate efficacy in the treatment of MDD, a safety-tolerability profile similar to that of other SNRIs and the possibility of transient discontinuation symptoms with cessation of DVS treatment. DVS is a useful addition to the options available for the treatment of MDD in light of the limited efficacy of currently available antidepressants.

A magnetic resonance imaging study of the entorhinal cortex in treatment-resistant depression

Despite a growing interest in this area, we continue to lack an understanding of the pathophysiology of depression and of treatment-resistant depression (TRD) in particular. The role of the medial temporal lobe, particularly the hippocampus, has been widely implicated in the aetiology of depression. However, related structures such as the entorhinal cortex have not been systematically examined. This research study aimed to examine possible abnormalities in the volume of the entorhinal cortex (ERC) in TRD patients. A group of 45 TRD patients and 30 healthy age- and sex-matched controls underwent magnetic resonance imaging (MRI). ERC volumes were manually traced from MRI data using ANALYZE software. An analysis of variance was conducted between subject groups and in the sexes separately while controlling for the effects of brain size via intracranial volume (ICV). Results revealed significant reductions in the volume of the left ERC of female patients. Although preliminary, our findings suggest that anatomical abnormalities in the ERC may confer vulnerability to treatment resistance. Confirmatory longitudinal studies are required to determine whether these abnormalities predate the onset of depression or are the result of a more chronic, treatment-resistant course of illness.

The effectiveness of carbamazepine in unipolar depression: a double-blind, randomized, placebo-controlled study

Our previous studies have shown the effectiveness of carbamazepine (CBZ) in the treatment of bipolar depression. This double-blind, randomized, placebo-controlled study was designed to further evaluate the efficacy of CBZ in unipolar depressed subjects who never received antidepressant and other psychotherapeutic treatment. A total of 89 patients who had at least two major depressive episodes, but never experienced mania or hypomania, were randomly assigned to treatment with immediate-release CBZ 300-800 mg/daily (n=51) or placebo (n=38) for 12 weeks. The primary efficacy was measured using the Hamilton Rating Scale for Depression (HAMD), Montgomery-Asberg Depression Rating Scale (MADRS), and Clinical Global Impression-Severity (CGI-S). The mean final CBZ dose of CBZ-treated patients was 461.6 mg/day. CBZ treatment yielded significantly greater improvements on the three efficacy measures at week 8 through endpoint compared to placebo. Patients assigned to CBZ treatment also had a significantly higher clinical response rate than placebo (74% vs. 42%, p<0.001), as defined for > or = 50% reduction in HAMD score. Based on the results of our present and previous studies, we suggest that CBZ might be considered an alternative in the management of certain conditions in major depressive disorder.

High-quality remission: potential benefits of the melatonergic approach for patients with major depressive disorder

Full remission of symptoms is the goal for the acute treatment of depression, because incomplete remission is associated with poor outcomes including higher risk of relapse and chronicity. The current definitions for remission (e.g. a score of </=7 on the Hamilton Depression Rating Scale), however, allow for the presence of residual symptoms of depression even if remission is attained. The focus now is on the quality of remission, that is, ensuring a minimum of such residual symptoms, because the consequences of low-quality remission also include impairment in psychosocial functioning. The most common residual symptoms are sleep disturbances, fatigue, and disinterest. Sleep-associated residual symptoms are particularly common, and are a major concern because most current treatments fail to adequately address sleep disturbances and may even aggravate them. Other side effects of current treatments, such as weight gain and sexual dysfunction, may also reduce the quality of remission. A novel approach to the treatment of depression with agomelatine, a melatonergic MT1 and MT2 receptor agonist and 5-HT2C receptor antagonist, may be an effective treatment that improves the quality of remission, as it combines good efficacy with positive effects on sleep, neutral effects on sexual function, and a favorable side effect profile.

Efficacy and safety of desvenlafaxine succinate in the treatment of major depressive disorder

Venlafaxine is a serotonin–norepinephrine-reuptake inhibitor (SNRI) with a well-established efficacy, safety and tolerability profile. Desvenlafaxine succinate is the succinate salt monohydrate of O-desmethylvenlafaxine, an active metabolite of venlafaxine, and, like its parent compound, is an SNRI. A sustained-release form of desvenlafaxine succinate 100 mg/day has demonstrated efficacy for the treatment of adult major depressive disorder in large multicenter trials. Desvenlafaxine succinate has a good overall safety and tolerability profile, with adverse effects comparable with those of other SNRIs. The most frequent side effects of desvenlafaxine succinate include nausea, dry mouth, constipation, dizziness, insomnia, somnolence, anorexia and sweating. The primary advantage of the sustained-release formulation over other SNRIs based on current information is related to its minimal metabolism via the cytochrome P450 (CYP450) pathway and its minimal impact on CYP450 enzyme systems. Its low potential for drug–drug interactions may have significant clinical relevance, especially in depression associated with medical comorbidities.

Intracellular signaling pathways pave roads to recovery for mood disorders

Mood disorders, including major depression and bipolar disorder, remain a major unmet medical need as current antidepressant and mood stabilizing therapies require chronic treatment for efficacy and are not effective in all patients. Multiple deficits, including cell atrophy and loss, have been observed in limbic and cortical brain regions of patients with mood disorders and in stressed animals. It is thought that antidepressant and mood stabilizing medications restore these deficits by reestablishing proper patterns of gene expression and function. In support of this hypothesis, numerous changes in gene expression and activity have been observed in limbic and cortical brain regions of mood disorder patients, and thymoleptic therapies have been shown to reciprocally regulate many of these changes. These findings have implicated four main signaling pathways in the pathophysiology and/or treatment of mood disorders, namely the cyclic-AMP, phosphoinositol, mitogen-activated protein kinase, and glycogen synthase kinase signaling cascades. Below we review this literature, and discuss potential targets for novel antidepressant and mood stabilizing drug design that are highlighted by these findings.