Pharmacotherapy in Generalized Anxiety Disorder: Novel Experimental Medicine Models and Emerging Drug Targets

Placebo Effects Are Small on Average in the 7.5% CO2 Inhalational Model of Generalized Anxiety

BACKGROUND

Anxiety disorders are highly prevalent and socio-economically costly. Novel pharmacological treatments for these disorders are needed because many patients do not respond to current agents or experience unwanted side effects. However, a barrier to treatment development is the variable and large placebo response rate seen in trials of novel anxiolytics. Despite this, the mechanisms that drive placebo responses in anxiety disorders have been little investigated, possibly due to low availability of convenient experimental paradigms. We aimed to develop and test a novel protocol for inducing placebo anxiolysis in the 7.5% CO2 inhalational model of generalized anxiety in healthy volunteers.

METHODS

Following a baseline 20-minute CO2 challenge, 32 healthy volunteers were administered a placebo intranasal spray labelled as either the anxiolytic "lorazepam" or "saline." Following this, participants surreptitiously underwent a 20-minute inhalation of normal air. Post-conditioning, a second dose of the placebo was administered, after which participants completed another CO2 challenge.

RESULTS

Participants administered sham "lorazepam" reported significant positive expectations of reduced anxiety (P = .001), but there was no group-level placebo effect on anxiety following CO2 challenge post-conditioning (Ps > .350). Surprisingly, we found many participants exhibited unexpected worsening of anxiety, despite positive expectations.

CONCLUSIONS

Contrary to our hypothesis, our novel paradigm did not induce a placebo response, on average. It is possible that effects of 7.5% CO2 inhalation on prefrontal cortex function or behavior in line with a Bayesian predictive coding framework attenuated the effect of expectations on subsequent placebo response. Future studies are needed to explore these possibilities.

Pharmacological Treatment of Generalised Anxiety Disorder: Current Practice and Future Directions

INTRODUCTION

Generalized Anxiety Disorder (GAD) is a common psychiatric condition, characterized by the presence of general apprehensiveness and excessive worry. Current management consists of a range of pharmacological and psychological treatments. However, many patients do not respond to first-line pharmacological treatments and novel anxiolytic drugs are being developed.

AREAS COVERED

In this review, the authors first discuss the diagnostic criteria and epidemiology of GAD. The effective pharmacological treatments for GAD and their tolerability are addressed. Current consensus guidelines for treatment of GAD are discussed, and maintenance treatment, the management of treatment resistance, and specific management of older adults and children/adolescents are considered. Finally, novel anxiolytics under development are discussed, with a focus on those which have entered clinical trials.

EXPERT OPINION

A range of effective treatments for GAD are available, particularly duloxetine, escitalopram, pregabalin, quetiapine, and venlafaxine. There is a limited evidence base to support the further pharmacological management of patients with GAD who have not responded to initial treatment. Although many novel anxiolytics have progressed to clinical trials, translation from animal models has been mostly unsuccessful. However, the potential of several compounds including certain psychedelics, ketamine, oxytocin, and agents modulating the orexin, endocannabinoid, and immune systems merits further study.

A novel procedure to investigate social anxiety using videoconferencing software: A proof-of-concept study

Social anxiety disorder (SAD) is very common and can be significantly disabling. New treatments are needed as the remission rate for SAD is the lowest of all the anxiety disorders. Experimental medicine models, in which features resembling a clinical disorder are experimentally induced, are a cost-effective and timely approach to explore potential novel treatments for psychiatric disorders. Following the emergence of SARS-CoV-2, there is a need to develop experimental medicine models that can be carried out remotely. We developed a novel procedure to investigate SAD (the InterneT-based Stress test for Social Anxiety Disorder; ITSSAD) that can be carried out entirely online by a single investigator, potentially reducing costs and maximising internal reliability. The procedure involves an anticipatory period followed by a naturalistic social interaction task. In a sample of 20 non-treatment-seeking volunteers with symptoms of SAD, the ITSSAD induced significant subjective anxiety and reduced positive affect. Further, increased social anxiety symptoms at baseline predicted increased anxiety during the social interaction task. This protocol needs further validation with physiological measures. The ITSSAD is a new tool for researchers to investigate mechanisms underlying social anxiety disorder.

