Background: ADHD, when assessed using DSM IV criteria, is the most prevalent behavioral disorder (5%)in the United Kingdom (UK). Evidence is emerging that a percentage of children presenting with complex traumarelated symptoms may be misdiagnosed as having ADHD. However, the estimated prevalence is considerably lower(1.5%) when ICD-10 criteria are used to assess HKD. It is currently not known whether risk for misdiagnosis is an issue when the narrower ICD-10 criteria are used. This study aimed to systematically investigate these issues in order to investigate if: (1) significant associations between maltreatment exposures and ADHD symptom severity and HKD diagnosis were evident; (2) the percentage of trauma exposed HKD diagnosed cases whose parents reported an etiological link between trauma exposures and (a) symptom onset and (b) persistence of symptoms; (3) thepercentage of trauma exposed HKD cases who were being treated with Methylphenidate or Dexamphetamine. Methods: Data from the B-CAMHS epidemiological survey were analyzed (N=7997; male n=4111; femalen=3886). A Multiple Indicators Multiple Causes (MIMIC) approach was utilized. The effects of physical abuse (PA), sexual abuse (SA) and domestic violence (DV) on the structure of a four-factor model consisting of teacher and parent“hyperactivity” and “inattentiveness” were investigated. Binary logistic regression analyses were estimated to examine links between maltreatment and HKD diagnoses. Population attributable fractions (PAFs) were calculated to estimate the percentage of cases where exposures to maltreatment were directly implicated. Results: Significant associations between maltreatment exposures and the ADHD factors indicated that exposures significantly affected the manifestation of ADHD symptoms. Significant associations between HKD diagnoses and exposures to PA (OR=3.84, 95% CI=1.72-8.59) and DV (OR=3.46, 95% CI=1.98-6.05) were found. A total of 109 cases of HKD were diagnosed by the clinicians, of these a total of 26 cases (30%) were trauma exposed. Of these 26 cases, 45% of parents reported an etiological link between trauma exposure and current symptoms. Overall, 37.5% of physically abused and 15.8% of DV exposed HKD cases were taking stimulant based medication to treat their HKD symptoms. Conclusions: The increased likelihood of a diagnosis of ADHD/HKD among maltreated children may reflect the emotional and behavioral sequel of maltreatment. Children presenting with ADHD/HKD symptomatology should be screened for maltreatment exposures before diagnosis is concerned.