Association between adverse home environments and symptoms in drug-naive children with attention-deficit/hyperactivity disorder

To the editor:

Adverse home environments (AHE), characterised by family conflict, parental separation or dysfunctional parenting, are linked to negative mental health outcomes in children and adults.^{1 2} AHE disproportionately affect children with neurodevelopmental disorders such as attention-deficit/hyperactivity disorder (ADHD), which is characterised by inattention, hyperactivity/impulsivity and functional impairments.³ Apart from core symptoms, including inattention and hyperactivity, disruptive behaviour disorders (DBD), such as oppositional defiant disorder (ODD) and conduct disorder (CD), may be associated with AHE. Conduct problems are risk factors for ODD. And CD has become a main concern for childhood mental health.⁴ Despite evidence linking AHE to behavioural problems, few studies have examined their association with ADHD symptoms, particularly in untreated populations.⁵ This study investigates the relationship between AHE and ADHD core symptoms (inattention, hyperactivity/impulsivity, opposition/defiance) while adjusting for diagnostic and intervention confounders.

Participants

The participants were recruited from the paediatric outpatient department of the Shanghai Mental Health Centre, a public psychiatric hospital affiliated with the Shanghai Jiao Tong University School of Medicine, Shanghai, China. The data were collected between November 2016 and December 2021.

Eligible children were diagnosed with ADHD by a psychiatrist through psychiatric assessments and did not have any psychiatric comorbidities according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. To eliminate confounding factors of culture, only children of Han Chinese ethnicity were enrolled. All eligible children were newly diagnosed with ADHD and did not receive any intervention prior to data collection. Children with psychotic disorders, bipolar disorder or an intelligence quotient score less than 70 (measured using the Wechsler Intelligence Scale for Children, Fifth Edition) were excluded. In this study, we obtained data from 343 children with ADHD.

Adverse home environments (AHE)

The absence of parents was considered an AHE for children.¹ An unsatisfactory family atmosphere, assessed subjectively through parental and parent–child relationship dynamics, has been found to be associated with worse mental outcomes in children and adolescents.^{6 7} An ideal family atmosphere is characterised as enjoyable, supportive and warm. However, there is no systematic method for measuring family atmosphere. The family atmosphere is measured using the family atmosphere dimension of the Questionnaire of Systemic Family Dynamics, rated on a 5-point Likert scale.⁸ The Chinese version of the family atmosphere dimension exhibited a Cronbach’s alpha of 0.87. In this study, we defined AHE as a non-nuclear/extended family structure (eg, single-parent households) or a family atmosphere score of ≤3 (on a scale of 1–5, with higher scores indicating a more enjoyable, helpful and warm family atmosphere).¹

ADHD symptoms

ADHD symptoms were assessed via the Swanson, Nolan, and Pelham Rating Scale, Version IV Scale (SNAP-IV) subsets: inattention (score≥13), hyperactivity/impulsivity (≥13) and opposition/defiance (≥8).⁹

Behavioural/functional outcomes

Behavioural/functional outcomes were assessed using Conners Parent Symptom Questionnaire (PSQ)¹⁰ and Weiss Functional Impairment Rating Scale (WFIRS-P).¹¹

Statistical analysis

Associations between AHE and symptoms were analysed using Fisher’s exact tests, logistic regression, receiver operating characteristic curves¹² and partial least squares (PLS)¹³ regression. All statistical tests were two-sided, and the significance level was set at p=0.05.

Sample characteristics

This study included 343 children newly diagnosed with ADHD (266 (77.6%) boys; mean (standard deviation) age: 8.88 (2.19) years). A smaller proportion of children with ADHD who exhibited non-clinical levels of core symptoms had AHE compared with those with clinically significant core symptoms (9.4% (9 of 96) vs 48.6% (120 of 247) (online supplemental figure S1). Children with ADHD and AHE were more likely to exhibit clinically significant core symptoms than those without AHE.

AHE and ADHD symptoms

Statistically significant differences were also found in SNAP-IV (opposition/defiance and inattention), PSQ (conduct problems, psychosomatic problems and anxiety) and WFIRS-P (family, school, life skills, social activities and risky activities) items between children with ADHD with or without AHE (onlinesupplemental figure S2 table S1). Among core symptoms, hyperactivity/impulsivity was not associated with increased odds of AHE. Children with ADHD and AHE were more likely to exhibit opposition/defiance and inattention symptoms compared with those without AHE and had a higher prevalence of associating conduct problems (odds ratio (OR)=1.628; 95% confidence interval (CI) 1.392 to 1.903) and functional impairments in various domains, including family life (OR=1.379; 95% CI 1.052 to 1.808), school life (OR=1.352; 95% CI 1.069 to 1.709) and life skills (OR=1.392; 95% CI 1.089 to 1.799) (figure 1 and online supplemental table S2).

Figure 1. ROC curves of efficient factors for core symptoms of attention deficit/hyperactivity disorder. (a) ROC curve for identifying the relationship between conduct problems (p=0.003, group without vs with AHE) and opposition/defiance symptoms (p=0.010, group without vs with AHE): AUC=0.851, ****p<0.0001. (b) ROC curve for assessing the association between life skills (p=0.009, group without vs with AHE), school (***p<0.001, group without vs with AHE) and family (****p<0.0001, group without vs with AHE) factors with inattention symptoms (p=0.041, group without vs with AHE). Combined effect of these three factors: AUC=0.754, ****p<0.0001. AHE, adverse home environments; AUC, area under the curve; ROC, receiver operating characteristic.

