The serotonin transporter promoter variant (5-HTTLPR) and childhood adversity are associated with the personality trait openness to experience

Functional Variation in the FAAH Gene Is Directly Associated with Subjective Well-Being and Indirectly Associated with Problematic Alcohol Use

Fatty acid amide hydrolase (FAAH) is an enzyme that degrades anandamide, an endocannabinoid that modulates mesolimbic dopamine release and, consequently, influences states of well-being. Despite these known interactions, the specific role of FAAH in subjective well-being remains underexplored. Since well-being is a dynamic trait that can fluctuate over time, we hypothesized that we could provide deeper insights into the link between FAAH and well-being using longitudinal data. To this end, we analyzed well-being data collected three years apart using the WHO (Ten) Well-Being Index and genotyped a functional polymorphism in the FAAH gene (rs324420, Pro129Thr) in a sample of 2822 individuals. We found that the A-allele of rs324420, which results in reduced FAAH activity and elevated anandamide levels, was associated with lower well-being scores at both time points (Wave I, B: -0.52, p = 0.007; Wave II, B: -0.41, p = 0.03, adjusted for age and sex). A subsequent phenome-wide association study (PheWAS) affirmed our well-being findings in the UK Biobank (N = 126,132, alternative C-allele associated with elevated happiness, p = 0.008) and revealed an additional association with alcohol dependence. In our cohort, using lagged longitudinal mediation analyses, we uncovered evidence of an indirect association between rs324420 and problematic alcohol use (AUDIT-P) through the pathway of lower well-being (indirect effect Boot: 0.015, 95% CI [0.003, 0.030], adjusted for AUDIT in Wave I). We propose that chronically elevated anandamide levels might influence disruptions in the endocannabinoid system-a biological contributor to well-being-which could, in turn, contribute to increased alcohol intake, though multiple factors may be at play. Further genetic studies and mediation analyses are needed to validate and extend these findings.

The neurobiology of openness as a personality trait

Openness is a multifaceted behavioral disposition that encompasses personal, interpersonal, and cultural dimensions. It has been suggested that the interindividual variability in openness as a personality trait is influenced by various environmental and genetic factors, as well as differences in brain functional and structural connectivity patterns along with their various associated cognitive processes. Alterations in degree of openness have been linked to several aspects of health and disease, being impacted by both physical and mental health, substance use, and neurologic conditions. This review aims to explore the current state of knowledge describing the neurobiological basis of openness and how individual differences in openness can manifest in brain health and disease.

Ontological Adaptation in Transition to Adulthood: A Theoretical Framework for Integrating Phenomenology and Neuroscience in Psychosis Research

In this theoretical review, the neurodevelopmental model of psychotic disorders is considered within the framework of ontological development, referring to the individual-level construction of a sense of reality regarding identity and worldview. Following Erikson's theory of development, the challenge of forging a personal and social identity is a developmental process typical of late adolescence and early adulthood. Accompanying this process is a developmentally normal increase in exploratory and risk-taking behavior, which sometimes includes challenging and defying cultural norms. Although many aspects of ontological adaptation are developmentally appropriate, we argue that psychopathology such as psychosis can be rooted in an abnormal deviation of this process, in which aberrant salience accelerates the typical drive to develop a meaningful sense of identity, leading to delusion formation. By placing psychosis onset within a broader context of normal development, this model offers a humanistic approach for understanding experiences of new onset of psychotic disorders.

The cannabinoid receptor-1 gene interacts with stressful life events to increase the risk for problematic alcohol use

Problematic alcohol use is a major contributor to the global burden of death and disabilities, and it represents a public health concern that has grown substantially following the COVID-19 pandemic. The available treatment options remain limited and to develop better pharmacotherapies for alcohol misuse we need to identify suitable biological targets. Previous research has implicated the brain’s endocannabinoid system (ECS) in psychiatric and stress-related outcomes, including substance use and habituation to repeated stress. Moreover, genetic variants in the cannabinoid-1 receptor gene (CNR1; CB1R) have been associated with personality traits, which are in turn predictors of substance use disorders. To date, however, no human genome-wide association study has provided evidence for an involvement of the ECS in substance use outcomes. One reason for this ECS-related “missing heritability” may be unexamined gene-environment interactions. To explore this possibility, we conducted cross-sectional analyses using DNA samples and stress-exposure data from a longitudinal Swedish population-based study (N = 2,915). Specifically, we genotyped rs2023239, a functional C/T single nucleotide polymorphism in CNR1, previously reported to be associated with CNR1 binding in the brain, subjective reward following alcohol intake, and alcohol cue-elicited brain activation. Our two outcomes of interest were (i) problematic alcohol use based on the Alcohol Use Disorders Identification Test (AUDIT), and (ii) personality trait scores based on the Five Factor Model. We found no baseline association between rs2023239 and problematic alcohol use or personality traits. However, there was a clear trend for interaction between rs2023239’s risk allele (C) and stressful life events (SLEs) in both childhood and adulthood, which predicted problematic alcohol use. Although not significant, there was also some indication that the risk allele interacted with child SLEs to increase scores on neuroticism. Our study supports the notion that the ECS can affect alcohol intake behaviors by interacting with life adversities and is—to the best of our knowledge—the first to focus on the interaction between CNR1 and stressors in both childhood and adulthood in humans. Further studies are warranted to confirm these findings.

