Serotonin transporter gene (SLC6A4) variation and sensory processing sensitivity-Comparison with other anxiety-related temperamental dimensions

High-fat diet, microbiome-gut-brain axis signaling, and anxiety-like behavior in male rats

Obesity, associated with the intake of a high-fat diet (HFD), and anxiety are common among those living in modern urban societies. Recent studies suggest a role of microbiome-gut-brain axis signaling, including a role for brain serotonergic systems in the relationship between HFD and anxiety. Evidence suggests the gut microbiome and the serotonergic brain system together may play an important role in this response. Here we conducted a nine-week HFD protocol in male rats, followed by an analysis of the gut microbiome diversity and community composition, brainstem serotonergic gene expression (tph2, htr1a, and slc6a4), and anxiety-related defensive behavioral responses. We show that HFD intake decreased alpha diversity and altered the community composition of the gut microbiome in association with obesity, increased brainstem tph2, htr1a and slc6a4 mRNA expression, including in the caudal part of the dorsomedial dorsal raphe nucleus (cDRD), a subregion previously associated with stress- and anxiety-related behavioral responses, and, finally, increased anxiety-related defensive behavioral responses. The HFD increased the Firmicutes/Bacteroidetes ratio relative to control diet, as well as higher relative abundances of Blautia, and decreases in Prevotella. We found that tph2, htr1a and slc6a4 mRNA expression were increased in subregions of the dorsal raphe nucleus in the HFD, relative to control diet. Specific bacterial taxa were associated with increased serotonergic gene expression in the cDRD. Thus, we propose that HFD-induced obesity is associated with altered microbiome-gut-serotonergic brain axis signaling, leading to increased anxiety-related defensive behavioral responses in rats.

Sensory Processing Sensitivity and the Importance of Individuality and Personality in Veterinary Medicine

Sensory processing sensitivity (SPS) is a personality trait described in humans and dogs that mediates how individuals are affected by experiences. It involves being aware of subtle stimuli, high emotional intensity and empathy, and deeper processing of information. Recognizing individuals scoring higher in SPS is likely to help better diagnose, treat, and prevent both psychological (behavioral) and physical problems, leading to increased welfare and quality of life of the animal and its surroundings.

The role of epigenetics in anxiety disorders

Anxiety disorders (ADs) are extremely common psychiatric conditions that frequently co-occur with other physical and mental disorders. The pathophysiology of ADs is multifaceted and involves intricate connections among biological elements, environmental stimuli, and psychological mechanisms. Recent discoveries have highlighted the significance of epigenetics in bridging the gap between multiple risk factors that contribute to ADs and expanding our understanding of the pathomechanisms underlying ADs. Epigenetics is the study of how changes in the environment and behavior can have an impact on gene function. Indeed, researchers have found that epigenetic mechanisms can affect how genes are activated or inactivated, as well as whether they are expressed. Such mechanisms may also affect how ADs form and are protected. That is, the bulk of pharmacological trials evaluating epigenetic treatments for the treatment of ADs have used histone deacetylase inhibitors (HDACi), yielding promising outcomes in both preclinical and clinical studies. This review will provide an outline of how epigenetic pathways can be used to treat ADs or lessen their risk. It will also present the findings from preclinical and clinical trials that are currently available on the use of epigenetic drugs to treat ADs.

The Hysteric and the HSP

This paper examines twenty-first-century research on sensory processing sensitivity (SPS) alongside mid-nineteenth-century research on hysteria. Doing so sheds light on how we have long thought of sensorial-emotional experience as progressing along a medical narrative from cause to cure. Today's rhetoric around the highly sensitive person (HSP) begins to diverge from the rhetoric around hysteria through the theorized cause and the dismissal of the need for a cure. When current perspectives remove the emphasis on a cure, the narrative emphasizes a broader need for social-emotional learning and cultural revision to stigma around sensitivity.

