ADHD symptoms in healthy adults are associated with stressful life events and negative memory bias

Inflammation and emotion regulation: a narrative review of evidence and mechanisms in emotion dysregulation disorders

Emotion dysregulation (ED) describes a difficulty with the modulation of which emotions are felt, as well as when and how these emotions are experienced or expressed. It is a focal overarching symptom in many severe and prevalent neuropsychiatric diseases, including bipolar disorders (BD), attention deficit/hyperactivity disorder (ADHD), and borderline personality disorder (BPD). In all these disorders, ED can manifest through symptoms of depression, anxiety, or affective lability. Considering the many symptomatic similarities between BD, ADHD, and BPD, a transdiagnostic approach is a promising lens of investigation. Mounting evidence supports the role of peripheral inflammatory markers and stress in the multifactorial aetiology and physiopathology of BD, ADHD, and BPD. Of note, neural circuits that regulate emotions appear particularly vulnerable to inflammatory insults and peripheral inflammation, which can impact the neuroimmune milieu of the central nervous system. Thus far, few studies have examined the link between ED and inflammation in BD, ADHD, and BPD. To our knowledge, no specific work has provided a critical comparison of the results from these disorders. To fill this gap in the literature, we review the known associations and mechanisms linking ED and inflammation in general, and clinically, in BD, ADHD, and BD. Our narrative review begins with an examination of the routes linking ED and inflammation, followed by a discussion of disorder-specific results accounting for methodological limitations and relevant confounding factors. Finally, we critically discuss both correspondences and discrepancies in the results and comment on potential vulnerability markers and promising therapeutic interventions.

Anhedonia as a transdiagnostic symptom across psychological disorders: a network approach

BACKGROUND

Anhedonia is apparent in different mental disorders and is suggested to be related to dysfunctions in the reward system and/or affect regulation. It may hence be a common underlying feature associated with symptom severity of mental disorders.

METHODS

We constructed a cross-sectional graphical Least Absolute Shrinkage and Selection Operator (LASSO) network and a relative importance network to estimate the relationships between anhedonia severity and the severity of symptom clusters of major depressive disorder (MDD), anxiety sensitivity (AS), attention-deficit hyperactivity disorder (ADHD), and autism spectrum disorder (ASD) in a sample of Dutch adult psychiatric patients (N = 557).

RESULTS

Both these networks revealed anhedonia severity and depression symptom severity as central to the network. Results suggest that anhedonia severity may be predictive of the severity of symptom clusters of MDD, AS, ADHD, and ASD. MDD symptom severity may be predictive of AS and ADHD symptom severity.

CONCLUSIONS

The results suggest that anhedonia may serve as a common underlying transdiagnostic psychopathology feature, predictive of the severity of symptom clusters of depression, AS, ADHD, and ASD. Thus, anhedonia may be associated with the high comorbidity between these symptom clusters and disorders. If our results will be replicated in future studies, it is recommended for clinicians to be more vigilant about screening for anhedonia and/or depression severity in individuals diagnosed with an anxiety disorder, ADHD and/or ASD.

Emotional and sensory dysregulation as a possible missing link in attention deficit hyperactivity disorder: A review

Attention Deficit Hyperactivity Disorder (ADHD) is a common developmental disorder affecting 5-7% of adults and children. We surveyed the literature to examine ADHD through three pillars: developmental characteristics, symptomatology, and treatment strategies. Firstly, in terms of developmental characterstics, early life stress may increase the risk of developing ADHD symptoms according to animal models' research. Secondly, the current core symptoms of ADHD are comprised of inattention, hyperactivity, and impulsivity. However, the up-to-date literature indicates individuals with ADHD experience emotional and sensory dysregulation as well, which early-life stress may also increase the risk of. Finally, we discuss the therapeutic benefits of methylphenidate on both the current core ADHD symptoms and the sensory and emotional dysregulation found in those with ADHD. In summation, we surveyed the recent literature to analyze (i) the potential role of early-life stress in ADHD development, (ii) the involvement of emotional and sensory dysregulation in ADHD symptomatology and finally, (iii) the therapeutic intervention with methylphenidate, aiming to reduce the potential effect of early life stress in ADHD, and mainly emotional and sensory dysregulation. The apparent but currently less recognized additional symptoms of emotional and sensory dysregulation in ADHD call for further investigation of these possible causes and thus increasing treatments efficacy in individuals with ADHD.

