Attention-deficit hyperactivity disorder in people with intellectual disability: statistical approach to developing a bespoke screening tool

Abstract

Background Attention-deficit hyperactivity disorder (ADHD) is common among people with intellectual disability. Diagnosing ADHD in this clinically and cognitively complex and diverse group is difficult, given the overlapping psychiatric and behavioural presentations. Underdiagnoses and misdiagnoses leading to irrational polypharmacy and worse health and social outcomes are common. Diagnostic interviews exist, but are cumbersome and not in regular clinical use. Aims We aimed to develop a screening tool to help identify people with intellectual disability and ADHD. Method A prospective cross-sectional study, using STROBE guidance, invited all carers of people with intellectual disability aged 18–50 years open to the review of the psychiatric team in a single UK intellectual disability service (catchment population: 150 000). A ten-item questionnaire based on the DSM-V ADHD criteria was circulated. All respondents’ baseline clinical characteristics were recorded, and the DIVA-5-ID was administered blinded to the individual questionnaire result. Fisher exact and multiple logistic regressions were conducted to identify relevant questionnaire items and the combinations that afforded best sensitivity and specificity for predicting ADHD. Results Of 78 people invited, 39 responded (26 men, 13 women), of whom 30 had moderate-to-profound intellectual disability and 38 had associated comorbidities and on were medication, including 22 on psychotropics. Thirty-six screened positive for ADHD, and 24 were diagnosed (16 men, eight women). Analysis showed two positive responses on three specific questions to have 88% sensitivity and 87% specificity, and be the best predictor of ADHD. Conclusions The three-question screening is an important development for identifying ADHD in people with intellectual disability. It needs larger-scale replication to generate generalisable results.

Assessing and managing attention-deficit hyperactivity disorder in people with intellectual disability

“…There are no assessment tools validated in larger populations to screen for ADHD in people with intellectual disability. A recent study in a small group showed that the following three questions have high positive and negative predictive values, sensitivity and specificity (Sawhney 2021): Does the person find it hard to sit in one place for long? Does the person pace up and down most of the time? Is the person easily distractible by busy environments? …”

“…Functional impairment can affect academic, social or occupational domains but the most common functional impairment in people with intellectual disability is challenging behaviour affecting many domains of life. A recent study of adults with intellectual disability and ADHD reported that almost 70% presented with challenging behaviour (Perera 2021). Therefore, a careful analysis of functional impairment is important to explore underlying ADHD symptoms.…”

“…There are no assessment tools validated in larger populations to screen for ADHD in people with intellectual disability. A recent study in a small group showed that the following three questions have high positive and negative predictive values, sensitivity and specificity (Sawhney 2021):…”

“…Studies have shown that nearly 70% of people with intellectual disability and ADHD also meet diagnostic criteria for autism spectrum disorder (ASD) (Perera 2021). Recent evidence points in the direction of genetic links between ADHD and the wider group of neurodevelopmental disorders (Rietz 2020).…”

“…Those have shown that diagnosis and treatment is associated with significant improvements in quality of life. Even though there are no large studies evaluating the benefits of treatment in people with intellectual disability, evidence overwhelmingly supports it (Perera 2018(Perera , 2021Faraone 2021).…”