Antidepressant treatment in anxiety disorders

A systematic review of the association between zinc and anxiety

CONTEXT

The incidence of anxiety, which stems from both intrinsic and extrinsic factors, has been increasing worldwide. Various methods by which it can be treated or prevented have been reported thus far. One of the most popular and effective treatments is supplementation therapy. Zinc, which is an essential nutrient found in various plants, animal foods, and supplements, has been shown to be a potential nutrient in anxiety reduction by acting on γ-aminobutyric acid (GABA), glutamatergic, serotonergic, neurogenesis, and immune systems. It can also influence important receptors, such as GPR39. Thus, zinc has received considerable attention with respect to its potential role as a therapeutic or detrimental factor for anxiety; yet, the available evidence needs to be analyzed systematically to reach a convergent conclusion.

OBJECTIVE

The objective was to systematically review any potential connection between adult human anxiety and zinc intake.

DATA SOURCES AND EXTRACTION

Nine original human studies, of which 2 assessed the relationship between zinc consumption and anxiety (based on a questionnaire) and 7 assessed the relationship between serum zinc levels and anxiety, were included based on specific selection criteria. Studies that had been written in English and published in peer-reviewed publications with no restrictions on the date of publication were searched in the Google Scholar and PubMed databases. This project was also reported according to the PRISMA guidelines.

DATA ANALYSIS

As per the studies analyzed in this review, there was a noticeable relationship between serum zinc levels and anxiety, which means that patients with anxiety have lower levels of zinc in their serum, as compared with healthy individuals. Furthermore, zinc consumption was inversely associated with anxiety.

CONCLUSION

The results provide plausible evidence for the positive role of zinc in the treatment of patients afflicted with anxiety, albeit with some limitations.

Rodent tests of depression and anxiety: Construct validity and translational relevance

Behavioral testing constitutes the primary method to measure the emotional states of nonhuman animals in preclinical research. Emerging as the characteristic tool of the behaviorist school of psychology, behavioral testing of animals, particularly rodents, is employed to understand the complex cognitive and affective symptoms of neuropsychiatric disorders. Following the symptom-based diagnosis model of the DSM, rodent models and tests of depression and anxiety focus on behavioral patterns that resemble the superficial symptoms of these disorders. While these practices provided researchers with a platform to screen novel antidepressant and anxiolytic drug candidates, their construct validity-involving relevant underlying mechanisms-has been questioned. In this review, we present the laboratory procedures used to assess depressive- and anxiety-like behaviors in rats and mice. These include constructs that rely on stress-triggered responses, such as behavioral despair, and those that emerge with nonaversive training, such as cognitive bias. We describe the specific behavioral tests that are used to assess these constructs and discuss the criticisms on their theoretical background. We review specific concerns about the construct validity and translational relevance of individual behavioral tests, outline the limitations of the traditional, symptom-based interpretation, and introduce novel, ethologically relevant frameworks that emphasize simple behavioral patterns. Finally, we explore behavioral monitoring and morphological analysis methods that can be integrated into behavioral testing and discuss how they can enhance the construct validity of these tests.

Anxiolytic Effect of Carvedilol in Chronic Unpredictable Stress Model

Anxiety disorders are the most prevalent psychiatric disorders being also a comorbid state of other diseases. We aimed to evaluate the anxiolytic-like effects of carvedilol (CVD), a drug used to treat high blood pressure and heart failure with potent antioxidant effects, in animals exposed to chronic unpredictable stress (CUS). To do this, female Swiss mice were exposed to different stressors for 21 days. Between days 15 and 21, the animals received oral CVD (5 or 10 mg/kg) or the antidepressant desvenlafaxine (DVS 10 mg/kg). On the 22^nd day, behavioral tests were conducted to evaluate locomotor activity (open field) and anxiety-like alterations (elevated plus-maze—EPM and hole board—HB tests). After behavioral determinations, the animals were euthanized, and the adrenal gland, blood and brain areas, prefrontal cortex (PFC), and hippocampus were removed for biochemical analysis. CUS reduced the crossings while increased rearing and grooming, an effect reversed by both doses of CVD and DVS. CUS decreased the number of entries and permanence time in the open arms of the EPM, while all treatments reversed this effect. CUS reduced the number of head dips in the HB, an effect reversed by CVD. The CUS reduced weight gain, while only CVD5 reversed this effect. A reduction in the cortical layer size of the adrenal gland was observed in stressed animals, which CVD reversed. Increased myeloperoxidase activity (MPO) and interferon-γ (IFN-γ), as well as reduction of interleukin-4 (IL-4) induced by CUS, were reversed by CVD. DVS and CVD increased IL-6 in both brain areas. In the hippocampus, DVS caused an increase in IFN-γ. Our data show that CVD presents an anxiolytic effect partially associated with immune-inflammatory mechanism regulation.

