Practitioner Review: Differential susceptibility theory: might it help in understanding and treating mental health problems in youth?

Diathesis-stress models conceptualise individual differences in propensity for psychopathology as an interaction between environmental risk factors and intra-individual vulnerabilities. In contrast, the differential susceptibility theory and related frameworks view intra-individual differences as variations in sensitivity to the environments rather than merely vulnerability to them. Specifically, they suggest that more sensitive individuals are more affected by the quality of their context, whether positive or negative, than others who are less sensitive. Empirical research over the last two decades has found support for this notion in that greater sensitivity is associated with a greater risk of psychopathology in adverse contexts, but also with lower risk in positive environments. However, despite growing academic and public interest in this field, it is currently unclear to what extent the differential susceptibility model is relevant, or applicable, to clinical practice. The purpose of this review is to focus on the differential susceptibility theory as an alternative explanation of individual differences in mental health and examine its relevance in the treatment of mental health problems in young people. We provide an overview of differential susceptibility and related theories, and current relevant research in the field. We identify potential implications of differential susceptibility models for understanding and treating mental health problems in young people, whilst also highlighting important gaps in research that limit their application at present. Finally, we suggest directions for future research that will assist in the translation of differential susceptibility theories into clinical practice

Environmental sensitivity in children: development of the highly sensitive child scale and identification of sensitivity groups

A large number of studies document that children differ in the degree they are shaped by their developmental context with some being more sensitive to environmental influences than others. Multiple theories suggest that Environmental Sensitivity is a common trait predicting the response to negative as well as positive exposures. However, most research to date relied on more or less proximal markers of Environmental Sensitivity. In this paper we introduce a new questionnaire—the Highly Sensitive Child (HSC) scale—as a promising self-report measure of Environmental Sensitivity. After describing the development of the short 12-item HSC scale for children and adolescents, we report on the psychometric properties of the scale, including confirmatory factor analysis and test-retest reliability. After considering bivariate and multivariate associations with well-established temperament and personality traits, we apply Latent Class Analysis to test for the existence of hypothesised sensitivity groups. Analyses are conducted across five studies featuring four different UK-based samples ranging in age from 8-19 years and with a total sample size of N = 3,581. Results suggest the 12-item HSC scale is a psychometrically robust measure that performs well in both children and adolescents. Besides being relatively independent from other common traits, the Latent Class Analysis suggests that there are three distinct groups with different levels of Environmental Sensitivity—low (approx. 25-35%), medium (approx. 41-47%), and high (20-35%). Finally, we provide exploratory cut-off scores for the categorisation of children into these different groups which may be useful for both researchers and practitioners

Environmental sensitivity in children: development of the highly sensitive child scale and identification of sensitivity groups

A large number of studies document that children differ in the degree they are shaped by their developmental context with some being more sensitive to environmental influences than others. Multiple theories suggest that Environmental Sensitivity is a common trait predicting the response to negative as well as positive exposures. However, most research to date relied on more or less proximal markers of Environmental Sensitivity. In this paper we introduce a new questionnaire—the Highly Sensitive Child (HSC) scale—as a promising self-report measure of Environmental Sensitivity. After describing the development of the short 12-item HSC scale for children and adolescents, we report on the psychometric properties of the scale, including confirmatory factor analysis and test-retest reliability. After considering bivariate and multivariate associations with well-established temperament and personality traits, we apply Latent Class Analysis to test for the existence of hypothesised sensitivity groups. Analyses are conducted across five studies featuring four different UK-based samples ranging in age from 8-19 years and with a total sample size of N = 3,581. Results suggest the 12-item HSC scale is a psychometrically robust measure that performs well in both children and adolescents. Besides being relatively independent from other common traits, the Latent Class Analysis suggests that there are three distinct groups with different levels of Environmental Sensitivity—low (approx. 25-35%), medium (approx. 41-47%), and high (20-35%). Finally, we provide exploratory cut-off scores for the categorisation of children into these different groups which may be useful for both researchers and practitioners

