ADHD and risk for subsequent adverse childhood experiences: understanding the cycle of adversity

Adverse childhood experiences exacerbate peripheral symptoms of autism spectrum disorder in adults

AIM

Adverse childhood experiences are potentially traumatic events with long-lasting effects on the health and well-being of patients with autism spectrum disorder (ASD). It is important to clarify which types of long-lasting autism-related symptoms are influenced by childhood experiences to design future intervention studies. However, few studies have examined the association between childhood experiences and autistic symptoms in large samples of adults with ASD and individuals with typical development (TD). In this study, we evaluate the effects of adverse childhood experiences on multiple ASD phenotypes among both individuals with ASD and those with TD.

METHOD

We combined questionnaire evaluations; Childhood Abuse and Trauma Scale, the Japanese version of the Autism-Spectrum Quotient, Conners' Adult ADHD Rating Scale, the Japanese version of the Impact of Event Scale-Revised, and the Japanese version of the Adolescent/Adult Sensory Profile.

RESULTS

Individuals with ASD and those with TD (n = 205 and 104, respectively) were included. There were significant correlations between the extent of adverse childhood experiences and severity of attention-deficit/hyperactivity disorder symptoms, posttraumatic stress disorder symptoms, and hypersensitivity in both participants with ASD and those with TD. By contrast, ASD core symptoms showed no significant correlation with adverse childhood experiences in either group. These results remained consistent after adjusting for age, sex, and the estimated intelligence quotient.

CONCLUSION

These findings suggest the need for a detailed disentanglement of ASD-related core and peripheral symptoms of adverse childhood experiences, which may help to appropriately set outcomes for future early interventions for the childhood experiences of individuals with ASD.

Development and validation of a nomogram prediction model for ADHD in children based on individual, family, and social factors

OBJECTIVES

A reliable, user-friendly, and multidimensional prediction tool can help to identify children at high risk for ADHD and facilitate early recognition and family management of ADHD. We aimed to develop and validate a risk nomogram for ADHD in children aged 3-17 years in the United States based on clinical manifestations and complex environments.

METHODS

A total of 141,356 cases were collected for the prediction model. Another 54,444 cases from a new data set were utilized for performing independent external validation. The LASSO regression was used to control possible variables. A final risk nomogram for ADHD was established based on logistic regression, and the discrimination and calibration of the established nomogram were evaluated by bootstrapping with 1000 resamples.

RESULTS

A final risk nomogram for ADHD was established based on 13 independent predictors, including behavioral problems, learning disabilities, age, intellectual disabilities, anxiety symptoms, gender, premature birth, maternal age at childbirth, parent-child interaction patterns, etc. The C-index of this model was 0.887 in the training set, and 0.862 in the validation set. Internal and external validation proved that the model was reliable.

CONCLUSIONS

A nomogram, a statistical prediction tool that assesses individualized ADHD risk for children is helpful for the early identification of children at high risk for ADHD and the construction of a conceptual model of society-family-school collaborative diagnosis, treatment, and management of ADHD.

Positive Childhood Experiences and the Indirect Relationship With Improved Emotion Regulation in Adults With ADHD Through Social Support

OBJECTIVE

To identify direct and indirect associations between PCEs and social support to emotion regulation outcomes in adults with ADHD.

METHOD

Adults with ADHD (n = 81) reported PCEs, current social support, and emotion regulation. Conditional effects modeling examined the direct and indirect relationships between PCEs and emotion dysregulation through social support.

RESULTS

Higher PCEs were indirectly related to improved emotion regulation through increased social support generally (β = -.70, 95% CI [-1.32, -0.17], and specifically through belonging (β = -.43, 95% CI [ -0.87, -0.05], self-esteem (β = -.61, 95% CI [-1.08, -0.27], and tangible social support (β = -.50, 95% CI [-1.07, -0.02].

CONCLUSIONS

PCEs may protect emotion regulation in adults with ADHD through social support, possibly through facilitating social connections, increasing access to social support, and sustaining emotion regulation strategies.

Potential Mechanisms Underlying Suicidality in Autistic People with Attention Deficit/Hyperactivity Disorder: Testing Hypotheses from the Interpersonal Theory of Suicide

Background

Autistic people with co-occurring attention deficit/hyperactivity disorder (ADHD) appear to be at heightened risk of suicide. To understand why, we explored two explanatory mechanisms from the interpersonal theory of suicide: first, that co-occurring ADHD might be associated with greater risk through greater thwarted belongingness and perceived burdensomeness and, secondly, that hyperactive/impulsive features might incur additional risk through their association with painful and provocative events, which are suggested to create "capability" for suicide.