Elucidating the Interactions of Fluoxetine with Human Transferrin Employing Spectroscopic, Calorimetric, and In Silico Approaches: Implications of a Potent Alzheimer's Drug

Neurodegenerative complexities, such as dementia, Alzheimer's disease (AD), and so forth, have been a crucial health concern for ages. Transferrin (Tf) is a chief target to explore in AD management. Fluoxetine (FXT) presents itself as a potent anti-AD drug-like compound and has been explored against several diseases based on the drug repurposing readings. The present study delineates the binding of FXT to Tf employing structure-based docking, molecular dynamics (MD) simulations, and principal component analysis (PCA). Docking results showed the binding of FXT with Tf with an appreciable binding affinity, making various close interactions. MD simulation of FXT with Tf for 100 ns suggested their stable binding without any significant structural alteration. Furthermore, fluorescence-based binding revealed a significant interaction between FXT and Tf. FXT binds to Tf with a binding constant of 5.5 × 10⁵ M^-1. Isothermal titration calorimetry (ITC) advocated the binding of FXT to Tf as spontaneous in nature, affirming earlier observations. This work indicated plausible interactions between FXT and Tf, which are worth considering for further studies in the clinical management of neurological disorders, including AD.

Depresssion, anxiety and other cognitive consequences of social isolation: Drug and non-drug treatments

OBJECTIVE

During the COVID-19 pandemic, quarantine and staying at home is advised. The social relationship between people has become deficient, and human social isolation (SI) has become the consequence of this situation. It was shown that SI has made changes in hippocampal neuroplasticity, which will lead to poor cognitive function and behavioural abnormalities. There is a connection between SI, learning, and memory impairments. In addition, anxiety-like behaviour and increased aggressive mood in long-term isolation have been revealed during the COVID-19 outbreak.

METHODS

Term searches was done in Google Scholar, Scopus, ScienceDirect, Web of Science and PubMed databases as well as hand searching in key resource journals from 1979 to 2020.

RESULTS

Studies have shown that some drug administrations may positively affect or even prevent social isolation consequences in animal models. These drug treatments have included opioid drugs, anti-depressants, Antioxidants, and herbal medications. In addition to drug interventions, there are non-drug treatments that include an enriched environment, regular exercise, and music.

CONCLUSION

This manuscript aims to review improved cognitive impairments induced by SI during COVID-19.

Prescribing patterns of psychotropic medications in psychiatric disorders: a descriptive study from Palestine

Background The practice patterns of psychiatrists have changed over the last two decades. Objectives This study describes the pattern of prescribing psychotropic drugs in treating common psychiatric disorders, and investigates the rate of polypharmacy and potential drug-drug interactions. Setting Psychiatry governmental outpatient clinic in the north of West Bank, Palestine. Methods Cross-sectional study that included all prescriptions which were issued over the period October 2018 to January 2019, for patients diagnosed with schizophrenia, depression, anxiety, bipolar disorder and schizoaffective disorders, and checked for the presence and the grade of potential drug-drug interactions using "Medscape drug interactions checker". Main outcome measure Prescribing patterns of psychotropic drugs. Results A total of 1045 prescriptions were examined. The mean age of the patients was 47.3 years (SD = 13.6), two-thirds of the patients (64.5%) were males. Fifty-two percent of the patients were diagnosed with schizophrenia while 15.2% were diagnosed with depression. The later third was diagnosed with bipolar disorder, schizoaffective and anxiety disorders (15.8%, 11.1% and 5.1% respectively). The most commonly prescribed drugs were typical antipsychotics for schizophrenia, bipolar and schizoaffective disorders, selective serotonin reuptake inhibitors for depression and tricyclic anti-depressants for anxiety. Polypharmacy was found in 877 prescriptions (84%), and drug-drug interactions (DDIs) were identified in 823 (94%) prescriptions. The DDIs were classified as minor (4, 0.5%), significant (418, 50.8%) and serious (401, 48.7%). Conclusions Our results suggest that the pharmacotherapy of psychiatric disorders in Palestine may not be in accordance to international guidelines and the incidence of polypharmacy and DDIs is high.