A cross‐lagged twin study of emotional symptoms, social isolation and peer victimisation from early adolescence to emerging adulthood

Background Emotional symptoms, such as anxiety and depressive symptoms, are common during adolescence, often persist over time, and can precede the emergence of severe anxiety and depressive disorders. Studies suggest that a vicious cycle of reciprocal influences between emotional symptoms and interpersonal difficulties may explain why some adolescents suffer from persisting emotional symptoms. However, the role of different types of interpersonal difficulties, such as social isolation and peer victimisation, in these reciprocal associations is still unclear. In addition, the lack of longitudinal twin studies conducted on emotional symptoms during adolescence means that the genetic and environmental contributions to these relationships during adolescence remain unknown. Methods Participants (N = 15,869) from the Twins Early Development Study completed self-reports of emotional symptoms, social isolation and peer victimisation at 12, 16 and 21 years old. A phenotypic cross-lagged model examined reciprocal associations between variables over time, and a genetic extension of this model examined the aetiology of the relationships between variables at each timepoint. Results First, emotional symptoms were reciprocally and independently associated with both social isolation and peer victimisation over time, indicating that different forms of interpersonal difficulties uniquely contributed to emotional symptoms during adolescence and vice versa. Second, early peer victimisation predicted later emotional symptoms via social isolation in mid-adolescence, indicating that social isolation may constitute an intermediate pathway through which peer victimisation predicts longer-term emotional symptoms. Finally, individual differences in emotional symptoms were mostly accounted for by non-shared environmental factors at each timepoint, and both gene–environment and individual-specific environmental mechanisms were involved in the relationships between emotional symptoms and interpersonal difficulties. Conclusions Our study highlights the necessity to intervene early in adolescence to prevent the escalation of emotional symptoms over time and to consider social isolation and peer victimisation as important risk factors for the long-term persistence of emotional symptoms

Genome‑wide stress sensitivity moderates the stress‑depression relationship in a nationally representative sample of adults

We re-evaluate the findings of one of the most cited and disputed papers in gene-environment interaction (GxE) literature. In 2003, a paper was published in Science in which the authors demonstrated that the relationship between stress and depression is moderated by a polymorphism in the promoter region (5-HTTLPR) of the gene SLC6A4. Replication has been weak and led many to challenge the overall significance of GxE research. Here, we utilize data from Add Health, a large, nationally representative, and well-powered longitudinal study to re-examine the genetic determinants of stress sensitivity. We characterize environmental sensitivity using a genome-wide polygenic indicator rather than relying on one polymorphism in a single candidate gene. Our results provide support for the stress-diathesis perspective and validate the scientific contributions of the original paper. </div

Genetics of environmental sensitivity and its association with variations in emotional problems, autistic traits, and wellbeing

Greater environmental sensitivity has been associated with increased risk of mental health problems, especially in response to stressors, and lower levels of subjective wellbeing. Conversely, sensitivity also correlates with lower risk of emotional problems in the absence of adversity, and in response to positive environmental influences. Additionally, sensitivity has been found to correlate positively with autistic traits. Individual differences in environmental sensitivity are partly heritable, but it is unknown to what extent the aetiological factors underlying sensitivity overlap with those on emotional problems (anxiety and depressive symptoms), autistic traits and wellbeing. The current study used multivariate twin models and data on sensitivity, emotional problems, autistic traits, and several indices of psychological and subjective wellbeing, from over 2800 adolescent twins in England and Wales. We found that greater overall sensitivity correlated with greater emotional problems, autistic traits, and lower subjective wellbeing. A similar pattern of correlations was found for the Excitation and Sensory factors of sensitivity, but, in contrast, the Aesthetic factor was positively correlated with psychological wellbeing, though not with emotional problems nor autistic traits. The observed correlations were largely due to overlapping genetic influences. Importantly, genetic influences underlying sensitivity explained between 2 and 12% of the variations in emotional problems, autistic traits, and subjective wellbeing, independent of trait-specific or overlapping genetic influences. These findings encourage incorporating the genetics of environmental sensitivity in future genomic studies aiming to delineate the heterogeneity in emotional problems, autistic traits, and wellbeing