Behavioural/functional correlations

Among children with ADHD and AHE, opposition/defiance was linked to conduct problems (PLS coefficient=2.067), and inattention was associated with school impairments (PLS coefficient=1.090). No significant AHE-hyperactivity/impulsivity relationships were found. See more details in onlinesupplemental figure S3, table S3 S4.

AHE were prevalent among children with untreated ADHD and independently associated with inattention and opposition/defiance symptoms.^{14 15} Unlike hyperactivity/impulsivity, these symptoms correlated with functional impairments in family, school and daily living. The lack of association between AHE and hyperactivity contrasts with prior studies involving treated cohorts, suggesting early intervention of AHE may mitigate inattention but not hyperactivity.

In this study, the evaluation of AHE was based on family type and atmosphere. Parental removal and placement in foster or out-of-home care have been associated with adverse outcomes in adulthood.¹ An undesirable family atmosphere is characterised as being less warm and stable. The evaluation of family atmosphere relies on the subjective feelings of family members, lacking systematic methods for measurement. Thus, we used a scoring system to quantify the degree of unfavourable family atmospheres. To our knowledge, this study is the first to explicitly examine the association between ADHD symptoms and AHE after adjusting for diagnostic and intervention confounders. Previous intervention studies in this field primarily focused on genetics and other environmental factors, including premature birth, low birth weight, alcohol and nicotine exposure during pregnancy, advanced parental age at childbirth and family history of psychiatric conditions. Few studies have examined the negative impact of AHE on children with ADHD,^{5 15} and those that did included only children who were already diagnosed and receiving interventions, such as medication and non-pharmacological treatments.

In this cross-sectional study, 72.0% of children with ADHD exhibited clinically significant core symptoms, with approximately half of them exposed to AHE. Among those with non-clinical core symptoms, only 9.4% had AHE. Furthermore, children with ADHD and AHE were more likely to have comorbidity of DBD than those without AHE. Inattention was more common among children with ADHD and AHE, and its association with functional impairment of family, school and life skills remained evident, even after adjusting for diagnostic and intervention confounders. Contrary to our expectations, we did not observe any differences in hyperactivity/impulsivity symptoms between children with ADHD with and without AHE. While this aspect is outside the primary focus of our current investigation, we investigated the key components related to hyperactivity/impulsivity. Our analysis suggests that improvements in family functioning do not significantly mitigate hyperactivity/impulsivity. Although external behaviours, including hyperactivity/impulsivity and DBD, are commonly included in ADHD symptom evaluation, they may not be appropriate for children with ADHD and AHE.

Our study significantly augments the current understanding of ADHD in children with AHE by elucidating the presence of characteristic symptoms, such as DBD and inattention, which are concomitantly associated with functional impairments in family, school and life skills.

Strengths

The principal strengths of this study are the comprehensive evaluation of ADHD symptoms and the utilisation of data collected from children initially diagnosed with ADHD but who had not yet received any intervention.

Limitations

First, while parental information regarding education level and mental disorder history was gathered, the lack of data on family income restricted the generalisability of the findings. Second, the study population comprised only children of Han Chinese ethnicity from urban areas and thus lacked national representation. Third, the results relied on observational data rather than randomised clinical trials, and the potential influence of residual confounders on outcomes remains uncertain. Fourth, given the lack of validated family atmosphere measures, a median threshold of three categorisations was operationalised. Finally, the relatively small sample size of 247 participants may have been insufficient to detect significant differences.

Given these limitations, crucial questions regarding the potential effect of AHE on children with ADHD warrant further exploration, particularly for predicting mental health outcomes. Future large-scale and more comprehensive investigations are warranted to thoroughly examine the association between AHE and ADHD symptoms.

Conclusion

This cross-sectional study conducted on children newly diagnosed with ADHD by clinical psychiatrists revealed that after adjusting for potential diagnostic and intervention confounders, the association between AHE and ADHD symptoms persisted. Our findings indicate that children with ADHD and AHE are more prone to DBD comorbidities and, in the initial stages, often display minimal relevant functional impairment. Notably, children with ADHD and AHE exhibited significantly more inattention symptoms than those without AHE, suggesting a distinct ADHD subtype. This inattention among children with ADHD and AHE may correlate with functional impairments in family, school and life skills but may not necessarily contribute to behavioural disorders. These patterns suggest that AHE modulates core symptoms of ADHD and specifically contributes to behavioural disorders and functional impairment in children.

Biography

Chengchao Yu obtained her master’s degree from the Faculty of Medicine at the University of Liège, Belgium in 2022. She is currently working as a resident doctor in the medical department of Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine in China. Her main research interests include emotional and behavioural disorders, depressive disorders, and substance use disorders (SUD). Notably, Dr Yu has demonstrated expertise in adolescent mental health, publishing impactful research examining the global disease burden attributable to SUD among adolescent populations. Her scholarly work employs multidimensional analysis of epidemiological trends, risk factors, and intervention strategies, contributing valuable insights to both clinical practice and public health policy formulation.