Serotonin pathway polymorphisms and the treatment of major depressive disorder and anxiety disorders

While antidepressants are widely used to treat major depressive disorder and anxiety disorders, only half of the patients will respond to antidepressant treatment and only a third of patients will experience a remission of symptoms. Identification of genetic biomarkers that predict antidepressant treatment response could thus greatly improve current clinical practice by providing guidance on which drug to use for which patient. Most antidepressant drugs for the treatment of depression and anxiety disorders have effects on the serotonergic neurotransmitter system; thus, genetic polymorphisms in the genes involved in this pathway represent logical candidates for investigation. This article reviews recent findings on the pharmacogenetics of antidepressant drugs with a focus on serotonergic pathway polymorphisms and discusses future clinical applications.

Facilitation of serotonin signaling by SSRIs is attenuated by social isolation

Hypofunction of the serotonergic system is often associated with major depression and obsessive compulsive disorder (OCD). Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed to treat these disorders, and require 3-6 weeks of chronic treatment before improvements in the symptoms are observed. SSRIs inhibit serotonin's transporter, and in doing so, increase extracellular serotonin concentrations. Thus, efficacy of SSRIs likely depends upon the brain's adaptive response to sustained increases in serotonin levels. Individual responsiveness to SSRI treatment may depend on a variety of factors that influence these changes, including ongoing stress. Social isolation is a passive, naturalistic form of chronic mild stress that can model depression in rodents. In this study, we examined how 20-day treatment with the SSRI citalopram (CIT) alters marble-burying (MB), open field behavior, and serotonin signaling in single- vs pair-housed animals. We used in vivo voltammetry to measure electrically evoked serotonin, comparing release rate, net overflow, and clearance. Pair-housed mice were significantly more responsive to CIT treatment, exhibiting reduced MB and facilitation of serotonin release that positively correlated with the frequency of electrical stimulation. These effects of CIT treatment were attenuated in single-housed mice. Notably, although CIT treatment enhanced serotonin release in pair-housed mice, it did not significantly alter uptake rate. In summary, we report that chronic SSRI treatment facilitates serotonin release in a frequency-dependent manner, and this effect is blocked by social isolation. These findings suggest that the efficacy of SSRIs in treating depression and OCD may depend on ongoing stressors during treatment.

Antidepressant and anxiolytic potential of the multimodal antidepressant vortioxetine (Lu AA21004) assessed by behavioural and neurogenesis outcomes in mice

Vortioxetine (Lu AA21004) is an investigational novel antidepressant with multimodal activity that functions as a 5-HT3, 5-HT7 and 5-HT(1D) receptor antagonist, 5-HT(1B) receptor partial agonist, 5-HT(1A) receptor agonist and inhibitor of the 5-HT transporter in vitro. Here we explore its anxiolytic and antidepressant potential in adult mice. Vortioxetine was assessed in BalB/cJ@RJ mice using the open-field and forced-swim tests (acute: p.o. 1 h, repeated: daily p.o. 21 days), and in 129S6/SvEvTac mice using the novelty suppressed feeding paradigm (acute: p.o. 1 h, sustained: daily p.o. 14 or 21 days). Fluoxetine and diazepam were controls. Acute and repeated dosing of vortioxetine produced more pronounced anxiolytic- and antidepressant-like activities than fluoxetine. Vortioxetine significantly increased cell proliferation and cell survival and stimulated maturation of immature granule cells in the subgranular zone of the dentate gyrus of the hippocampus after 21 days of treatment. After 14 days, a high dose of vortioxetine increased dendritic length and the number of dendrite intersections, suggesting that vortioxetine accelerates the maturation of immature neurons. Vortioxetine displays an antidepressant and anxiolytic profile following repeated administration associated with increased neurogenesis at several stages. Vortioxetine effects were observed at low levels of 5-HT transporter occupancy, suggesting an alternative mechanism of action to 5-HT reuptake inhibition.