The role of inflammatory markers and cortisol in the association between early social cognition abilities and later internalising or externalising problems: Evidence from a UK birth cohort

OBJECTIVE

Deficits in social cognition are associated with internalising (emotional and peer problems) and externalising (conduct problems and hyperactivity/inattention) symptoms in youth. It has been suggested that stress may be one of the mechanisms underlying these associations. However, no empirical studies have investigated if physiological stress can explain the prospective associations between social cognition deficits and internalising and externalising symptoms in the general youth population. This study addressed this question and focused on two indicators of physiological stress, dysregulated diurnal cortisol patterns and systemic inflammation.

METHOD

Participants were 714 individuals from the Avon Longitudinal Study of Parents and Children (ALSPAC), a UK population-based birth cohort. Bayesian structural equation modelling was used to investigate a) the associations of social cognition abilities at ages 8, 11, and 14 years with internalising and externalising problems at age 17 years and b) the potential mediating effects of cortisol parameters at age 15 years and inflammatory markers [interleukin 6 (IL-6) and C-reactive protein (CRP)] at ages 9 and 16 years.

RESULTS

We found that social cognition difficulties were associated with later internalising and externalising problems. Flattened diurnal cortisol slope was associated with hyperactivity/inattention problems two years later. Lower morning cortisol partially mediated the direct association between social communication deficits at 8 years and hyperactivity/inattention and conduct problems at 17 years, even after adjustments for inflammation and confounders (for hyperactivity/inattention: indirect effect = 0.07, 95% CI [0.00, 0.18], p = .042; for conduct problems: indirect effect = 0.04, 95% CI [0.00, 0.11], p = .040). We did not find a significant association between systemic inflammation and social cognition difficulties, internalising problems, or externalising problems.

CONCLUSION

Our findings suggest that part of the effect of social communication difficulties in childhood on externalising problems in adolescence was mediated by lower morning cortisol. Hence, our study indicates that the hypoactivity of the hypothalamic-pituitary-adrenal (HPA) axis may be one of the physiological mechanisms linking some social cognition deficits to externalising problems.

Depressive Symptoms Account for Loss of Positive Attention Bias in ADHD Patients: An Eye-Tracking Study

OBJECTIVES

Depression and ADHD often co-occur and are both characterized by altered attentional processing. Differences and overlap in the profile of attention to emotional information may help explain the co-occurence. We examined negative attention bias in ADHD as neurocognitive marker for comorbid depression.

METHODS

Patients with depression (n = 63), ADHD (n = 43), ADHD and depression (n = 25), and non-psychiatric controls (n = 68) were compared on attention allocation toward emotional faces. The following eye-tracking indices were used: gaze duration, number of revisits, and location and duration of first fixation.

RESULTS

Controls revisited the happy faces more than the other facial expressions. Both the depression and the comorbid group showed significantly less revisits of the happy faces compared to the ADHD and the control group. Interestingly, after controlling for depressive symptoms, the groups no longer differed on the number of revisits.

CONCLUSION

ADHD patients show a relative positive attention bias, while negative attention bias in ADHD likely indicates (sub)clinical comorbid depression.

The effects of early life stress on impulsivity

Elevated impulsivity is a symptom shared by various psychiatric disorders such as substance use disorder, bipolar disorder, and attention-deficit/hyperactivity disorder. However, impulsivity is not a unitary construct and impulsive behaviors fall into two subcategories: impulsive action and impulsive choice. Impulsive choice refers to the tendency to prefer immediate, small rewards over delayed, large rewards, whereas impulsive action involves difficulty inhibiting rash, premature, or mistimed behaviors. These behaviors are mediated by the mesocorticolimbic dopamine (DA) system, which consists of projections from the ventral tegmental area to the nucleus accumbens and prefrontal cortex. Early life stress (ELS) alters both impulsive choice and impulsive action in rodents. ELS also changes DA receptor expression, transmission, and activity within the mesocorticolimbic system. This review integrates the dopamine, impulsivity, and ELS literature to provide evidence that ELS alters impulsivity via inducing changes in the mesocorticolimbic DA system. Understanding how ELS affects brain circuits associated with impulsivity can help advance treatments aimed towards reducing impulsivity symptoms in a variety of psychiatric disorders.