Effect of Marxist ideological and political education on students' anxiety in colleges and universities

With the rapid development of China's economy, politics and culture, the frequency of college students' anxiety has generally increased. Ideological and political educators in colleges should help college students to relieve anxiety and pressure in a timely manner, and constantly put forward effective and targeted methods. This paper analyzed the reasons for the anxiety of college students from three aspects: the way of dealing with the interpersonal relationship of college students, the degree of emphasis on college students' academic performance, and the way of college students' self-decompression. This paper proposed ways to strengthen the ability of thinking, carry out setback education, and improve the psychological quality of college students to realize the Marxist ideological and political education in colleges. This paper mainly used questionnaires and in-depth interviews to analyze the influence of mental health education courses on college students' anxiety management ability. Among them, after the end of the mental health education course, a questionnaire was distributed to the selected research subjects to understand their stress management ability status after the course. Through the analysis and comparison of the results of the two questionnaires before and after, as well as the comparison of the conventional teaching methods of college students' mental health education different from the teaching methods of group psychological counseling, it is necessary to understand the way college students' deal with anxiety. The study found that 19.23% of the students had great anxiety about interpersonal communication problems, and 9.62% of the students reported that they had no major anxiety problems. Therefore, Marxist ideological and political education in colleges has become an important means for college students to vent their emotions, relieve psychological pressure and avoid adverse consequences.

Effects of group mindfulness-based cognitive therapy and group cognitive behavioural therapy on symptomatic generalized anxiety disorder: a randomized controlled noninferiority trial

BACKGROUND

Mindfulness-based cognitive therapy (MBCT) is a promising alternative treatment for generalized anxiety disorder (GAD). The objective of this study was to examine whether the efficacy of group MBCT adapted for treating GAD (MBCT-A) was noninferior to group cognitive behavioural therapy (CBT) designed to treat GAD (CBT-A), which was considered one of first-line treatments for GAD patients. We also explored the efficacy of MBCT-A in symptomatic GAD patients compared with CBT-A for a variety of outcomes of anxiety symptoms, as well as depressive symptoms, overall illness severity, quality of life and mindfulness.

METHODS

This was a randomized, controlled, noninferiority trial with two arms involving symptomatic GAD patients. Adult patients with GAD (n = 138) were randomized to MBCT-A or CBT-A in addition to treatment as usual (TAU). The primary outcome was the anxiety response rate assessed at 8 weeks after treatment as measured using the Hamilton Anxiety Scale (HAMA). Secondary outcomes included anxiety remission rates, scores on the HAMA, the state-trait anxiety inventory (STAI), the Hamilton Depression Scale (HAMD), the Severity Subscale of the Clinical Global Impression Scale (CGI-S), and the 12-item Short-Form Health Survey (SF-12), as well as mindfulness, which was measured by the Five Facet Mindfulness Questionnaire (FFMQ). Assessments were performed at baseline, 8 weeks after treatment, and 3 months after treatment. Both intention-to-treat (ITT) and per-protocol (PP) analyses were performed for primary analyses. The χ2 test and separate two-way mixed ANOVAs were used for the secondary analyses.

RESULTS

ITT and PP analyses showed noninferiority of MBCT-A compared with CBT-A for response rate [ITT rate difference = 7.25% (95% CI: -8.16, 22.65); PP rate difference = 5.85% (95% CI: - 7.83, 19.53)]. The anxiety remission rate, overall illness severity and mindfulness were significantly different between the two groups at 8 weeks. There were no significant differences between the two groups at the 3-month follow-up. No severe adverse events were identified.

CONCLUSIONS

Our data indicate that MBCT-A was noninferior to CBT-A in reducing anxiety symptoms in GAD patients. Both interventions appeared to be effective for long-term benefits.

TRIAL REGISTRATION

Registered at chictr.org.cn (registration number: ChiCTR1800019150 , registration date: 27/10/2018).

