ADHD causes significant distress and functional impairment in multiple domains of daily life. Therefore, diagnosis and treatment are important to improve the quality of life of people. The pharmacotherapy for ADHD is well established but needs systematic evaluation in Intellectual Disability (ID) populations.
This paper reviews the ADHD pharmacological treatment in people with ID using the PRISMA guidance for scoping reviews to help identify the nature and strength of evidence.
In the last 20 years, seven randomized controlled trials have evaluated pharmacotherapies for ADHD in people with ID; five looking at methylphenidate. Generally, studies were underpowered; all but two had less than 25 participants. Of the two larger trials one was single blinded and therefore open to bias. Only two used a parallel-group method, the remainder were mostly short crossover trials; not ideal when measuring behavioral and psychological parameters which are long standing. The remaining evidence is made up of observational studies. Methylphenidate and atomoxetine, particularly at higher doses, have shown clear benefits in people with ID. Most people with ID tolerated ADHD medications well. Benefits were seen in behavioral and/or cognitive domains. The evidence base is limited, though promising, for dexamfetamine, clonidine, and guanfacine.