Sensory Processing Sensitivity and Gastrointestinal Symptoms in Japanese Adults

BACKGROUND

Sensory processing sensitivity is a personality or temperamental trait defined as individual differences in the tendency to perceive and process both positive and negative stimuli and experiences. Studies have shown that high sensitivity is correlated with psychosocial health, including depression and anxiety. However, its relationship with physical health has not been clarified. To fill this gap, using a large sample size with sufficient statistical power, an adult sample not including university students, and a range of covariates, this study examined the association between gastrointestinal symptoms as an indicator of physical health and sensory processing sensitivity.

METHODS

In this cross-sectional study, the participants were 863 Japanese adults (female = 450; male = 413; M_age = 30.4 years; SD = 4.9) who completed a web-based questionnaire. We statistically controlled for sociodemographic characteristics and examined whether sensory processing sensitivity is correlated with gastrointestinal symptoms.

RESULTS

The results showed that highly sensitive individuals were more likely to experience a wide range of gastrointestinal symptoms in the past week, including reflux symptoms, abdominal pain, indigestion symptoms, diarrhea symptoms, and constipation symptoms, even when statistically controlling for the participants' sociodemographic characteristics.

CONCLUSIONS

Our findings suggest that high sensory processing sensitivity is associated with physical health. Some of the potential causes of this are also discussed.

Personality Profile of the Self-Identified Highly Sensitive Person

Abstract. The current paper presents a detailed examination of a lay theory perspective on the Sensory-Processing-Sensitivity (SPS) personality profile within the Five-Factor Model (FFM) of personality. The lay SPS personality profile was assessed by asking self-identified highly sensitive people to rate themselves on a Five-Factor Model questionnaire (NEO-PI-3). We applied the NEO-PI-3 norms (domains and facets) and examined the inter-rater agreement of the facets. The sample consisted of 560 (female: 86.43%, Mage = 37.36 years, SDage = 6.64 years, 18.17–47.42 years) self-identified highly sensitive adults. Six facets, in particular, stood out with good and very good inter-rater agreement: participants fell within the highest 23% of the population on facets Fantasy, Aesthetics, Feelings (Openness to Experience); Anxiety, Depression (Neuroticism); and the lowest 23% of the population on the facet Gregariousness (Extraversion).

A neural model of vulnerability and resilience to stress-related disorders linked to differential susceptibility

Expert opinion remains divided concerning the impact of putative risk factors on vulnerability to depression and other stress-related disorders. A large body of literature has investigated gene by environment interactions, particularly between the serotonin transporter polymorphism (5-HTTLPR) and negative environments, on the risk for depression. However, fewer studies have simultaneously investigated the outcomes in both negative and positive environments, which could explain some of the inconclusive findings. This is embodied by the concept of differential susceptibility, i.e., the idea that certain common gene polymorphisms, prenatal factors, and traits make some individuals not only disproportionately more susceptible and responsive to negative, vulnerability-promoting environments, but also more sensitive and responsive to positive, resilience-enhancing environmental conditions. Although this concept from the field of developmental psychology is well accepted and supported by behavioral findings, it is striking that its implementation in neuropsychiatric research is limited and that underlying neural mechanisms are virtually unknown. Based on neuroimaging studies that examined how factors mediating differential susceptibility affect brain function, we posit that environmental sensitivity manifests in increased salience network activity, increased salience and default mode network connectivity, and increased salience and central executive network connectivity. These changes in network function may bring about automatic exogenous attention for positive and negative stimuli and flexible attentional set-shifting. We conclude with a call to action; unraveling the neural mechanisms through which differential susceptibility factors mediate vulnerability and resilience may lead us to personalized preventive interventions.