The interplay of hypoxic and mental stress: Implications for anxiety and depressive disorders

Adequate oxygen supply is essential for the human brain to meet its high energy demands. Therefore, elaborate molecular and systemic mechanism are in place to enable adaptation to low oxygen availability. Anxiety and depressive disorders are characterized by alterations in brain oxygen metabolism and of its components, such as mitochondria or hypoxia inducible factor (HIF)-pathways. Conversely, sensitivity and tolerance to hypoxia may depend on parameters of mental stress and the severity of anxiety and depressive disorders. Here we discuss relevant mechanisms of adaptations to hypoxia, as well as their involvement in mental stress and the etiopathogenesis of anxiety and depressive disorders. We suggest that mechanisms of adaptations to hypoxia (including metabolic responses, inflammation, and the activation of chemosensitive brain regions) modulate and are modulated by stress-related pathways and associated psychiatric diseases. While severe chronic hypoxia or dysfunctional hypoxia adaptations can contribute to the pathogenesis of anxiety and depressive disorders, harnessing controlled responses to hypoxia to increase cellular and psychological resilience emerges as a novel treatment strategy for these diseases.

Clinical management of withdrawal from benzodiazepine anxiolytic and hypnotic medications

Benzodiazepines continue to be prescribed widely in the management of patients with insomnia or anxiety disorders, despite the availability and acceptability of alternative pharmacological and psychological treatments. Many patients will experience adverse effects during treatment and considerable distress when the dosage is reduced and stopped. Management of benzodiazepine withdrawal includes measures to prevent the development of dependence, careful attention to underlying medical conditions, medication consolidation and gradual dosage reduction, accompanying psychological interventions, occasional prescription of concomitant medication, and relapse prevention with on-going support to address psychosocial stressors. There are needs for easier patient access to services with refined expertise and for further research to optimise strategies for preventing dependence and facilitating withdrawal.

Cognitive Behavior Therapy Targeting Intolerance of Uncertainty Versus Selective Serotonin Reuptake Inhibitor for Generalized Anxiety Disorder: A Randomized Clinical Trial

Given the high prevalence and adverse outcomes associated with generalized anxiety disorder (GAD), development and expansion of effective treatment modalities are important. The present study compared the effectiveness of cognitive behavior therapy targeting intolerance of uncertainty (CBT-IU) and selective serotonin reuptake inhibitors (SSRIs) for treating GAD. A total of 30 Iranian patients with GAD (Mage = 25.16 ± 6.73) were randomised to receive either CBT-IU (n = 15) or SSRI (n = 15). Measures included the Structured Clinical Interview for DSM-5 (SCID-5), Penn State Worry Questionnaire (PSWQ), Why Worry-II (WW-II), Intolerance of Uncertainty Scale (IUS), and Negative Problem Orientation Questionnaire (NPOQ). Repeated measures analysis of variance tested differential treatment outcomes. The results of intention-to-treat (ITT) analysis indicated that although both CBT-IU and SSRI were effective treatments for GAD, CBT-IU produced significantly better results than SSRI at post-treatment. This clinical trial provides preliminary cross-cultural support for the treatment of GAD using CBT-IU, with findings suggesting that this non-medication intervention reduces GAD symptoms.

What Animal Models Can Tell Us About Long-Term Psychiatric Symptoms in Sepsis Survivors: a Systematic Review

Lower sepsis mortality rates imply that more patients are discharged from the hospital, but sepsis survivors often experience sequelae, such as functional disability, cognitive impairment, and psychiatric morbidity. Nevertheless, the mechanisms underlying these long-term disabilities are not fully understood. Considering the extensive use of animal models in the study of the pathogenesis of neuropsychiatric disorders, it seems adopting this approach to improve our knowledge of postseptic psychiatric symptoms is a logical approach. With the purpose of gathering and summarizing the main findings of studies using animal models of sepsis-induced psychiatric symptoms, we performed a systematic review of the literature on this topic. Thus, 140 references were reviewed, and most of the published studies suggested a time-dependent recovery from behavior alterations, despite the fact that some molecular alterations persist in the brain. This review reveals that animal models can be used to understand the mechanisms that underlie anxiety and depression in animals recovering from sepsis.