Methods

Autistic adults (n = 314) completed an online survey including measures of thwarted belongingness, perceived burdensomeness, painful and provocative events, acquired capability for suicide, and ADHD features. Creating an overall index of likely ADHD, we examined associations between likely ADHD, suicide ideation, and lifetime suicide attempts through the parallel mediators of thwarted belongingness, perceived burdensomeness, anxiety, and depression. In several models, we then examined hyperactive, impulsive, and inattentive features as predictors of exposure to painful and provocative events and subsequent capability for suicide, and examined whether these two variables, sequentially or individually, mediated an association with lifetime suicide attempts.

Results

Likely ADHD was associated with past-year suicide ideation through greater depression and perceived burdensomeness, which also mediated its association with more suicide attempts. Hyperactive and impulsive features were associated with exposure to painful and provocative events and through this acquired suicide capability. Both features were associated with more numerous suicide attempts through these two mediators sequentially, and through exposure to painful and provocative events alone.

Conclusions

These data suggest that suicidality in autistic people with ADHD may be partially related to perceived burdensomeness and to acquired suicide capability after exposure to painful and provocative events. However, as we observed a pathway to suicidality associated with painful and provocative events alone, it is likely that there are also other explanatory mechanisms for the influence of traumatic events on suicide risk.

Adverse Childhood Experiences and ADHD Symptoms Among French College Students

To examine the relationship between adverse childhood experiences (ACEs) and Attention-deficit Hyperactivity Disorder (ADHD) among college students. We investigated the association between ACEs and ADHD symptoms among French college students enrolled in the i-Share cohort using multivariate logistic regression models. The sample comprised of 1062 participants with a mean age of 20.3 (SD = 2.3) of which 30.6% had no ACEs exposure, 29.6% had 1 ACE, 19.2% had 2 ACEs, and 20.6% had ≥ 3 ACEs. After controlling for potential confounders, every increase in ACE exposure heightened the risk of ADHD symptoms with the respective adjusted Odds Ratios and 95% confidence intervals: 1 ACE: 2.1 (0.7-6.3) / 2 ACEs: 4.5 (2.6-12.8)/ ≥ 3 ACEs: 5.2 (1.8-14.8). Estimates for ADHD symptoms were higher with sexual abuse, emotional and physical neglect, and bullying. Findings suggest that ACEs heighten the risk for developing ADHD symptoms among college students and bear important implications for prevention and clinical practice.

Is there evidence of a causal link between childhood maltreatment and attention deficit/hyperactivity disorder? A systematic review of prospective longitudinal studies using the Bradford-Hill criteria

Background

Studies report an elevated risk of maltreatment in children with attention deficit/hyperactivity disorder (ADHD), and elevated levels of ADHD in people who suffered childhood maltreatment (CM). However, the direction(s) of causality between CM and ADHD remain unclear-does ADHD create a context for CM, does CM cause ADHD, or both?

Objective

This study systematically reviews and qualitatively synthesizes the research evidence relating to this question using Bradford-Hill criteria for establishing causality-strength, temporality, dose-response and plausibility.

Methods

We conducted a systematic review, following PRISMA guidelines, of prospective longitudinal studies examining both CM and ADHD. We then used Bradford-Hill criteria to assess the quality of evidence for a causal link between CM and ADHD.

Results

All 11 included studies demonstrated an association between CM and ADHD. Seven included evidence for temporality: five suggesting that CM precedes ADHD in the lifespan; two suggesting ADHD precedes CM. Four studies demonstrated a dose response relationship in which greater CM exposure was associated with elevated risk of ADHD. Studies presented a range of plausible mechanisms, including CM causing ADHD through biological programming, versus ADHD causing CM through parental stress.

Conclusions

The high quality prospective longitudinal studies reviewed confirm the association between ADHD and CM, but present conflicting evidence about the direction of causality and mechanisms underpinning this association. To better understand the complex interplay between CM and ADHD, more studies using new research designs will be required that can partition effects by type of CM and account for bidirectional effects and other complexities.

