Successful diagnosis of attention deficit hyperactivity disorder in later life of an adult with intellectual disability: A case report

Background Diagnosing and managing attention deficit hyperactivity disorder in adults with intellectual disabilities is currently largely based on findings from assessment and treatment in children or adults without intellectual disabilities. Current evidence suggests that individuals with intellectual disabilities are more likely to have attention deficit hyperactivity disorder compared to those without intellectual disabilities, but more research is needed. There is increasing knowledge of diagnosing and treating attention deficit hyperactivity disorder in people with intellectual disabilities with published guidance on delivering care based on good evidence. More is needed so that clinicians do not have to depend on the evidence from those who do not have intellectual disabilities. Method To write this report, we reviewed a female in her 50s with mild intellectual disability who has been known to general and specialist intellectual disability mental health services for at least 20 years over many episodes of care. We assessed her clinically and using the Diagnostic Interview for attention deficit hyperactivity disorder in Adults with intellectual disabilities to make a diagnosis of attention deficit hyperactivity disorder. We call her Mary, which is not her real name. Findings Mary has had many diagnoses however, we found that her neurodevelopmental disorders of attention deficit hyperactivity disorder and we believe, autism were missed which led to a complex presentation of behavioural and mental symptoms; and diagnostic and management challenges. Mary was receiving combinations of medications known as antipsychotics, antidepressants, hypnotics and mood stabilisers to high doses. She was able to stop them all successfully over 12-18 months before being diagnosed with attention deficit hyperactivity disorder. Once diagnosed with attention deficit hyperactivity disorder, Mary rapidly responded to a long acting stimulant as recommended by the National Institute for Health and Care Excellence and this has significantly improved her quality of life. Conclusion Attention deficit hyperactivity disorder in people with intellectual disabilities is often missed and inadequately managed, despite having highly effective and specific treatment strategies. Making the diagnoses of attention deficit hyperactivity disorder and intellectual disabilities is important as individuals with both together have worse outcomes. Therefore, effective treatment of attention deficit hyperactivity disorder in individuals with intellectual disabilities is critical.