Association of Serotonin Transporter Gene (5-HTTLPR/rs25531) Polymorphism with Comorbidities of Panic Disorder

INTRODUCTION

Panic disorder (PD) has many comorbidities such as depression, bipolar disorder (BPD), and agoraphobia (AG). PD is a moderately heritable anxiety disorder whose pathogenesis is not well understood. Recently, a tri-allelic serotonin transporter (5-HTTLPR/rs25531) polymorphism was reported to be more sensitive to personality traits compared to the bi-allelic 5-HTTLPR polymorphism. We hypothesized that the 5-HTTLPR/rs25531 polymorphism may lead to a pathological anxious state depending on the presence or absence of a comorbidity in PD.

METHODS

In this study, we investigated the relationship between comorbidities in PD and tri-allelic 5-HTTLPR polymorphisms. A total of 515 patients with PD (148 males, 367 females) were genotyped, and the Revised NEO Personality Inventory as well as anxiety-related psychological tests were administered. Depression, BPD, and AG were diagnosed as comorbidities.

RESULTS

For the tri-allele 5-HTTLPR genotype, a significant interaction effect was found between openness to experience and comorbid depression. Examination of the interaction between AG and the tri-allelic 5-HTTLPR genotype revealed that L' allele carriers are associated with higher trait anxiety than the S'S' genotype group in PD without AG.

CONCLUSION

Some anxiety and personality traits can be characterized by the tri-allelic gene effect of 5-HTTLPR. These results suggest that tri-allelic 5-HTTLPR genotypes have genetic effects on the presence of comorbidities of PD.

Stressful life events and openness to experience: Relevance to depression

BACKGROUND

Stressful life events are known as risk factors for depression, though there is considerable heterogeneity in how people respond to stress. Previous studies have found an association between experience of stressful life events and the personality trait of openness to experience, which itself has been associated with intelligence, creativity, risk-taking, and other clinically relevant behaviors. In this study we explore the association between stressful life events and openness to experience as a potential developmental pathway to depression in the Amish and Mennonites, rural populations with high degree of social and environmental homogeneity.

METHODS

Participants in the Amish Connectome Project (n=531) were assessed with the NEO personality inventory, Beck Depression Inventory, Maryland Trait and State Depression scales, a Life Stressors Inventory, and cognitive tests.

RESULTS

We found that stressful life events were significantly associated with openness to experience; that participants with a history of depression exhibited higher levels of openness; and that openness to experience was related to overall intelligence but not processing speed or working memory. We found evidence that openness to experience partially mediates the relationship between stressful life events and depression.

LIMITATIONS

This was a cross-sectional study, limiting interpretation of causal pathways. High levels of inter-relatedness among participants may have led to exaggerated effects compared to the general population.

CONCLUSIONS

Together these findings indicate a complex developmental influence of major stressful life events, which paradoxically by enhancing openness may be associated with both greater intellectual engagement as well as psychopathology.

Personality traits and polymorphisms of genes coding neurotransmitter receptors or transporters: review of single gene and genome-wide association studies

BACKGROUND

The most popular tool used for measuring personality traits is the Five-Factor Model (FFM). It includes neuroticism, extraversion, openness, agreeableness and conscientiousness. Many studies indicated the association of genes encoding neurotransmitter receptors/transporters with personality traits. The relationship connecting polymorphic DNA sequences and FFM features has been described in the case of genes encoding receptors of cannabinoid and dopaminergic systems. Moreover, dopaminergic system receives inputs from other neurotransmitters, like GABAergic or serotoninergic systems.

METHODS

We searched PubMed Central (PMC), Science Direct, Scopus, Cochrane Library, Web of Science and EBSCO databases from their inception to November 19, 2020, to identify original studies, as well as peer-reviewed studies examining the FFM and its association with gene polymorphisms affecting the neurotransmitter functions in central nervous system.