The Paradoxical Clinical Course of Persons with Gambling Disorder and Comorbid Attention-Deficit/Hyperactivity Disorder (ADHD)

The co-occurrence of gambling disorder (GD) and attention-deficit/hyperactivity disorder (ADHD) has been widely reported. In this study, we aimed to investigate the social background, clinical characteristics, and clinical course of initial-visit GD patients with and without ADHD in a Japanese psychiatric hospital. We recruited 40 initial-visit GD patients and collected comprehensive information by self-report questionnaires, direct interviews, and medical records. 27.5% of the GD patients had comorbid ADHD. Compared to the GD patients without ADHD, those with ADHD had significantly higher comorbidity rates of autism spectrum disorder (ASD), lower rates of marriage, slightly less years of education and marginally lower employment rates. On the other hand, the GD patients with ADHD showed higher treatment retention rates and participation rates in the mutual support group. Despite presenting with disadvantageous characteristics, GD patients with ADHD exhibited a more favourable clinical course. Therefore, clinicians should be mindful of the possibility of ADHD comorbidity and the potential for better clinical outcomes among GD patients with ADHD.

Relationship between hair cortisol concentrations and cognitive functioning in adolescents with ADHD

Background: Our study aimed to explore whether the hair cortisol concentration (HCC), a measure of long-term cortisol output, is associated with poorer cognitive functioning in adolescents with attention deficit and hyperactivity disorder (ADHD). We further aimed to test the potential moderating effects of sex and childhood maltreatment.Methods: In this cross-sectional study, fifty-three adolescents with ADHD were studied. The ADHD Rating Scale (ADHD-RS) and Childhood Trauma Questionnaire (CTQ) were administered. Seven cognitive tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were administered, and two cognitive factors (attention and memory and executive functioning) were identified by confirmatory factor analysis. A 3-cm hair sample from the posterior vertex region of the head was obtained. HCCs were determined by a high-sensitivity enzyme immunoassay kit. Multiple linear regression analyses were used to explore the association between HCCs and either cognitive performance or ADHD severity while adjusting for sex, childhood maltreatment and the ADHD-RS total score.Results: Sex moderated the relationship between HCCs and attention/memory confirmatory factor analysis (CFA) scores, with better performance in boys with higher HCCs. HCCs were not associated with executive functioning or ADHD symptoms. Childhood maltreatment was associated with inattention symptoms in adolescents with ADHD.Conclusions: Our study suggests that HCCs are positively associated with attention and memory performance in adolescents with ADHD, with a moderating effect of sex (the relationship is strongest in boys).

Adult ADHD Positive Screening and Sibship, Birth Order and Academic Achievement: Implications for Epidemiologists and Physicians in the Kingdom of Saudi Arabia

Background

Attention deficit hyperactivity disorder (ADHD) among the youth and university students differs internationally. This study aims to assess the prevalence of ADHD positivity from a validated screening test among medical students across the Kingdom of Saudi Arabia (KSA) and its associated sociodemographic and family-related factors and the impact of ADHD on students' academic performance. Also, to highlight the implications of the current findings on epidemiologists and family physicians in the region.

Methods

This cross-sectional study utilised the Adult ADHD Self-Report Scale (ASRS) symptom checklist along with several questions on sociodemographic, siblings and personal academic achievement. Multivariable logistic regression models were performed to obtain the Odds Ratios (ORs) of risk of ADHD screening positivity and their 95% confidence intervals (CIs) against potential predictors.

Results

The overall prevalence of positively screened medical students was 38.86%. After adjustment, a statistically significant increased risk of ADHD positivity was observed for students who had one sibling (OR = 1.70, 95% CI = 1.09-2.64). Also, upon examination of birth order, a significant increased risk was observed for students who were firstborn (OR = 1.22, 95% CI = 1.02-1.47). With regard to academic achievement, both before and after adjustment, students who screened positive had a 14% increased risk of obtaining an F GPA (OR = 1.14, 95% CI = 0.99-1.30).

Conclusion

A considerable number of medical students are potentially positive for ADHD. Albeit not diagnostically confirmed - this indicates that a substantial number of people have displayed symptoms akin to ADHD, but were not clinically diagnosed. Research into ADHD in the region is still in its infancy, and epidemiologists would benefit from high-quality databases to address this condition. Also, primary care physicians should develop skills in detecting and managing ADHD in children at an earlier age to improve symptoms in adulthood.

