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Title: ADHD incidence, treatment and associated comorbidity in children and adolescents : an epidemiological study using electronic healthcare records
Author: Hire, Adrian James
ISNI:       0000 0004 6056 7711
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2017
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Background: ADHD is characterised by three core symptoms: hyperactivity, impulsivity and inattention. For those affected, ADHD can have a wide range of negative impacts. It has the potential to reduce academic performance, interfere with interpersonal relationships and is a purported risk factor for numerous mental and behavioural disorders, and accidental injury. However, questions remain regarding the epidemiology of ADHD in the UK. Aims: Phase 1: To describe the incidence and distribution of ADHD within the UK (2004-2013), and to examine if there was any association between ADHD incidence and socioeconomic deprivation. Phase 2: To assess what proportion of ADHD patients received a primary care prescription for a licensed ADHD medication, and to determine the average time between diagnosis and the start of treatment in primary care. Phase 3: To establish if selected comorbidities, and prescriptions for psychotropic drugs, are significantly more likely in patients with ADHD than matched comparators. Phase 4: To establish if accidental fractures are significantly more likely in patients with ADHD than matched comparators. Methods: The study used electronic healthcare records data. The study population comprised patients diagnosed with ADHD before the age of 19, between 1/1/2004 and 31/12/13. Patients with a diagnosis of ADHD, comorbidities of interest or who had received prescriptions for licensed ADHD medications/psychotropic drugs were identified by the presence of relevant codes in their medical records. Results: Phase 1: Between 2004 and 2013, the incidence of ADHD amongst under 19s in the UK was 11.67 (95% CI 11.45 – 11.90) cases per 10,000 person-years at risk. Most of those diagnosed with ADHD were male (n=8407; 82%). There appeared to be an association between increasing socioeconomic deprivation and ADHD incidence. Annual incidence rates remained relatively stable between 2004 and 2013, but were highest in the last two years studied. Phase 2: 57% of patients with a diagnosis of ADHD received a primary care prescription for a licensed ADHD medication during follow-up. In treated patients, the median interval between diagnosis and a first prescription for an ADHD medication was 84 days (IQR 21–258 days); methylphenidate was used first-line in 92% of treated patients. Phase 3: ADHD was associated with a significantly increased risk of comorbidity [RR 3.59 (95% CI 3.40 – 3.79)]. ADHD patients had significantly higher exposure to second generation antipsychotics [RR 29.48 (95% CI 23.25 – 37.40)], antidepressants and anxiolytics/hypnotics [RR 12.56 (95% CI 11.44 – 13.79)]. Phase 4: ADHD patients had a significantly higher risk of fracture relative to comparators [HR 1.17 (1.06 – 1.30)].Conclusion: ADHD incidence appears stable, but demographic factors can significantly influence an individual’s risk of being diagnosed with the disorder. Pharmaceutical treatment is far from universal in primary care, suggesting that GPs remain cautious about prescribing drugs for ADHD. Comorbid diagnoses are more likely among children with ADHD, and the increased use of psychotropics in this population suggests that these comorbidities are clinically-significant. ADHD patients’ higher risk of fracture lends support to the theory that impaired impulse control increases these patients’ risk of accidental injury.
Supervisor: Ashcroft, Darren ; Steinke, Douglas Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: ADHD