RESULTS

Serotonin neurons modulate dopamine function. In gene encoding serotonin transporter protein, SLC6A4, was found polymorphism, which was correlated with openness to experience (in Sweden population), and high scores of neuroticism and low levels of agreeableness (in Caucasian population). The genome-wide association studies (GWASs) found an association of 5q34-q35, 3p24, 3q13 regions with higher scores of neuroticism, extraversion and agreeableness. However, the results for chromosome 3 regions are inconsistent, which was shown in our review paper.

CONCLUSIONS

GWASs on polymorphisms are being continued in order to determine and further understand the relationship between the changes in DNA and personality traits.

Genetic modulation of facial emotion recognition in borderline personality disorder

Facial emotion recognition (FER) has been described to be impaired in borderline personality disorder (BPD), especially for neutral faces. Genetic modulation of FER has been studied in healthy individuals and some psychiatric conditions, but no genetic association studies have been conducted in BPD hitherto. The main objective of our study was to explore the influence of the serotonin-transporter-linked promoter region (5HTTLPR) and catechol-o-methyltransferase (COMT) Val158Met on facial emotion processing among BPD patients. To that end, seventy-six BPD outpatients were asked to complete a computer-based facial affect recognition task, representing four emotions (neutral, happy, fearful or angry). Accuracy of FER and perceptual biases were calculated. The 5HTTLPR and COMT Val158Met polymorphisms were genotyped using saliva samples. Individuals with the high-activity serotonin-transporter genotype and those with the low-activity COMT genotype had significantly more difficulties identifying neutral faces; the former showed stronger bias to perceive neutral faces as happy, and the latter, neutral faces as fearful. Interestingly, the perceptual biases observed in our patients are similar to previous reports in healthy individuals. The authors propose that the ability to accurately recognize neutral faces might be a possible endophenotype of BPD. Sex-genotype interactions were also observed in relation to angry faces and 5HTTLPR, and neutral faces and COMT Val158Met polymorphisms, in line with sex-related differences previously described for both polymorphisms in relation to FER and other cognitive and behavioral outcomes. The impact of inaccurate FER on psychosocial functioning and potential interventions are also discussed.

Associations Among Monoamine Neurotransmitter Pathways, Personality Traits, and Major Depressive Disorder

Major depressive disorder (MDD) is a complex psychiatric disease requiring multidisciplinary approaches to identify specific risk factors and establish more efficacious treatment strategies. Although the etiology and pathophysiology of MDD are not clear until these days, it is acknowledged that they are almost certainly multifactorial and comprehensive. Monoamine neurotransmitter system dysfunction and specific personality traits are independent risk factors for depression and suicide. These factors also demonstrate complex interactions that influence MDD pathogenesis and symptom expression. In this review, we assess these relationships with the aim of providing a reference for the development of precision medicine.

Phenomenological contribution to understanding of vocally disruptive behaviour: A clinical case study in a patient with dementia

BACKGROUND

Behavioural and psychological symptoms of dementia (BPSD) cause great suffering in patients and their families. Phenomenology can help clarify the diagnosis and propose some new therapeutic responses using Daseinsanalyse. Separation issues understood using the phenomenological description of the melancholic type (MT) by Tellenbach may further shed light on our understanding of depression in dementia.

SUBJECT AND METHODS

In a 90-year-old woman presenting with advanced (Clinical Dementia Rating 3) mixed dementia and BPSD in the form of vocally disruptive behaviour (VDB), we discuss separation anxiety as the aetiopathogenic hypothesis. Depression and BPSD were assessed using the Neuropsychiatric Inventory, Cornell scale, and Montgomery-Åsberg Depression Rating Scale to confirm our second phenomenological diagnostic hypothesis, ie, melancholy. The Big Five Inventory scale filled in by a proxy was also used to evaluate the patient's premorbid personality. We then propose an explanatory frame of VDB and depression through the standard phenomenological assessment of its relation to time, space, self, and other.

RESULTS

Confirming MT, we found an inhibited temperament and low openness to experience in the patient, as well as a symbiotic relationship with a close relative (the other).

CONCLUSION

Separation anxiety may well explain the patient's MT expressed by VDB. Melancholic type and her symbiotic relationship led to a situation unbearable to the patient and her close relative unable to delegate care to a specialized team.

RUNNING HEAD

Phenomenology in vocally disruptive behaviour in dementia. We have found new explanations in similar clinical cases in dementia as follows. A patient presenting with vocally disruptive behaviour has a melancholic type, a behavioural-inhibited temperament, and marital violence in the past. Phenomenology may help explain this profile with neurobiological disorders. The life trajectory, from childhood into older age, must be taken into account to understand behavioural and psychological symptoms of dementia.