Healthcare utilization and comorbidity shortly before suicide mortality in patients with attention-deficit/hyperactivity disorder: a nested case-control study

BACKGROUND

Few studies have analyzed healthcare utilization before suicide among individuals with attention-deficit/hyperactivity disorder (ADHD). This study examined the pattern of healthcare utilization and comorbidities shortly before death among patients with ADHD who died by suicide and compared these data with those of living controls. This study used Taiwan's National Health Insurance Research Database to identify patients with ADHD (N = 379,440) between January 1, 2001, and December 31, 2016. Subsequently, the researchers identified 159 suicide decedents by linking each patient with the National Mortality Database. By conducting a nested case-control study with risk-set sampling from the ADHD cohort, the researchers selected 20 age- and sex-matched controls (n = 3180) for each patient who died by suicide (cases). The researchers then applied conditional logistic regression to investigate differences in healthcare utilization as well as psychiatric and physical comorbidities between case patients and controls. Case patients had higher healthcare utilization within 3 months before suicide, particularly in the psychiatry, emergency, internal medicine, neurosurgery, and plastic surgery departments. These patients also had higher risks of psychiatric comorbidities, including schizophrenia, bipolar disorder, depressive disorder, and sleep disorder, as well as physical comorbidities such as hypertension and other forms of heart disease. Among patients with ADHD, suicide decedents had increased healthcare utilization and higher risks of specific psychiatric and physical comorbidities than living controls. Thus, for suicide prevention among individuals with ADHD, suicide risk must be detected early and comorbidities should be adequately managed.

Factors Influencing Long-Term Behavioral Intervention Outcomes in Preschool Children with Attention-Deficit Hyperactivity Disorder in Southeast China

Introduction

Previous studies have demonstrated the long-term effectiveness of behavioral interventions for attention-deficit hyperactivity disorder (ADHD) in preschool children. We continue to design a case‒control study to further investigate the factors influencing the long-term effect of behavioral intervention.

Methods

From May 2020 to August 2021, children who were newly diagnosed with ADHD and not receiving any treatment received a one-year behavioral intervention. A total of 86 children completed the behavioral intervention and assessment.

Results

50 children (58.140%) were in the effective group, and 36 children (41.860%) were in the ineffective group. Attention retention time (OR=0.559, 0.322-0.969), Swanson, Nolan, and Pelham total score (OR=1.186, 1.024-1.374) at baseline, performance score for parents (OR=0.631, 0.463-0.859), and teacher coordination (OR=0.032, 0.002-0.413) were the influencing factors of behavioral intervention effects. The area under the receiver operating curve was 0.979 (p<0.001). The comprehensive nomogram model showed that the discrimination and mean absolute error were 0.979 and 0.023, respectively.

Discussion

During behavioral intervention, the implementation skills of parents should be evaluated in a timely manner. The behavioral intervention effect can be predicted based on a child's attention retention time at baseline, teacher involvement, behavioral scale score, and performance score for parents, which can guide clinicians in adjusting personalized treatment plans and provide a basis for clinical decision-making. The treatment of ADHD in preschool children requires a systematic framework that integrates family, school, and society.

Disentangling the Associations Between Attention Deficit Hyperactivity Disorder and Child Sexual Abuse: A Systematic Review

BACKGROUND

An association between child sexual abuse (CSA) and attention deficit hyperactivity disorder (ADHD) has been documented. However, the temporal relationship between these problems and the roles of trauma-related symptoms or other forms of maltreatment remain unclear. This review aims to synthesize available research on CSA and ADHD, assess the methodological quality of the available research, and recommend future areas of inquiry.

METHODS

Studies were searched in five databases including Medline and PsycINFO. Following a title and abstract screening, 151 full texts were reviewed and 28 were included. Inclusion criteria were sexual abuse occurred before 18 years old, published quantitative studies documenting at least a bivariate association between CSA and ADHD, and published in the past 5 years for dissertations/theses, in French or English. The methodological quality of studies was systematically assessed.

RESULTS

Most studies identified a significant association between CSA and ADHD; most studies conceptualized CSA as a precursor of ADHD, but only one study had a longitudinal design. The quality of the studies varied greatly with main limitations being the lack of (i) longitudinal designs, (ii) rigorous multimethod/ multiinformant assessments of CSA and ADHD, and (iii) control for two major confounders: trauma-related symptoms and other forms of child maltreatment.

DISCUSSION

Given the lack of longitudinal studies, the directionality of the association remains unclear. The confounding role of other maltreatment forms and trauma-related symptoms also remains mostly unaddressed. Rigorous studies are needed to untangle the association between CSA and ADHD.