A longitudinal analysis of cytokines in anorexia nervosa

OBJECTIVE

Inflammation has been proposed to have a pathophysiological role in anorexia nervosa (AN) and to contribute to the maintenance of the disorder. Longitudinal cytokine research in AN has focused on only a few pro-inflammatory cytokines. We assessed a broad range of cytokines over time in people undergoing specialised treatment for AN.

METHOD

We measured serum concentrations of 27 cytokines in people with AN (n = 23). Body mass index (BMI), eating disorder (ED) symptoms and general psychopathology were assessed and blood samples were collected within four weeks of the commencement of specialised ED treatment (baseline) and at 12- and 24-week follow-ups.

RESULTS

Both BMI and ED symptoms improved over the assessment period. Linear mixed models showed that log IL-6 decreased between baseline and week 12 assessments. By week 12, log IL-6 values were comparable to levels in healthy individuals. Log IL-7 increased from week 12 to week 24.

DISCUSSION

Initially elevated IL-6 serum concentrations appear to 'normalize' during the first 3-months of specialised treatment for AN and this co-occurs with improvements in ED symptoms. Therefore, IL-6 has the potential to be a state biomarker for AN.

Current and Novel Psychopharmacological Drugs for Anxiety Disorders

Anxiety disorders, including panic disorder/agoraphobia (PDA), generalized anxiety disorder (GAD), social anxiety disorder (SAD), and others, are the most prevalent mental disorders. In this paper, recommendations are given for the psychopharmacological treatment of these disorders which are based on comprehensive treatment guidelines, meta-analyses, and systematic reviews of available randomized controlled studies. Anxiety disorders can effectively be treated with psychotherapy, pharmacotherapy, or a combination of both. First-line drugs are the selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). Benzodiazepines are not recommended for routine use due to their possible addiction potential. Other treatment options include the calcium modulator pregabalin, tricyclic antidepressants, buspirone, moclobemide, and others. Drug treatment can be combined with psychological treatments. Novel treatment strategies include medications that act on GABA, glutamate, and other neurotransmitter systems. After remission, medications should be continued for 6 to 12 months.

The efficacy of group cognitive-behavioural therapy plus duloxetine for generalised anxiety disorder versus duloxetine alone

OBJECTIVE

To explore whether and how group cognitive-behavioural therapy (GCBT) plus medication differs from medication alone for the treatment of generalised anxiety disorder (GAD).

METHODS

Hundred and seventy patients were randomly assigned to the GCBT plus duloxetine (n=89) or duloxetine group (n=81). The primary outcomes were Hamilton Anxiety Scale (HAMA) response and remission rates. The explorative secondary measures included score reductions from baseline in the HAMA total, psychic, and somatic anxiety subscales (HAMA-PA, HAMA-SA), the Hamilton Depression Scale, the Severity Subscale of Clinical Global Impression Scale, Global Assessment of Functioning, and the 12-item Short-Form Health Survey. Assessments were conducted at baseline, 4-week, 8-week, and 3-month follow-up.

RESULTS

At 4 weeks, HAMA response (GCBT group 57.0% vs. control group 24.4%, p=0.000, Cohen's d=0.90) and remission rates (GCBT group 21.5% vs. control group 6.2%, p=0.004; d=0.51), and most secondary outcomes (all p<0.05, d=0.36-0.77) showed that the combined therapy was superior. At 8 weeks, all the primary and secondary significant differences found at 4 weeks were maintained with smaller effect sizes (p<0.05, d=0.32-0.48). At 3-month follow-up, the combined therapy was only significantly superior in the HAMA total (p<0.045, d=0.43) and HAMA-PA score reductions (p<0.001, d=0.77). Logistic regression showed superiority of the combined therapy for HAMA response rates [odds ratio (OR)=2.12, 95% confidence interval (CI) 1.02-4.42, p=0.04] and remission rates (OR=2.80, 95% CI 1.27-6.16, p=0.01).

CONCLUSIONS

Compared with duloxetine alone, GCBT plus duloxetine showed significant treatment response for GAD over a shorter period of time, particularly for psychic anxiety symptoms, which may suggest that GCBT was effective in changing cognitive style.