The Associations Between Sensory Processing Sensitivity and the Big Five Personality Traits in a Japanese Sample

Abstract. Sensory processing sensitivity (SPS) is a temperament trait characterized by deeper processing of sensory information, being easily overstimulated, stronger emotional reactivity, and more awareness of subtle stimuli. Many studies on Western samples have associated SPS and/or its three components (i.e., low sensory threshold [LST], ease of excitation [EOE], and aesthetic sensitivity [AES]) with the Big Five personality traits, but cultural factors may influence these relationships. This study surveyed a Japanese sample ( N = 1,626) to investigate the associations. Bivariate correlation analyses found that AES had a negatively weak correlation with neuroticism, while it was positively correlated with openness (strongly), extraversion, agreeableness (moderately), and conscientiousness (weakly). LST and EOE had strong positive correlations with neuroticism and moderate negative or weak correlations with the other four traits. The canonical correlation analysis revealed commonality between the constructs of about 55%. While some results were consistent with those of the former studies, others were not. The results contrary to studies on Western samples might be explained by the differences between collectivist and individualist cultures, biological differences, and/or measurement weaknesses.

Dental Anxiety and Higher Sensory Processing Sensitivity in a Sample of German Soldiers with Inflammatory Periodontal Disease

(1) Background: Dental anxiety with disease value usually leads to avoidance of dental treatment. For the initial diagnosis of the level of anxiety, questionnaires such as the Hierarchical Anxiety Questionnaire (HAQ) are suitable. The construct of sensory processing sensitivity (SPS) describes a general trait in which people with a higher degree of SPS perceive information more strongly and process it more thoroughly. (2) Methods: This cross-sectional study evaluated the relationship between dental anxiety and higher levels of SPS in 116 soldiers referred with different stages of periodontitis for mandatory dental fitness before military deployment. (3) Results: The proportion of patients with periodontitis in stage III + IV was 39% and in stage I + II was 27%. The mean cumulative values of the questionnaires were 20.9 ± 10.6 for HAQ and 27.7 ± 16.0 for SPS. Eleven moderately anxious patients had a SPS value of 37.4 ± 13.5 and 10 highly anxious patients had a value of 36.3 ± 14.1. Patients diagnosed with stage III + IV periodontitis showed significantly higher values on the SPS subscale Low Sensory Threshold (LST), which describes overstimulation by external sensory stimuli, compared to patients with stage I + II periodontitis. Dental anxiety showed moderately significant correlations with the SPS subscale Ease of Excitation (EOE), which measures emotional reactivity to physiological stimuli. (4) Conclusions: Due to the frequency of dental anxiety and higher sensitivity in patients with severe periodontitis, it is useful to record said frequency.

Serotonin transporter gene (SLC6A4) variation and sensory processing sensitivity-Comparison with other anxiety-related temperamental dimensions

Background

The short (s) allele of the 5‐HTTLPR polymorphism in the promoter region of the human serotonin transporter (5‐HTT) gene SLC6A4 has previously been associated with anxiety‐related personality dimensions. However, this relationship has not been confirmed in all studies and may be modified by environmental circumstances and/or psychiatric illness. This study examined whether the temperamental trait sensory processing sensitivity (SPS), characterized by increased responsivity to environmental stimuli, is related to 5‐HTTLPR/rs25531 genotype.

Methods

5‐HTTLPR and rs25531 genotypes, level of SPS, self‐reported Revised NEO Personality Inventory (NEO‐PI‐R) and Temperament and Character Inventory (TCI) personality profiles, and symptoms of psychological distress (SCL‐90R Global Severity Index) were determined for 405 healthy volunteers.

Results

Sensory processing sensitivity was highly correlated with the anxiety‐related dimensions of the NEO‐PI‐R and the TCI models of personality, Neuroticism, and Harm Avoidance, respectively. However, the level of SPS was not associated with the combined 5‐HTTLPR and rs25531 s′/s′ genotype. Neuroticism and Harm Avoidance were also not associated with 5‐HTTLPR/rs25531 s′/s′ genotype. Correcting for symptoms of psychological distress had no effect on the relationships between personality and genotype.

Conclusion

The level of SPS was not associated with serotonin transporter gene variation. Further, combined 5‐HTTLPR and rs25531 genotype was not associated with other anxiety‐related dimensions.