An increasing body of evidence suggests that childhood maltreatment, including physical abuse, sexual abuse and neglect, may be associated with an increased risk of ADHD (Fuller-Thomson, Lewis 2015; Linares et al. 2010; Ouyang et al. 2008). However, studies examining the role of maltreatment in the early course of the disorder have been limited by a lack of robust longitudinal evidence. This study aimed to address these limitations by using a three-wave longitudinal design to investigate the impact of early maltreatment on ADHD.
The study recruited 2491 Latino male and female children (aged 5–13 years) from the Boricua Youth Study, who were interviewed with their caretaker at one of two study sites (South Bronx in New York, NY, USA, n=1138; Puerto Rico, South America, n=1353). Data were collected in three annual waves between 2000 and 2004; interviews were performed at the first wave (baseline, T1) when participants were aged between 5–13 years, with follow-up interviews occurring annually for 2 consecutive years (T2, T3).
Using logistic regression mixed models, a number of measures were assessed for their impact on ADHD:
- Neglect, physical abuse and emotional abuse: assessed using The Parental Discipline Practices Scale (children’s report only), which includes eight items in a 4-point scale that evaluates parental use of six forms of non-physical discipline and two forms of physical punishment.
- Sexual abuse: assessed using the sexual victimisation measure from Finkelhor and Dziuba-Leatherman, which includes six screener yes/no questions regarding sexual abuse and assault.*
- ADHD: diagnosed using the parent/caretaker’s report on the Diagnostic Interview Schedule for Children IV (DISC-IV), on each wave.† Participants with ADHD were classified as “persistent” or “in remission” based on the frequency of positive diagnosis on each wave.‡ Children without diagnosis on the three waves were classified as non-ADHD cases.
- Demographic characteristics and covariates: data collected included age, sex, medication use in the previous year, indicators of family socioeconomic status and parental education, parental psychopathology, as well as the presence of post-traumatic stress disorder (PTSD) and conduct disorder (CD).
Of 2480 children (male: 1279 [50.9%]; female: 1201 [49.1%]) interviewed in the first wave of the study, 2176 completed the third wave of the study (retention rate of 88.0%). A summary of the study results is presented below:
Concurrent associations between early maltreatment, foster placement and ADHD
- In the baseline model, emotional abuse (odds ratio [OR] 2.52, 95% confidence interval [CI] 1.50–4.51; p < 0.001), physical abuse (OR 1.71, 95% CI 1.01–2.89; p = 0.04) and foster placement (OR 4.81, 95% CI 1.93–11.98; p = 0.001) were significantly associated with ADHD diagnosis.
- Following adjustment for demographic characteristics and covariates, emotional abuse (OR 2.41, 95% CI 1.45–4.03; p = 0.001) and foster placement (OR 5.11, 95% CI 1.96–13.36; p = 0.001) remained significant with robust associations with ADHD.
- After adjusting for all maltreatment simultaneously, emotional abuse (OR 2.46, 95% CI 1.49–4.07; p = 0.001) and foster placement (OR 5.47, 95% CI 2.01–14.92; p = 0.001) remained significantly associated with ADHD.
Differential associations by sex
- The weighted prevalence of ADHD on wave 1 (T2) was 10.2% and 4.8% for boys and girls, respectively.
- In boys, emotional abuse was significantly associated with ADHD across waves (baseline model: OR 2.69, 95% CI 1.48–4.88, p = 0.001; model adjusted for demographic characteristics and covariates: OR 2.59, 95% CI 1.41–4.76, p = 0.002).
- This association remained significant following adjustment for the presence of PTSD (OR 2.74, 95% CI 1.46–5.13; p = 0.002) and CD (OR 2.75, 95% CI 1.48–5.10; p = 0.001).
- In girls, physical abuse was significantly associated with ADHD across waves (baseline model: OR 3.22, 95% CI 1.63–6.36, p = 0.001; model adjusted for demographic characteristics and covariates: OR 3.01, 95% CI 1.47–6.18, p = 0.003).
- Again, this association remained significant following adjustment for the presence of PTSD (OR 2.93, 95% CI 1.43–6.00; p = 0.003) or CD (OR 2.62, 95% CI 1.33–5.18; p = 0.006).
Prospective associations between maltreatment and ADHD
- Only physical abuse was significantly associated with ADHD in prospective models of ADHD across waves (model adjusted for demographic characteristics and covariates: OR 2.01, 95% CI 1.09–3.71; model adjusted for all comorbid disorders: OR 2.05, 95% CI 1.10–3.81; both p < 0.05).
Association between maltreatment exposure and ADHD persistence
- For each additional wave that included a physical or emotional abuse event, there was a significantly increased risk of having ADHD, and of having persistent ADHD symptoms (OR 1.40, 95% CI 1.08–1.81; p = 0.01).
This study was limited by a number of key factors. For example, as datasets were combined from two different sites, the reported estimates may have been subject to unexplained variance. Furthermore, it remains unclear as to whether the findings from this study are generalisable to children beyond Puerto Ricans. The criteria for ADHD were also based on the Diagnostic and Statistical Manual of Mental Disorders – 4th Edition (DSM-IV) and did not include alternative (e.g., teacher) reports as part of assessment. Finally, maltreatment may have been subject to recall bias, as it was self-reported by children.
The authors concluded that children who are exposed to maltreatment and adversity are at an increased risk of developing ADHD; physical abuse was more closely associated with ADHD in girls, emotional abuse was more closely associated with ADHD in boys, and exposure to maltreatment across time increased the risk of persistent ADHD. These findings highlight the importance of identifying families at risk for maltreatment and establishing early intervention and parent training.
Read more about the link between childhood maltreatment and ADHD here
*Sexual incidences included serious non-contact incidents (perpetrator touching a child in a sexual way, but without contact to private parts) and contact incidents
†An ADHD diagnosis was determined when symptom criteria and one DISC-IV diagnosis-specific impairment and age-of-onset criteria were met
ǂChildren were classified as “persistent” if they had more than one positive ADHD classification and their diagnostic status at the endpoint (T3) was positive. Children were classified as “in remission” if they had only one positive classification and did not meet ADHD criteria at the endpoint (T3)
Fuller-Thomson E, Lewis DA. The relationship between early adversities and attention-deficit/hyperactivity disorder. Child Abuse Negl 2015; 47: 94-101.
González RA, Vélez-Pastrana M, McCrory E, et al. Evidence of concurrent and prospective associations between early maltreatment and ADHD through childhood and adolescence. Soc Psychiatry Psychiatr Epidemiol 2019; Epub ahead of print.
Linares LO, Li M, Shrout PE, et al. The course of inattention and hyperactivity/impulsivity symptoms after foster placement. Paediatrics 2010; 125: e489-e498.
Ouyang L, Fang X, Mercy J, et al. Attention-deficit/hyperactivity disorder symptoms and child maltreatment: a population-based study. J Pediatr 2008; 153: 851-856.