Outlining new frontiers for the comprehension of obsessive-compulsive disorder: a review of its relationship with fear and anxiety

Anxiety is an important component of the psychopathology of the obsessive-compulsive disorder (OCD). So far, most interventions that have proven to be effective for treating OCD are similar to those developed for other anxiety disorders. However, neurobiological studies of OCD came to conclusions that are not always compatible with those previously associated with other anxiety disorders.

OBJECTIVES

The aim of this study is to review the degree of overlap between OCD and other anxiety disorders phenomenology and pathophysiology to support the rationale that guides research in this field.

RESULTS

Clues about the neurocircuits involved in the manifestation of anxiety disorders have been obtained through the study of animal anxiety models, and structural and functional neuroimaging in humans. These investigations suggest that in OCD, in addition to dysfunction in cortico-striatal pathways, the functioning of an alternative neurocircuitry, which involves amygdalo-cortical interactions and participates in fear conditioning and extinction processes, may be impaired.

CONCLUSION

It is likely that anxiety is a relevant dimension of OCD that impacts on other features of this disorder. Therefore, future studies may benefit from the investigation of the expression of fear and anxiety by OCD patients according to their type of obsessions and compulsions, age of OCD onset, comorbidities, and patterns of treatment response.

Neuropsychological predictors of response to randomized treatment in obsessive-compulsive disorder

OBJECTIVE

To identify neuropsychological predictors of treatment response to cognitive-behavioral therapy (CBT) and fluoxetine in treatment-naïve adults with obsessive-compulsive disorder (OCD).

METHOD

Thirty-eight adult outpatients with OCD underwent neuropsychological assessment, including tasks of intellectual function, executive functioning and visual and verbal memory, before randomization to a 12-week clinical trial of either CBT or fluoxetine. Neuropsychological measures were used to identify predictors of treatment response in OCD.

RESULTS

Neuropsychological measures that predicted a better treatment response to either CBT or fluoxetine were higher verbal IQ (Wechsler Abbreviated Scale of Intelligence) (p=0.008); higher verbal memory on the California Verbal Learning Test (p=0.710); shorter time to complete part D (Dots) (p<0.001), longer time to complete part W (Words) (p=0.025) and less errors on part C (Colors) (p<0.001) in the Victoria Stroop Test (VST). Fewer perseverations on the California Verbal Learning Test, a measure of mental flexibility, predicted better response to CBT, but worse response to fluoxetine (p=0.002).

CONCLUSION

In general, OCD patients with better cognitive and executive abilities at baseline were more prone to respond to either CBT or fluoxetine. Our finding that neuropsychological measures of mental flexibility predicted response to treatment in opposite directions for CBT and fluoxetine suggests that OCD patients with different neuropsychological profiles may respond preferentially to one type of treatment versus the other. Further studies with larger samples of OCD patients are necessary to investigate the heuristic value of such findings in a clinical context.

The genetics of selective serotonin reuptake inhibitors

Selective serotonin reuptake inhibitors (SSRIs) are among the most widely prescribed drugs in psychiatry. Based on the fact that SSRIs increase extracellular monoamine levels in the brain, the monoamine hypothesis of depression was introduced, postulating that depression is associated with too low serotonin, dopamine and noradrenaline levels. However, several lines of evidence indicate that this hypothesis is too simplistic and that depression and the efficacy of SSRIs are dependent on neuroplastic changes mediated by changes in gene expression. Because a coherent view on global gene expression is lacking, we aim to provide an overview of the effects of SSRI treatment on the final targets of 5-HT receptor signal transduction pathways, namely the transcriptional regulation of genes. We address gene polymorphisms in humans that affect SSRI efficacy, as well as in vitro studies employing human-derived cells. We also discuss the molecular targets affected by SSRIs in animal models, both in vivo and in vitro. We conclude that serotonin transporter gene variation in humans affects the efficacy and side-effects of SSRIs, whereas SSRIs generally do not affect serotonin transporter gene expression in animals. Instead, SSRIs alter mRNA levels of genes encoding serotonin receptors, components of non-serotonergic neurotransmitter systems, neurotrophic factors, hypothalamic hormones and inflammatory factors. So far little is known about the epigenetic and age-dependent molecular effects of SSRIs, which might give more insights in the working mechanism(s) of SSRIs.