Childhood Trajectories of Hyperactivity/Inattention Symptoms and Diurnal Cortisol in Middle Adolescence: Results from a UK Birth Cohort

OBJECTIVE

Children with attention-deficit/hyperactivity disorder (ADHD) show hypoactivity of the hypothalamic-pituitary-adrenal (HPA) axis. Whether the association between hyperactivity/inattention symptoms with HPA axis dysfunction holds in the general child population too is not clear.

METHOD

We assessed associations between longitudinal trajectories of hyperactivity/inattention symptoms during ages 4 to 13 years and basal cortisol profiles at age 15 in a British general population cohort.

RESULTS

Adolescents with persistently high levels of hyperactivity/inattention symptoms since childhood showed lower total morning cortisol and a smaller diurnal decline, even after adjusting for confounders. No associations were found between any of the symptom trajectories and cortisol awakening response, diurnal slope or daily output of cortisol.

CONCLUSION

This study provides evidence for hypocortisolism among adolescents with chronic hyperactivity/inattention symptoms in the general population.

Challenging the negative learning bias hypothesis of depression: reversal learning in a naturalistic psychiatric sample

BACKGROUND

Classic theories posit that depression is driven by a negative learning bias. Most studies supporting this proposition used small and selected samples, excluding patients with comorbidities. However, comorbidity between psychiatric disorders occurs in up to 70% of the population. Therefore, the generalizability of the negative bias hypothesis to a naturalistic psychiatric sample as well as the specificity of the bias to depression, remain unclear. In the present study, we tested the negative learning bias hypothesis in a large naturalistic sample of psychiatric patients, including depression, anxiety, addiction, attention-deficit/hyperactivity disorder, and/or autism. First, we assessed whether the negative bias hypothesis of depression generalized to a heterogeneous (and hence more naturalistic) depression sample compared with controls. Second, we assessed whether negative bias extends to other psychiatric disorders. Third, we adopted a dimensional approach, by using symptom severity as a way to assess associations across the sample.

METHODS

We administered a probabilistic reversal learning task to 217 patients and 81 healthy controls. According to the negative bias hypothesis, participants with depression should exhibit enhanced learning and flexibility based on punishment v. reward. We combined analyses of traditional measures with more sensitive computational modeling.

RESULTS

In contrast to previous findings, this sample of depressed patients with psychiatric comorbidities did not show a negative learning bias.

CONCLUSIONS

These results speak against the generalizability of the negative learning bias hypothesis to depressed patients with comorbidities. This study highlights the importance of investigating unselected samples of psychiatric patients, which represent the vast majority of the psychiatric population.

Inflammation, Anxiety, and Stress in Attention-Deficit/Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent and serious neurodevelopmental disorder characterized by symptoms of inattention and/or hyperactivity/impulsivity. Chronic and childhood stress is involved in ADHD development, and ADHD is highly comorbid with anxiety. Similarly, inflammatory diseases and a pro-inflammatory state have been associated with ADHD. However, while several works have studied the relationship between peripheral inflammation and stress in affective disorders such as depression or bipolar disorder, fewer have explored this association in ADHD. In this narrative review we synthetize evidence showing an interplay between stress, anxiety, and immune dysregulation in ADHD, and we discuss the implications of a potential disrupted neuroendocrine stress response in ADHD. Moreover, we highlight confounding factors and limitations of existing studies on this topic and critically debate multidirectional hypotheses that either suggest inflammation, stress, or anxiety as a cause in ADHD pathophysiology or inflammation as a consequence of this disease. Untangling these relationships will have diagnostic, therapeutic and prognostic implications for ADHD patients.