Associations of neurodevelopmental risk factors with psychosis proneness: Findings from a non-clinical sample of young adults

Psychotic disorders often develop as the continuum of subclinical symptoms that include hallucination-like and delusion-like experiences, and are commonly referred to as psychotic-like experiences (PLEs). To date, a number of neurodevelopmental risk factors of psychosis have been detected, yet their mutual interplay remains unknown. Therefore, we aimed to investigate the additive association of childhood trauma history, reading disabilities and symptoms of attention-deficit/hyperactivity disorder (ADHD) with psychosis proneness. A total of 3000 young adults (58.3% females, aged 18-35 years) with a negative history of psychiatric treatment were recruited to the cross-sectional study through computer-assisted web interview. Self-reports were administered to measure childhood trauma history, ADHD symptoms and reading disabilities. Linear regression analyses revealed significant main associations of childhood trauma history and reading disabilities with higher levels of PLEs. There were no significant main associations of ADHD with the level of PLEs. However, the associations of all possible interactions between neurodevelopmental risk factors with the level of PLEs were significant. Our findings suggest that childhood trauma history and reading disabilities may additively increase a risk of psychosis. The present findings bring new implications for early intervention strategies in psychosis and posit the rationale of recording the accumulation of neurodevelopmental vulnerabilities in clinical practice.

Pharmacotherapy May Attenuate the Risk of Child Abuse in Attention-Deficit/Hyperactivity Disorder from the Real-World Evidence

Objective: Psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD), may serve as a risk factor for child abuse. Methods: This study aimed to evaluate the association between children and adolescents with ADHD diagnosis and the risk of child abuse. The effectiveness of a pharmacological intervention on reducing the risk of child abuse was also assessed. A nationwide, population-based, retrospective with a matched-cohort study design was used. Data were from the National Health Insurance Research Database of Taiwan over a 15-year period (2000-2015). Results: Increased risk of child abuse in the ADHD group was noticed and the adjusted hazard ratio (HR) was 1.797 (95% confidence interval [CI] = 1.245-2.388, p < 0.001). The Kaplan-Meier analysis showed a significantly higher cumulative incidence in the ADHD group over the 15-year period (Log-rank test p < 0.001). ADHD patients with other psychiatric comorbidities had a higher risk of child abuse. Pharmacological treatment of either methylphenidate or atomoxetine was associated with a reduced risk of child abuse. The total adjusted HR was 1.466 (95% CI = 1.077-1.883, p < 0.001) in medicine group compared with the controls. Conclusions: ADHD was associated with a subsequent risk of child abuse in Taiwan. Pharmacological treatment could reduce the risk of child abuse in ADHD patients.

Eye Movement Desensitization and Reprocessing (EMDR) as a Possible Evidence-Based Rehabilitation Treatment Option for a Patient with ADHD and History of Adverse Childhood Experiences: A Case Report Study

BACKGROUND

Children with Attention Deficit Hyperactivity Disorder (ADHD) having a history of adverse childhood experiences (ACEs) could be very difficult to treat with standard psychotherapeutic approaches. Some children diagnosed with ADHD may have Post-Traumatic Stress Disorder (PTSD) or have had experienced a significant traumatic event. Trauma and PTSD could exacerbate ADHD core symptoms and be a risk factor of poor outcome response.

OBJECTIVE

to report for the first time the history of a patient with ADHD and ACE successfully treated with an EMDR approach.

CONCLUSION

EMDR could be a promising treatment for ADHD children with a history of traumatic experiences in addition to pharmacological treatments.

Psychopathological Dissection of Bipolar Disorder and ADHD: Focussing on Racing Thoughts and Verbal Fluency

In the present study, we propose a review and a synthesis of the work of our group about the phenomenology and the cognitive mechanisms of racing thoughts in bipolar disorder (BD) and ADHD. Contrary to the mainstream idea according to which racing thoughts are pathognomonic of BD, our work suggests that racing thoughts are enhanced in ADHD compared to hypomanic episodes of BD, whereas in euthymic episodes of BD self-reported racing thoughts are similar to the rates reported by healthy controls. Using verbal fluency tasks, we found many similarities between bipolar and ADHD subjects with one clear difference: lexical search strategy in hypomania is based on phonemic similarities rather than semantic-relatedness. However, this distinction observed in this cognitive task is certainly difficult to grasp during a clinical interview aiming to differentiate mild hypomania from combined ADHD presentation. The main landmark to distinguish them remains the episodic nature of bipolar disorders as opposed to the lifelong presentation of ADHD symptoms, a dichotomous view that is not so clear-cut in clinical practice.