Alterations in prefrontal cortical serotonin and antidepressant-like behavior in a novel C3H/HeJxDBA/2J recombinant inbred mouse strain

In the present study, two genetically related inbred mouse strains selectively bred for high and low fear-sensitized acoustic startle reflex (FSS) were assessed in the forced swim test model of anti-depressant action and central monoamine concentrations in several brain regions were investigated. These mice were generated through backcrossing C3H/HeJ mice on DBA/2J mice, followed by inbreeding for several generations. The high-FSS and low-FSS strains are known to differ in their acquisition and extinction of fear following auditory fear conditioning. Significantly increased concentrations of 5-HT and its metabolite 5-HIAA were observed in the medial prefrontal cortex (mPFC) but not in the hypothalamus, striatum, hippocampus, amygdala, or midbrain of high-FSS mice compared to low-FSS mice. In addition the concentration of DOPAC, the major metabolite of dopamine was also significantly increased in the mPFC. Furthermore, the high-FSS mice displayed significantly higher levels of immobility in the forced swim test but not the tail suspension test in comparison to the low-FSS group. The mPFC is not only important in the regulation of fear extinction, but also a key region of interest in the study of depression and maintenance of depressive-like behaviors. These data implicate serotonergic modulation in the mPFC in the maintenance of antidepressant-like behavior in a highly fearful mouse strain.

Symptom-specific attentional bias to threatening stimuli in obsessive-compulsive disorder

OBJECTIVE

There is mixed evidence as to whether patients with obsessive-compulsive disorder (OCD) have excessive attentional engagement and emotional response to OCD-related stimuli in the environment. Here we investigate the occurrence of an attentional bias toward specific OCD-related stimuli and its relationship with obsessive-compulsive symptom dimensions.

METHODS

Forty-eight patients with OCD participated in an attentional bias task containing OCD- and non-OCD-related stimuli and had their performance compared with that of 24 age-, sex-, and education-matched healthy control subjects. Severity of obsessive-compulsive and comorbid depressive symptoms was assessed using the Obsessive-Compulsive Inventory-Revised and the Beck Depression Inventory, respectively.

RESULTS

Although there were significant and almost significant group effects on the reaction time (RT) toward OCD- and non-OCD-related figures, respectively, no difference between patients with OCD and controls was noted with regard to RT toward OCD-related figures minus RT toward non-OCD-related figures. Nevertheless, within the OCD group, partial correlational analysis controlled for age and severity of depression unveiled positive correlations between (1) obsessional symptoms and RT toward checking-related pictures and (2) ordering symptoms and RT toward ordering-related pictures.

CONCLUSIONS

The positive correlations between RT to content-specific stimuli and the severity of corresponding obsessive-compulsive symptoms suggest that patients with OCD experience difficulty in disengaging attention from personally salient stimuli.

Anxious ultimatums: how anxiety disorders affect socioeconomic behaviour

Although the role of emotion in socioeconomic decision making is increasingly recognised, the impact of specific emotional disorders, such as anxiety disorders, on these decisions has been surprisingly neglected. Twenty anxious patients and twenty matched controls completed a commonly used socioeconomic task (the Ultimatum Game), in which they had to accept or reject monetary offers from other players. Anxious patients accepted significantly more unfair offers than controls. We discuss the implications of these findings in light of recent models of anxiety, in particular the importance of interpersonal factors and assertiveness in an integrated model of decision making. Finally, we were able to show that pharmacological serotonin used to treat anxious symptomatology tended to normalise decision making, further confirming and extending the role of serotonin in co-operation, prosocial behaviour, and social decision making. These results show, for the first time, a different pattern of socioeconomic behaviour in anxiety disordered patients, in addition to the known memory, attentional and emotional biases that are part of this pathological condition.