Mapping relationships between ADHD genetic liability, stressful life events, and ADHD symptoms in healthy adults

Attention-deficit/hyperactivity disorder (ADHD) symptoms are continuously distributed in the general population, where both genetic and environmental factors play roles. Stressful life events (SLEs) have been associated with ADHD diagnosis, but the relationship between ADHD genetic liability, SLEs, and ADHD symptoms in healthy individuals is less clear. Using a sample of 1,531 healthy adults (average age 26.9 years; 55.8% female), we investigated relationships between ADHD polygenic risk scores (ADHD-PRSs), SLEs, and ADHD symptoms in a general population sample. Confirming earlier findings in an overlapping sample, all SLE-measures assessed (lifetime SLEs, recent SLEs, and childhood trauma (CT)) were significantly correlated with total ADHD, inattention (IA), and hyperactivity-impulsivity (HI) scores (r² range = .08-.15; all p < .005). ADHD-PRSs was associated with HI (R²_best-fit  = .37%), lifetime SLEs (R²_best-fit  = .56%), and CT (R²_best-fit  = .40%). Mediation analyses showed that lifetime SLEs partially mediated the association between ADHD-PRSs and HI (indirect effect: β = 68.6, bias corrected accelerated 95% confident interval (BCa95%CI) [11.9, 131.0], p = .016, proportion mediated (P_M ) =19.5%), with strongest effects contributed by CT (β = 34.4, BCa95%CI [0.4, 76.5], p = .040, P_M  = 9.8%). On the other hand, HI partially mediated the association between the ADHD-PRSs and lifetime SLEs (β = 42.9, BCa95%CI [7.3, 83.9], p = .014, P_M  = 18.8%). Our study observed a complex relationship of genetic and environmental risk factors contributing to ADHD symptoms in the healthy adult population.

A single episode of stress during adolescence impairs short-term memory and increases risk behaviour in an animal model of attention-deficit/hyperactivity disorder

Adolescence is a period of increased sensitivity to stress and vulnerability to the manifestation of psychiatric disorders, such as attention-deficit/hyperactivity disorder (ADHD). Nevertheless, the relationship between stress during adolescence and ADHD is still unclear. Knowing that stress can have long-term consequences, the aim of this study was to evaluate the impact of a single episode of restraint stress during adolescence on locomotion, risk behaviour and short-term memory in adult spontaneously hypertensive rats (SHR), a validated animal model of ADHD. A single episode of stress during adolescence increased risk behaviour and impaired short-term recognition memory, but did not alter locomotion in adult SHR. These findings show that stress during adolescence, even acute, may lead to long-term behavioural consequences in an animal model of ADHD.

Negative memory bias as a transdiagnostic cognitive marker for depression symptom severity

BACKGROUND

Negative memory bias is a strong risk factor for the development and maintenance of depression. Recent evidence also found negative memory bias in other mental disorders. Here, we aim to: 1) assess the presence and strength of negative memory bias in a range of (comorbid) mental disorders, 2) investigate which disorder-specific symptoms are associated with negative memory bias, and 3) test whether negative memory bias might be a transdiagnostic mechanism.

METHODS

Negative memory bias was measured in patients with at least one diagnosis of a stress-related disorder (n = 86), a neurodevelopmental disorder (n = 53), or both (n = 68), and 51 controls. Depression, anxiety, attention-deficit/hyperactivity disorder, and autism spectrum disorder symptom severity was assessed using questionnaires. Groups were compared on negative memory bias and the associations between negative memory bias and symptom severity were made using linear regression models.

RESULTS

All patient groups showed stronger negative memory bias than the controls. Negative memory bias was individually associated with all symptom severity indices, but when added into a single model, only the association with depressive symptom severity remained. This persisted after controlling for diagnostic group.

LIMITATIONS

Due to the cross-sectional sectional study design, we could only look at the associations between negative memory bias and disorder-specific symptoms and not at the direction of the effects.

CONCLUSIONS

Negative memory bias is characteristic of a depressotypic processing style and present in different mental disorders. It might play a mechanistic role in the development of (subclinical) co-occurrence between mental disorders.