Effects of N-acetylcysteine amide on anxiety and stress behavior in zebrafish

Anxiety disorders are highly prevalent and a leading cause of disability worldwide. Their etiology is related to stress, an adaptive response of the organism to restore homeostasis, in which oxidative stress and glutamatergic hyperactivity are involved. N-Acetylcysteine (NAC) is a multitarget approved drug proved to be beneficial in the treatment of various mental disorders. Nevertheless, NAC has low membrane permeability and poor bioavailability and its limited delivery to the brain may explain inconsistencies in the literature. N-Acetylcysteine amide (AD4) is a synthetic derivative of NAC in which the carboxyl group was modified to an amide. The amidation of AD4 improved lipophilicity and blood-brain barrier permeability and enhanced its antioxidant properties. The purpose of this study was to investigate the effects of AD4 on behavioral and biochemical parameters in zebrafish anxiety models. Neither AD4 nor NAC induced effects on locomotion and anxiety-related parameters in the novel tank test. However, in the light/dark test, AD4 (0.001 mg/L) increased the time spent in the lit side in a concentration 100 times lower than NAC (0.1 mg/L). In the acute restraint stress protocol, NAC and AD4 (0.001 mg/L) showed anxiolytic properties without meaningful effects on oxidative status. The study suggests that AD4 has anxiolytic effects in zebrafish with higher potency than the parent compound. Additional studies are warranted to characterize the anxiolytic profile of AD4 and its potential in the management of anxiety disorders.

Modeling anxiety in healthy humans: a key intermediate bridge between basic and clinical sciences

Animal models of anxiety disorders are important for elucidating neurobiological defense mechanisms. However, animal models are limited when it comes to understanding the more complex processes of anxiety that are unique to humans (e.g., worry) and to screen new treatments. In this review, we outline how the Experimental Psychopathology approach, based on experimental models of anxiety in healthy subjects, can mitigate these limitations and complement research in animals. Experimental psychopathology can bridge basic research in animals and clinical studies, as well as guide and constrain hypotheses about the nature of psychopathology, treatment mechanisms, and treatment targets. This review begins with a brief review of the strengths and limitations of animal models before discussing the need for human models of anxiety, which are especially necessary to probe higher-order cognitive processes. This can be accomplished by combining anxiety-induction procedures with tasks that probe clinically relevant processes to identify neurocircuits that are potentially altered by anxiety. The review then discusses the validity of experimental psychopathology and introduces a methodological approach consisting of five steps: (1) select anxiety-relevant cognitive or behavioral operations and associated tasks, (2) identify the underlying neurocircuits supporting these operations in healthy controls, 3) examine the impact of experimental anxiety on the targeted operations in healthy controls, (4) utilize findings from step 3 to generate hypotheses about neurocircuit dysfunction in anxious patients, and 5) evaluate treatment mechanisms and screen novel treatments. This is followed by two concrete illustrations of this approach and suggestions for future studies.

A systematic review of in vitro cytokine production in eating disorders

BACKGROUND

Eating disorders (EDs) have been associated with alterations in cytokine concentrations and production. This review examines whether in vitro cytokine production (i) is altered in people with EDs compared to healthy participants; and (ii) changes in response to treatment?

METHODS

Using PRISMA guidelines, we systematically reviewed articles reporting group comparisons or longitudinal assessments of spontaneous and/or stimulated cytokine production in vitro in people with EDs.

RESULTS

Twelve studies were included. Cross-sectional results were mixed in anorexia nervosa. Only one study measured cytokine production in bulimia nervosa. Two longitudinal studies showed that daily yoghurt consumption increases phytohemagglutinin-stimulated interferon-γ production in anorexia nervosa.

CONCLUSION

The mixed results could be accounted for by variations in experimental design. Our findings suggest that cytokine production could possibly be modulated through dietary interventions. However, due to the methodological heterogeneity and shortcomings of the included studies, it seems unreasonable to draw further conclusions.