Treating anxiety by discontinuing antidepressants: a case series

When a patient has symptoms of anxiety, while taking an antidepressant for depression, is it possible that the antidepressant is part of the problem? Can antidepressants cause anxiety? If this were so, even if relatively rare, it would have widespread implications because of the broad use of antidepressants. However, antidepressants are widely used as a treatment for anxiety. Therefore, unless suggestive evidence were to emerge to implicate them as a potential exacerbating factor, broad use of antidepressants would likely continue for patients whose depression has improved but whose anxiety has not responded, or worsened. In that context we present 12 patients whose anxiety diminished substantially when antidepressants were tapered off, as reflected in Clinical Global Improvement Scale scores assigned by their respective clinicians. Mean duration of antidepressant taper was 17 weeks (range 0-48), as suggested by limited prior evidence supporting very slow taper rates for this purpose. Alternative treatments for depression were often used for these patients as antidepressants were tapered, particularly lithium and lamotrigine, but none of the alternatives used are generally regarded as having anti-anxiety effects. Patients with bipolar disorder diagnoses, including schizoaffective disorder, were specifically excluded. In many of these cases, other medications that might have anti-anxiety effects (including buspirone, quetiapine, olanzapine, gabapentin, and diphenhydramine) were also tapered off. Results suggest that antidepressants may actually cause anxiety in some patients with unipolar depression. Alternatively, lamotrigine or lithium may have more anti-anxiety effects than generally recognized; or these patients may have had subtle bipolar disorder despite the absence of symptoms meeting formal criteria, supporting the "bipolar spectrum" perspective on mood disorder diagnosis. This study is limited by the outcome measure used, which assesses anxiety only indirectly in the context of global improvement. However, in view of the broad implications of the findings, these preliminary observations warrant further consideration. Some patients with anxiety may be treatable not by adding medications, but rather by tapering off existing ones.

Pharmacogenetics of antidepressant drugs: current clinical practice and future directions

While antidepressants are widely used to treat mood and anxiety disorders, only half of the patients will respond to antidepressant treatment and only one-third of patients experience a full remission of symptoms. The identification of genetic biomarkers that predict antidepressant-treatment response can improve current clinical practice. This is an emerging field known as pharmacogenetics, which comprises of genetic studies on both the pharmacokinetics and pharmacodynamics of treatment response. Recent studies on antidepressant-treatment response have focused on both aspects of pharmacogenetics research, identifying new candidate genes that may predict better treatment response for patients. This paper reviews recent findings on the pharmacogenetics of antidepressant drugs and future clinical applications. Ultimately, these studies should lead to the use of genetic testing to guide the use of antidepressants in clinical practice.

Supplemental dietary choline during development exerts antidepressant-like effects in adult female rats

Perinatal choline supplementation in rats is neuroprotective against insults such as fetal alcohol exposure, seizures, and advanced age. In the present study we explored whether dietary choline supplementation may also confer protection from psychological challenges, like stress, and act as a natural buffer against stress-linked psychological disorders, like depression. We previously found that choline supplementation increased adult hippocampal neurogenesis, a function compromised by stress, lowered in depression, and boosted by antidepressants; and increased levels of growth factors linked to depression, like brain-derived neurotrophic factor. Together, these were compelling reasons to study the role of choline in depressed mood. To do this, we treated rats with a choline supplemented diet (5 mg/kg choline chloride in AIN76A) prenatally on embryonic days 10-22, on postnatal days (PD) 25-50, or as adults from PD75 onward. Outside of these treatment periods rats were fed a standard diet (1.1 mg/kg choline chloride in AIN76A); control rats consumed only this diet throughout the study. Starting on PD100 rats' anxiety-like responses to an open field, learning in a water maze, and reactivity to forced swimming were assessed. Rats given choline supplementation during pre- or post-natal development, but not adult-treated rats, were less anxious in the open field and less immobile in the forced swim test than control rats. These effects were not mediated by a learning deficit as all groups performed comparably and well in the water maze. Thus, we offer compelling support for the hypothesis that supplemental dietary choline, at least when given during development, may inoculate an individual against stress and major psychological disorders, like depression.