Early Life Trauma Has Lifelong Consequences for Sleep And Behavior

Sleep quality varies widely across individuals, especially during normal aging, with impaired sleep contributing to deficits in cognition and emotional regulation. Sleep can also be impacted by a variety of adverse events, including childhood adversity. Here we examined how early life adverse events impacted later life sleep structure and physiology using an animal model to test the relationship between early life adversity and sleep quality across the life span. Rat pups were exposed to an Adversity-Scarcity model from postnatal day 8–12, where insufficient bedding for nest building induces maternal maltreatment of pups. Polysomnography and sleep physiology were assessed in weaning, early adult and older adults. Early life adversity induced age-dependent disruptions in sleep and behavior, including lifelong spindle decreases and later life NREM sleep fragmentation. Given the importance of sleep in cognitive and emotional functions, these results highlight an important factor driving variation in sleep, cognition and emotion throughout the lifespan that suggest age-appropriate and trauma informed treatment of sleep problems.

Influence of early adversity on cortisol reactivity, SLC6A4 methylation and externalizing behavior in children of alcoholics

BACKGROUND

Children of parents with alcoholism face considerable stress, and often have externalizing behaviors. Early adversity is known to affect DNA methylation and the functioning of the HPA axis. We investigated the association of early adversity with cortisol reactivity, 5HTTLPR genotype, site specific DNA methylation in the SLC6A4 gene and externalizing behavior in children of alcoholics (COA), and a matched sample of control children.

METHODS

We examined children of alcoholics (N = 50) and age matched control children (N = 50) for exposure to early adversity (both prenatal and postnatal), assessed their salivary cortisol reactivity and evaluated their levels of emotional and behavioral difficulty in terms of externalizing and internalizing behavior. Site-specific DNA methylation at a previously characterized SLC6A4 region was determined in salivary DNA using pyrosequencing. The 5HTTLPR region of the SLC6A4 gene was also genotyped.

RESULTS

COA had significantly higher experience of early adversity than control children. Cortisol reactivity was reduced in COA, and negatively correlated with early adversity. Both early adversity and cortisol reactivity correlated with externalizing behavior. SLC6A4 methylation was higher in COA, and correlated with early adversity. SLC6A4 genotype did not show association with any of the variables.

CONCLUSION

Our study provides further evidence that early adversity is associated with blunted cortisol reactivity, increased site-specific CpG DNA methylation at the SLC6A4 gene, and high externalizing behavior.

Relationship between attention-deficit hyperactivity disorder symptoms and problem gambling: A mediation analysis of influential factors among 7,403 individuals from the UK

BACKGROUND AND AIMS

Our goal was to examine the association between attention-deficit hyperactivity disorder (ADHD) symptoms and gambling problems, and to identify potential mediating factors of this association.

METHODS

This study used cross-sectional, community-based data from 7,403 people aged ≥16 years who participated in the Adult Psychiatric Morbidity Survey 2007. ADHD symptoms were assessed using the Adult ADHD Self-Report Scale (ASRS) Screener. Problem gambling was assessed using a questionnaire based on the 10 DSM-IV diagnostic criteria for pathological gambling. Respondents were classified as having no problem, at-risk, or problem gambling. Logistic regression and mediation analyses were conducted to analyze the association between ADHD symptoms (i.e., ASRS score ≥14) and problem gambling and the role of several variables in this association.

RESULTS

The prevalence of at-risk (5.3% vs. 2.4%) and problem gambling (2.4% vs. 0.6%) was higher in individuals with ADHD symptoms than in those without ADHD symptoms. ADHD symptoms were significantly associated with both at-risk (OR = 2.15; 95% CI = 1.22-3.79) and problem gambling (OR = 3.57; 95% CI = 1.53-8.31) when adjusted for age, sex, and ethnicity. Common mental disorders (CMDs; i.e., depression and anxiety disorders) (mediated percentage = 22.4%), borderline personality disorder (BPD) traits (22.1%), stressful life events (13.2%), stress at work or home (12.6%), alcohol dependence (11.8%), and impulsivity (11.2%) were significant mediators in the ADHD-gambling association.

DISCUSSION AND CONCLUSIONS

Overall, ADHD symptoms were positively associated with problem gambling. CMDs, BPD traits, and stressful life events were important mediators in this relationship.