The neurobiology of social anxiety disorder: the relevance of fear and anxiety

New frontiers in the pharmacological treatment of social anxiety disorder in adults: an up-to-date comprehensive overview

INTRODUCTION

Social anxiety disorder (SAD) is associated with scarce functioning and poor quality of life. Although selective serotonin reuptake inhibitors (SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) are currently first-line treatments, side effects are common and affect treatment compliance in approximately 50% of patients. This review aimed to summarize data on the efficacy of unlabeled molecules for SAD treatment.

AREAS COVERED

Research in the main psychiatric databases was conducted (PubMed, PsychINFO, and EMBASE-Ovid) to select studies investigating the efficacy of marketed molecules not labeled for SAD treatment.

EXPERT OPINION

Pregabalin at high doses (450-600 mg/day) appears to be a reliable alternative strategy for SAD treatment. Among the SSRIs not labeled for SAD, citalopram showed the most promising results. Quetiapine, levetiracetam, and other antidepressants/serotonergic agents, such as fluoxetine, duloxetine, monoamine oxidase inhibitors, tricyclics, mirtazapine, atomoxetine, nefazodone, vilazodone, and buspirone, presented negative, limited, or contrasting results. Data on anticonvulsants, olanzapine, tiagabine, and ketamine were positive, but preliminary. The risk/benefit ratio must be considered in the prescription of unlabeled compounds; treatment with pregabalin may be associated with somnolence and dizziness. Future research may contribute to the identification of targeted molecules for the treatment of this disorder.

Mice can recognise water depths and will avoid entering deep water

Rodents are averse to bodies of water, and this aversion has been exploited in experiments designed to study stress in mice. However, a few studies have elucidated the characteristics of murine water aversion. In this study, we investigated how mice behave in and around areas filled with water. Using variants of the open field test that contained pools of water at corners or sides of the field, we recorded the movements of mice throughout the field under various conditions. When the water was 8 mm deep, the mice explored the water pool regardless of whether an object was placed within it, but when the water was 20 mm deep, the mice were less willing to enter it. When the mice were placed on a dry area surrounded by 3 mm-deep water, they explored the water, but when they were surrounded by 8 mm-deep water, they stayed within the dry area. Our results indicate that mice exhibit exploratory behaviours around water, they can recognise water depths and avoid unacceptably deep water, and their willingness to enter water may be reduced by situational anxiety. Our experimental method could be used to investigate water-related anxiety-like behaviours in mice.

The endocannabinoid system in social anxiety disorder: from pathophysiology to novel therapeutics

Social anxiety disorder (SAD) is a highly prevalent psychiatric disorder that presents with an early age of onset, chronic disease course, and increased risk of psychiatric comorbidity. Current treatment options for SAD are associated with low response rates, suboptimal efficacy, and possible risk of adverse effects. Investigation of new neurobiological mechanisms may aid in the identification of more specific therapeutic targets for the treatment of this disorder. Emerging evidence suggests that the endogenous cannabinoid system, also referred to as the endocannabinoid system (ECS), could play a potential role in the pathophysiology of SAD. This review discusses the known pathophysiological mechanisms of SAD, the potential role of the ECS in this disorder, current drugs targeting the ECS, and the potential of these novel compounds to enhance the therapeutic armamentarium for SAD. Further investigational efforts, specifically in human populations, are warranted to improve our knowledge of the ECS in SAD.

Sex-specific effects of social defeat stress on miRNA expression in the anterior BNST

Women are more likely to suffer from stress-related affective disorders than men, but the underlying mechanisms of sex differences remain unclear. Previous works show that microRNA (miRNA) profiles are altered in stressed animals and patients with depression and anxiety disorders. In this study, we investigated how miRNA expression in the anterior bed nucleus of stria terminalis (BNST) was affected by social defeat stress in female and male California mice (Peromyscus californicus). We performed sequencing to identify miRNA transcripts in the whole brain and anterior BNST followed by qPCR analysis to compare miRNA expression between control and stressed animals. The results showed that social defeat stress induced sex-specific miRNA expression changes in the anterior BNST. Let-7a, let-7f and miR-181a-5p were upregulated in stressed female but not male mice. Our study provided evidence that social stress produces distinct molecular responses in the BNST of males and females.

The risk of anxiety disorders in children of parents with severe psychiatric disorders: a systematic review and meta-analysis

BACKGROUND

Several studies have investigated the association between parental severe psychiatric disorders and anxiety disorder risk in offspring, but the findings across these studies have been inconsistent.