Factors associated with anxiety disorder comorbidity

Background Anxiety and depressive disorders often co-occur and the order of their emergence may be associated with different clinical outcomes. However, minimal research has been conducted on anxiety-anxiety comorbidity. This study examined factors associated with anxiety comorbidity and anxiety-MDD temporal sequence. Methods Online, self-report data were collected from the UK-based GLAD and COPING NBR cohorts (N = 38,775). Logistic regression analyses compared differences in sociodemographic, trauma, and clinical factors between single anxiety, anxiety-anxiety comorbidity, anxiety-MDD (major depressive disorder) comorbidity, and MDD-only. Additionally, anxiety-first and MDD-first anxiety-MDD were compared. Differences in familial risk were assessed in those participants with self-reported family history or genotype data. Results Anxiety-anxiety and anxiety-MDD had higher rates of self-reported anxiety or depressive disorder diagnoses, younger age of onset, and higher recurrence than single anxiety. Anxiety-MDD displayed greater clinical severity/complexity than MDD only. Anxiety-anxiety had more severe current anxiety symptoms, less severe current depressive symptoms, and reduced likelihood of self-reporting an anxiety/depressive disorder diagnosis than anxiety-MDD. Anxiety-first anxiety-MDD had a younger age of onset, more severe anxiety symptoms, and less likelihood of self-reporting a diagnosis than MDD-first. Minimal differences in familial risk were found. Limitations Self-report, retrospective measures may introduce recall bias. The familial risk analyses were likely underpowered. Conclusions Anxiety-anxiety comorbidity displayed a similarly severe and complex profile of symptoms as anxiety-MDD but distinct features. For anxiety-MDD, first-onset anxiety had an earlier age of onset and greater severity than MDD-first. Anxiety disorders and comorbidity warrant further investigation and attention in research and practice

A cross-lagged twin study of emotional symptoms, social isolation, and peer victimisation from early adolescence to emerging adulthood

Background Emotional symptoms, such as anxiety and depressive symptoms, are common during adolescence, often persist over time, and can precede the emergence of severe anxiety and depressive disorders. Studies suggest that a vicious cycle of reciprocal influences between emotional symptoms and interpersonal difficulties may explain why some adolescents suffer from persisting emotional symptoms. However, the role of different types of interpersonal difficulties, such as social isolation and peer victimisation, in these reciprocal associations is still unclear. In addition, the lack of longitudinal twin studies conducted on emotional symptoms during adolescence means that the genetic and environmental contributions to these relationships during adolescence remain unknown. Methods Participants (N = 15,869) from the Twins Early Development Study completed self-reports of emotional symptoms, social isolation and peer victimisation at 12, 16 and 21 years old. A phenotypic cross-lagged model examined reciprocal associations between variables over time, and a genetic extension of this model examined the aetiology of the relationships between variables at each timepoint. Results First, emotional symptoms were reciprocally and independently associated with both social isolation and peer victimisation over time, indicating that different forms of interpersonal difficulties uniquely contributed to emotional symptoms during adolescence and vice versa. Second, early peer victimisation predicted later emotional symptoms via social isolation in mid-adolescence, indicating that social isolation may constitute an intermediate pathway through which peer victimisation predicts longer-term emotional symptoms. Finally, individual differences in emotional symptoms were mostly accounted for by non-shared environmental factors at each timepoint, and both gene–environment and individual-specific environmental mechanisms were involved in the relationships between emotional symptoms and interpersonal difficulties. Conclusions Our study highlights the necessity to intervene early in adolescence to prevent the escalation of emotional symptoms over time and to consider social isolation and peer victimisation as important risk factors for the long-term persistence of emotional symptoms