The roles of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) in predicting treatment remission in a Chinese Han population with generalized anxiety disorder

Neurotrophic factors, particularly brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF), are involved in neuroplasticity in the nervous system. To explore the characteristics of BDNF and GDNF and their roles in predicting treatment remission in a Chinese Han population with generalized anxiety disorder (GAD), 85 GAD patients were treated with escitalopram or venlafaxine randomly for 8 weeks. The serum BDNF/GDNF levels were detected, while Hamilton Anxiety Rating Scale (HAMA) scores were measured at baseline and after 8 weeks of treatment. The differences in serum BDNF/GDNF levels between GAD patients (n = 85) and healthy controls (n = 73) and between remission and nonremission were then compared. The serum BDNF levels were lower in GAD patients (1197.24 ± 367.41 µg/L) than in healthy controls (1378.09 ± 382.46 µg/L) (P < 0.05). The serum GDNF levels were also lower in GAD patients (10.19 ± 9.86 µg/L) than in healthy controls (13.73 ± 9.44 µg/L) (P < 0.05). The BDNF level was negatively correlated with baseline HAMA score (P < 0.05). The GDNF level was negatively correlated with baseline HAMA score (P < 0.05). The BDNF level was positively correlated with GDNF level (P < 0.05). Both baseline BDNF/GDNF levels in remission and nonremission showed no statistically significant differences. No significant correlation was found between baseline BDNF level and the HAMA reduction rate or between baseline GDNF levels and the HAMA reduction rate. Both serum BDNF and GDNF were demonstrated to be potential biomarkers of GAD, it seems that serum BDNF and GDNF levels can be used to assess the baseline anxiety severity of GAD but cannot serve as a factor to predict treatment remission.

A meta-analysis of cytokine concentrations in eating disorders

Cytokines are signalling molecules, which play an important role in both immune system function and brain development and function, and subsequently mental states and behaviour. Cytokines have been implicated in eating disorders (EDs) due to their role in psychological health, body weight and appetite regulation. This meta-analysis examined cross-sectional and longitudinal studies measuring concentrations of cytokines in individuals with EDs. Using PRISMA guidelines, we systematically reviewed relevant articles in PubMed, Web of Science, and MEDLINE. Random-effects meta-analyses were conducted for interleukin (IL)-1β, IL-6, transforming growth factor (TGF)-β, and tumor necrosis factor (TNF)-α, independently, firstly with all EDs combined and then stratified by ED diagnosis. Twenty-five studies were included: serum/plasma cytokine concentrations were measured in people with anorexia nervosa (AN) in 23 studies and bulimia nervosa (BN) in 4 studies. TNF-α and IL-6 were elevated in ED participants compared to healthy controls (HCs). Specifically, this pattern was seen only when comparing AN participants to HCs. Concentrations of these cytokines did not differ between people with BN and HCs. IL-1β and TGF-β did not differ between HCs and any ED group. Therefore, AN seems to be associated with elevated concentrations of TNF-α and IL-6. Considering the role of cytokines in appetite, mood regulation, and anxiety, these pro-inflammatory cytokines could be a potential future drug target to help people with AN, not only with weight gain, but also with various coexisting psychological problems. Future studies should consider confounding factors that affect cytokine concentrations and report ED-relevant clinical characteristics.

Comparing the efficacy of benzodiazepines and serotonergic anti-depressants for adults with generalized anxiety disorder: a meta-analytic review

INTRODUCTION

Generalized anxiety disorder (GAD) is a common form of anxiety disorder. Selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), and benzodiazepines (BZs) are the most commonly prescribed medications for GAD, but little is known about the relative efficacy of these pharmacological treatments. Areas covered: This study provides a meta-analytic review of the efficacy of these medications in the treatment of adults with GAD. A comprehensive literature search yielded 54 articles reporting 56 unique studies with 12,655 participants treated with either pill placebo (6,191 participants), SSRIs (16 trials, 2,712 participants), SNRIs (17 trials, 2,603 participants), or BZs (23 trials, 1,149 participants). The overall combined effect size was modest to moderate (Hedges' g = 0.37, p < 0.0001). Effect sizes decreased significantly over time. SSRIs (Hedges' g = 0.33) and SNRIs (Hedges' g = 0.36) demonstrated significantly lower effect sizes than BZs (Hedges' g = 0.50). These findings were not due to differences in treatment length or publication year. Expert opinion: The results of this study suggest that the most common forms of pharmacotherapy for adult GAD are moderately effective, with BZs being the most effective drug.