METHODS

Using the PRISMA guideline, a rigorous electronic and manual search was conducted in four electronic databases EMBASE, PubMed, PsychINFO, and Scopus to identify relevant studies. All observation studies (cohort and case-control studies) that examined the association between parental severe psychiatric disorders and the risk of offspring anxiety disorders were identified. Summary risk ratios (RRs) and 95% confidence intervals (95%CI) were synthesized using a fixed and random effect meta-analysis.

RESULTS

Twenty-five studies were included in the final analysis (14 cohort and 11 case-control studies). The meta-analysis showed that parental severe psychiatric disorder was associated with a higher risk of social phobia, panic, obsessive-compulsive, post-traumatic stress, separation anxiety, and generalized anxiety disorders in the offspring. When considering specific severe psychiatric disorders in parents as exposure, parental bipolar disorder was associated with an increased risk of obsessive-compulsive and generalized anxiety disorders in the offspring, whereas parental depressive disorder was associated with an increased risk of social phobia, separation anxiety, and generalized anxiety disorders in the offspring. Conversely, parental schizophrenia was not associated with offspring anxiety disorder CONCLUSION: This review suggests that the offspring of parents with severe psychiatric, bipolar, and depressive disorders are at an increased risk of developing a range of anxiety disorders. These findings suggest that targeted early screening and intervention programs are imperative in exposed offspring.

Amino acids profiles of children who stutter compared to their fluent sibling

Purpose: This study scrutinises the abundances of 9 neurological-related amino acids of the scalp hair of 35 (5 females, 30 males) children who stutter and 30 normally fluent children (age and sex matched).Methods: Samples of hair from children who stutter aged (5-9 years) were collected from Speech Clinic at King Abdullah Hospital. The control subjects were selected from the same families of children who stutter to exclude the effect of nutritional, environmental, and biological factors. Amino Acid Analyser was used to measure the concentrations of amino acids in acid hydrolysed hair samples.Results: results indicated that the concentrations of threonine, tyrosine, and isoleucine (p = 0.001, 0.001, 0.02 respectively) are lower in hair samples of people who stutter compared with samples of normal fluent speakers.Conclusion: The findings of this study could introduce a new treatment protocol including the supplementation of reduced nutritional elements.KEY POINTSConcentrations of amino acids (threonine, isoleucine, and tyrosine) in the hair samples of people who stutter were significantly lower than the concentrations in the hair samples of control group.Concentrations of amino acids (histidine and glutamate) in hair samples of people who stutter were lower than control group with low significant values.The concentrations of amino acids (phenylalanine, serine, glycine, aspartate, glutamate) were not significantly different between hair samples of stuttering group and control group.The findings of the current study will be helpful in designing a new treatment method based on the supplementation of deficient amino acids.

Association between Internet gaming disorder and generalized anxiety disorder

Introduction This study evaluates the association between generalized anxiety disorder (GAD) and Internet gaming disorder (IGD) and the role of behavior inhibition in young adults. Methods We recruited 87 people with IGD and a control group of 87 people without a history of IGD. All participants underwent a diagnostic interview based on the fifth edition of Diagnostic and Statistical Manual of Mental Disorders, IGD and GAD criteria, and completed a questionnaire on behavior inhibition, depression, and anxiety. Results Logistic regression revealed that adults with GAD were more likely (odds ratio = 8.11, 95% CI = 1.78-37.09) to have IGD than those without it. The OR decreased when controlling for behavior inhibition. IGD subjects with GAD had higher depressive and anxiety score than those without GAD. Conclusions GAD was associated with IGD. Comorbid GAD can contribute to higher emotional difficulty. GAD should be well-assessed and interventions planned when treating young adults with IGD. Behavioral inhibition confounds the association between GAD and IGD. Further study is necessary to evaluate how to intervene in behavioral inhibitions to attenuate the risk of GAD and IGD comorbidity.

Statins Promote Long-Term Recovery after Ischemic Stroke by Reconnecting Noradrenergic Neuronal Circuitry

Inhibitors of HMG-CoA reductase (statins), widely used to lower cholesterol in coronary heart and vascular disease, are effective drugs in reducing the risk of stroke and improving its outcome in the long term. After ischemic stroke, cardiac autonomic dysfunction and psychological problems are common complications related to deficits in the noradrenergic (NA) system. This study investigated the effects of statins on the recovery of NA neuron circuitry and its function after transient focal cerebral ischemia (tFCI). Using the wheat germ agglutinin (WGA) transgene technique combined with the recombinant adenoviral vector system, NA-specific neuronal pathways were labeled, and were identified in the locus coeruleus (LC), where NA neurons originate. NA circuitry in the atorvastatin-treated group recovered faster than in the vehicle-treated group. The damaged NA circuitry was partly reorganized with the gradual recovery of autonomic dysfunction and neurobehavioral deficit. Newly proliferated cells might contribute to reorganizing NA neurons and lead anatomic and functional recovery of NA neurons. Statins may be implicated to play facilitating roles in the recovery of the NA neuron and its function.