Understanding the association between adverse childhood experiences and subsequent attention deficit hyperactivity disorder: A systematic review and meta-analysis of observational studies

OBJECTIVES

Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in childhood, which may be related to adverse childhood experiences (ACEs). Our study aims to explore the association between ACEs and subsequent ADHD, and analyze the potential moderators.

METHODS

Literature search was conducted by a combined computer-assisted and manual method. Studies were included if they had reported the association between ACEs and subsequent ADHD. Overall estimates of odds ratios (ORs) were obtained using random-effects meta-analyses, meta-regressions and further stratified analyses were conducted to examine potential moderator variables.

RESULTS

Totals of 70 studies involving nearly 4 million participants from among 6,452 unique articles were included. In the primary analyses, ACEs were found to be associated with subsequent ADHD (OR = 1.68, 95% CI: 1.54-1.83), and the negative effects of different forms of ACEs for ADHD were nonequivalent. Such as lived in the stepfamily, been adopted or fostered, and experienced sexual abuse were more deleterious than others. It was found that individuals who had experienced multiple ACEs or who are female were more vulnerable to ADHD.

CONCLUSIONS

The findings provide critical evidence for understanding the association between ACEs and ADHD. ACEs could increase the susceptibility of ADHD, especially for individuals who ever experienced multiple ACEs and females.

Multiomic biological approaches to the study of child abuse and neglect

Childhood maltreatment, occurring in up to 20-30% of the population, remains far too common, and incorporates a range of active and passive factors, from abuse, to neglect, to the impacts of broader structural and systemic adversity. Despite the effects of childhood maltreatment and adversity on a wide range of adult physical and psychological negative outcomes, not all individuals respond similarly. Understanding the differential biological mechanisms contributing to risk vs. resilience in the face of developmental adversity is critical to improving preventions, treatments, and policy recommendations. This review begins by providing an overview of childhood abuse, neglect, maltreatment, threat, and toxic stress, and the effects of these forms of adversity on the developing body, brain, and behavior. It then examines examples from the current literature of genomic, epigenomic, transcriptomic, and proteomic discoveries and biomarkers that may help to understand risk and resilience in the aftermath of trauma, predictors of traumatic exposure risk, and potential targets for intervention and prevention. While the majority of genetic, epigenetic, and gene expression analyses to date have focused on targeted genes and hypotheses, large-scale consortia are now well-positioned to better understand interactions of environment and biology with much more statistical power. Ongoing and future work aimed at understanding the biology of childhood adversity and its effects will help to provide targets for intervention and prevention, as well as identify paths for how science, health care, and policy can combine efforts to protect and promote the psychological and physiological wellbeing of future generations.

Parental Age and the Risk of ADHD in Offspring: A Systematic Review and Meta-Analysis

Evidence has suggested that parental age at birth is a risk factor of offspring attention deficit/hyperactivity disorder (ADHD). We conducted a meta-analysis of observational studies investigating the association between parental age and offspring ADHD. We conducted a systematic search that followed the recommended guidelines for performing meta-analyses on PUBMED, EMBASE, and Web of Science up to 8 April 2021. We calculated pooled risk estimates from individual age with and without adjusting for possible confounding factors. Dose–response analysis for parental age and ADHD risk was performed. Eleven studies were selected in this meta-analysis, which included 111,101 cases and 4,417,148 participants. Compared with the reference points, the lowest parental age category was associated with an increased risk of ADHD in the offspring, with adjusted odds ratios (ORs) of 1.49 (95% confidence intervals (95%CI) 1.19–1.87) and 1.75 (95%CI 1.31–2.36) for the mother and father, respectively. The highest parental age was statistically insignificant, with adjusted ORs of 1.11 (95%CI 0.79–1.55) and 0.93 (95%CI 0.70–1.23) for mother and father separately. Dose–response analysis indicated a non-linear relationship of parental age with offspring ADHD, with the lowest ADHD risk at 31–35 years old. The results of this meta-analysis support an association between young parental age and the risk of ADHD. More high-quality studies are needed to establish whether the association with parental age is causal.