Neurobiological correlates of social anxiety disorder: an update

Social anxiety disorder (SAD) is a condition characterized by pervasiveness and impairment in social functioning, with a prevalence in the general population between 1.9% and 12.1%. The most consistent findings on its neurobiological underpinnings involve a wide range of neurotransmitters (serotonin, norepinephrine, glutamate, and GABA) and neuropeptides (oxytocin), but no comprehensive hypothesis is yet available. In particular, oxytocin is becoming increasingly established as a "prosocial neuropeptide" and, as such, is a major focus of current research, with a great range of therapeutic applications including SAD treatment. Specifically, the amygdala plays a pivotal role in conditioning and processing of fear, and exaggerated amygdala responses in SAD patients have been observed during various social-emotional stimuli. In addition to the amygdala, other brain areas of interest in SAD-related circuitry are represented by the medial prefrontal cortex, dorsal raphe, striatum, locus coeruleus, prefrontal cortex, insular cortex, and anterior cingulate cortex. The aim of this review is to provide an update on neurobiological correlates of SAD, with a special focus on neurotransmitters and brain areas possibly involved, and suggestions for future research that could lead to more specific therapeutic interventions.

Situation-based social anxiety enhances the neural processing of faces: evidence from an intergroup context

Social anxiety is the intense fear of negative evaluation by others, and it emerges uniquely from a social situation. Given its social origin, we asked whether an anxiety-inducing social situation could enhance the processing of faces linked to the situational threat. While past research has focused on how individual differences in social anxiety relate to face processing, we tested the effect of manipulated social anxiety in the context of anxiety about appearing racially prejudiced in front of a peer. Visual processing of faces was indexed by the N170 component of the event-related potential. Participants viewed faces of Black and White males, along with nonfaces, either in private or while being monitored by the experimenter for signs of prejudice in a 'public' condition. Results revealed a difference in the N170 response to Black and Whites faces that emerged only in the public condition and only among participants high in dispositional social anxiety. These results provide new evidence that anxiety arising from the social situation modulates the earliest stages of face processing in a way that is specific to a social threat, and they shed new light on how anxiety effects on perception may contribute to the regulation of intergroup responses.

Social anxiety in online and real-life interaction and their associated factors

Social anxiety was compared between online and real-life interaction in a sample of 2,348 college students. Severity of social anxiety in both real-life and online interaction was tested for associations with depression, Internet addiction, Internet activity type (gaming versus chatting), and scores on Behavioral Inhibition System (BIS)/Behavioral Activation System (BAS) scales. The results showed that social anxiety was lower when interacting online than when interacting offline. Depression, Internet addiction, and high BIS and BAS scores were associated with high social anxiety. The social anxiety decreased more in online interaction among subjects with high social anxiety, depression, BIS, and BAS. This result suggests that the Internet has good potential as an alternative medium for delivering interventions for social anxiety. Further, the effect of BIS on social anxiety is decreased in online interaction. More attention should be paid for BIS when the treatment for social anxiety is delivered online.

A novel social proximity test suggests patterns of social avoidance and gaze aversion-like behavior in BTBR T+ tf/J mice

The BTBR T+ tf/J (BTBR) inbred mouse strain displays a low sociability phenotype relevant to the first diagnostic symptom of autism, deficits in reciprocal social interactions. Previous studies have shown that BTBR mice exhibit reduced social approach, juvenile play, and interactive behaviors. The present study evaluated the behavior of the BTBR and C57BL/6J (B6) strains in social proximity. Subjects were closely confined and tested in four experimental conditions: same strain male pairs (Experiment 1); different strain male pairs (Experiment 2); same strain male pairs and female pairs (Experiment 3); same strain male pairs treated with an anxiolytic (Experiment 4). Results showed that BTBR mice displayed decreased nose tip-to-nose tip, nose-to-head and upright behaviors and increased nose-to-anogenital, crawl under and crawl over behaviors. These results demonstrated avoidance of reciprocal frontal orientations in the BTBR, providing a parallel to gaze aversion, a fundamental predictor of autism. For comparative purposes, Experiment 3 assessed male and female mice in a three-chamber social approach test and in the social proximity test. Results from the three-chamber test showed that male B6 and female BTBR displayed a preference for the sex and strain matched conspecific stimulus, while female B6 and male BTBR did not. Although there was no significant interaction between sex and strain in the social proximity test, a significant main effect of sex indicated that female mice displayed higher levels of nose tip-to-nose tip contacts and lower levels of anogenital investigation (nose-to-anogenital) in comparison to male mice, all together suggesting different motivations for sociability in males and females. Systemic administration of the anxiolytic, diazepam, decreased the frequency of two behaviors associated with anxiety and defensiveness, upright and jump escape, as well as crawl under behavior. This result suggests that crawl under behavior, observed at high levels in BTBR mice, is elicited by the aversiveness of social proximity, and possibly serves to avoid reciprocal frontal orientations with other mice.

Panic disorder, social anxiety disorder, and a possible medical syndrome previously linked to chromosome 13

BACKGROUND

Several studies have identified increased medical problems among individuals with panic disorder (PD). We previously found that specific conditions--interstitial cystitis (IC), mitral valve prolapse (MVP), migraines, and thyroid disorders--aggregated non-randomly among panic families (we called this the "PD syndrome") and that families with and without the syndrome were genetically distinguishable on chromosome 13. We present data from a new case-control study that replicates and extends the syndrome phenotype clinically.

METHODS

Probands with a definite diagnosis and family history of PD (n=219), social anxiety disorder (SAD; n=199), or both (n=173) and 102 control subjects with no personal/family history of anxiety were interviewed with the SADS-LA diagnostic instrument. Medical history was obtained via medical checklist and the family history screen; IC symptoms were assessed with criteria developed by the National Institute for Diabetes and Digestive and Kidney Diseases. Subjects and interviewers were unaware of the syndrome hypothesis; final best-estimate diagnoses were blind to syndrome data.

RESULTS

Probands with PD or SAD, as compared with control subjects, were five or more times as likely to report IC symptoms and twice as likely to report MVP and migraines (other genitourinary and cardiovascular problems were not elevated). First-degree relatives of probands with PD or SAD were also at increased risk for IC, MVP, thyroid problems, and headaches, regardless of whether the proband reported the same condition.

CONCLUSIONS

These findings are consistent with previous data supporting a PD syndrome and further suggest that this syndrome might include other anxiety disorders well.

Social phobia is associated with suicide attempt history in bipolar inpatients

OBJECTIVES

In an attempt to reduce the phenotypical heterogeneity in an ongoing genetic study of suicidal behavior, we investigated the impact of comorbid anxiety disorders on suicidal behavior in bipolar disorder (BD) patients.

METHODS

Anxiety disorders were compared in 406 BD I and BD II patients with or without lifetime history of suicide attempt.

RESULTS

Among anxiety disorders, only social phobia (SP) was significantly associated with history of suicide attempt in BD [p<0.001, odds ratio 4.26 (2.284-7.946)]. Moreover, onset of SP was found to precede onset of BD.

CONCLUSIONS

This result suggests that SP is an important risk factor for suicidal behavior in BD. Further studies are required to determine whether comorbid SP may help to identify a more homogeneous BD sub-group, especially when studies of suicidal behavior are conducted. A second question is whether SP identifies a sub-group of subjects with BD who have a more severe illness course and whether treatment of SP with selective serotonin reuptake inhibitor (SSRI) antidepressants is associated with improvement or worsening of the course of BD.

Categorical perception of anger and disgust facial expression is affected by non-clinical social anxiety: An ERP study

Anxiety has been associated with a bias for interpreting threatening information. Faces expressing anger seem to be more easily detected by socially anxious individuals than by non-anxious individuals. Similarly, disgust on a face may also reflect a negative social judgment. We tested the hypothesis that individuals displaying non-clinical social anxiety would be as sensitive to disgust as to anger interpretation by comparing individuals scoring high or low on the fear of social evaluation scale (FNE, Watson and Friend, 1969). Event-related potentials (ERP) were recorded in response to repetitions of a particular facial expression (e.g. anger) and in response to two deviating (rare) stimuli obtained by a morphing procedure, where one depicted the same emotion as the frequent stimulus, while the other depicted a different facial expression (e.g. disgust). The classic effect of categorical perception was reproduced: at a behavioral level, people detected more easily rare faces depicting a different emotion than faces depicting the same emotion. ERP results suggest that deviant faces depicting a different emotion evoked an earlier attentional N2b/P3a wave complex, together with an earlier and enhanced P3b. More interestingly, participants with non-clinical social anxiety manifested a reduced N2b wave when they had to detect a change in intensity of anger presentation. However, these individuals did not show facilitation to disengage from disgust when they have to detect angry faces, which was displayed by control participants. Implications and suggestions for further research about the role played by anger and disgust in psychopathology are outlined.

Aromatherapy and massage for antenatal anxiety: Its effect on the fetus

Antenatal anxiety has been linked to maternal hypothalamic-pituitary-adrenal axis changes which can affect fetal development and may have lasting effects on the child's psychological development. Treatments for anxiety have hitherto focused on psychotherapy techniques or antidepressant drugs but these do not always effect long term improvement. Aromatherapy and massage have successfully been used to produce significantly greater improvement in reduction of anxiety. Midwives may highlight anxiety in some of the mothers in their care and can incorporate the holistic approach of aromatherapy and massage into their practice. However, further research is required to establish the efficacy and cost-effectiveness of aromatherapy and massage in the antenatal period.

Genetic reduction of noradrenergic function alters social memory and reduces aggression in mice

Aberrant social behavior is a hallmark of many cognitive, mood, and neurological disorders, although the specific molecular mechanisms underlying the behavioral deficits are not well understood. The neurotransmitter noradrenaline (NA) has been implicated in some of these disorders, as well as in several aspects of social behavior in humans and animals. We tested dopamine beta-hydroxylase knockout (Dbh -/-) mice that lack NA in various social behavior paradigms. Dbh -/- mice have relatively normal performance in the elevated plus maze, light/dark box, and open field test - three measures of anxiety - and a social recognition test. In contrast, Dbh -/- mice displayed a specific deficit in a social discrimination task and had a nearly complete absence of resident-intruder aggression. These results indicate that intact NA signaling is required for some types of social memory and aggression, but that a lack of NA does not greatly affect anxiety in mice. Further exploration of NA deficits in neurological disease may reveal mechanisms of aberrant social behavior.

Automated apparatus for quantitation of social approach behaviors in mice

Mouse models of social dysfunction, designed to investigate the complex genetics of social behaviors, require an objective methodology for scoring social interactions relevant to human disease symptoms. Here we describe an automated, three chambered apparatus designed to monitor social interaction in the mouse. Time spent in each chamber and the number of entries are scored automatically by a system detecting photocell beam breaks. When tested with the automated equipment, juvenile male C57BL/6J mice spent more time in a chamber containing a stranger mouse than in an empty chamber (sociability), similar to results obtained by the observer scored method. In addition, automated scoring detected a preference to spend more time with an unfamiliar stranger than a more familiar conspecific (preference for social novelty), similar to results obtained by the observer scored method. Sniffing directed at the wire cage containing the stranger mouse correlated significantly with time spent in that chamber, indicating that duration in a chamber represents true social approach behavior. Number of entries between chambers did not correlate with duration of time spent in the chambers; entries instead proved a useful control measure of general activity. The most significant social approach behavior took place in the first five minutes of both the sociability and preference for social novelty tests. Application of these methods to C57BL/6J, DBA/2J and FVB/NJ adult males revealed that all three strains displayed tendencies for sociability and preference for social novelty. To evaluate the importance of the strain of the stranger mouse on sociability and preference for social novelty, C57BL/6J subject mice were tested either with A/J strangers or with C57BL/6J strangers. Sociability and preference for social novelty were similar with both stranger strains. The automated equipment provides an accurate and objective approach to measuring social tendencies in mice. Its use may allow higher-throughput scoring of mouse social behaviors in mouse models of social dysfunction.

Efficacy and safety of milnacipran in the treatment of generalized anxiety disorder: an open study

OBJECTIVE The aim of this open study was to assess the efficacy and safety of the serotonin-noradrenaline reuptake-inhibiting antidepressant, milnacipran, for the treatment of generalised anxiety disorder. METHODS Twelve patients, treated with milnacipran at doses from 30 to 150 mg/day for 8 weeks, were evaluated at baseline and after 1, 2, 3, 4, 6 and 8 weeks of treatment using the Hamilton Anxiety Rating (HAM-A) scale and a self-rating visual analogue scale. RESULTS Two patients dropped out early in the trial because of adverse effects. The 10 patients who completed the trial showed a marked improvement in anxiety symptoms with HAM-A scores being reduced from 21.6±6.5 (mean±SD) to 1.5±1.8 after 8 weeks. All of the patients who completed the 8 weeks of treatment had a reduction of at least 70% in their HAM-A score. Adverse effects, principally nausea, were mild and occurred early in the study, regressing as the study progressed. CONCLUSION These results suggest that milnacipran is effective and well tolerated in patients suffering from generalised anxiety disorder. A full-scale double-blind placebo trial is clearly warranted.