Attention deficit hyperactivity disorder (ADHD) is increasingly diagnosed in adults. People with intellectual disability have higher rates of ADHD yet there is little evidence on the presentation and pharmacological treatment of ADHD in this population or how this differs from the general population.

Retrospective cohort study using data from electronic health records. Adults with intellectual disability newly diagnosed with ADHD between 2007 and 2022 were matched to adults with ADHD without intellectual disability and their clinical features and treatments were compared.

A total of 159 adults with ADHD and intellectual disability and 648 adults with ADHD without intellectual disability formed the dataset. Adults with intellectual disability had higher rates of psychiatric co-morbidity and spent more time under mental health services than those without intellectual disability. They were more likely to have recorded agitation, aggression, hostility, and mood instability, and less likely to have poor concentration recorded in the 12 months prior to the diagnosis of ADHD. Following diagnosis, people with intellectual disability were significantly less likely to be prescribed any medication for ADHD than controls without intellectual disability (adjusted odds ratio 0.60, 95% confidence interval 0.38–0.91), and were less likely to be prescribed stimulants (27.7% v 46.0%, p < 0.001).

The presence of behaviors that challenge in adults with intellectual disability may indicate co-occurring ADHD. Further work to define the safety and efficacy of medication for ADHD in adults with intellectual disability is needed to understand differences in prescription rates and to avoid inequities in care outcomes.

Down syndrome is the most common genetic cause of intellectual disability and Alzheimer's disease. In the general population, common mental disorders (CMDs), including anxiety, depression and obsessive–compulsive disorder, are linked to cognitive decline and higher risk for dementia. It is not known how CMDs affect longer-term cognitive outcomes in Down syndrome, and there is often diagnostic uncertainty in older people with Down syndrome and psychiatric comorbidity.

To study the influence of CMDs on cognitive ability and whether they are related longitudinally to development of clinical signs of Alzheimer's disease in Down syndrome.

We followed 115 individuals with Down syndrome, 27 of whom were diagnosed with a CMD, over approximately 3 years. Changes in cognitive and behavioural outcomes between baseline and follow-up assessment were analysed, with comparisons made between those with and without a comorbid CMD. Age, gender, apolipoprotein E status and level of intellectual disability were included as covariates.

No significant association between presence of a CMD and poorer performance on cognitive tasks or informant-rated decline over time was observed (P > 0.05).

Our results suggest that a diagnosis of a CMD does not have a significant negative effect on long-term cognitive or behavioural outcomes in individuals with Down syndrome. In individuals with stable or treated CMD, subsequent cognitive decline is likely indicative of Alzheimer's disease rather than a consequence of mental disorder.

People with intellectual disability often experience aggressive challenging behaviour and mental health issues. It can be difficult to identify those who are at higher risk of adverse clinical outcomes when in clinical care.

To characterise potential subgroups in adults with intellectual disability referred to mental health services in those presenting with aggressive behaviour or common mental disorders (CMDs).

There were 836 adults (≥18 years) with intellectual disability and a record of aggressive challenging behaviour, and 205 patients with intellectual disability and CMDs, who were seen in specialist mental health services over a 5-year period. Cluster analysis was used to define patient characteristics associated with clinical outcome.

Distinct patient groups with differentiated profiles were observed in people with intellectual disability displaying aggressive challenging behaviour, and in those presenting with CMDs. Characteristics of the aggressive behaviour group who experienced adverse outcomes included being <30 years old, being male, more mentions of aggression and agitation in their clinical record, a diagnosis of pervasive developmental disorder and prescription of psychotropic medication. Characteristics of the CMD cluster that experienced adverse clinical outcomes were being older, being a White male, having a mild intellectual disability and physical health concerns.

People with intellectual disability who experience adverse clinical outcomes can be identified with a cluster analysis approach of common features, but differ by clinical presentation. This could be used not only to stratify this clinically heterogeneous population in terms of response to interventions, but also improve precision in the development of tailored interventions.

Aggressive challenging behavior in people with intellectual disability is a frequent reason for referral to secondary care services and is associated with direct harm, social exclusion, and criminal sanctions. Understanding the factors underlying aggressive challenging behavior and predictors of adverse clinical outcome is important in providing services and developing effective interventions.

This was a retrospective total-population cohort study using electronic records linked with Hospital Episode Statistics data. Participants were adults with intellectual disability accessing secondary services at a large mental healthcare provider in London, United Kingdom, between 2014 and 2018. An adverse outcome was defined as at least one of the following: admission to a mental health hospital, Mental Health Act assessment, contact with a psychiatric crisis team or attendance at an emergency department.

There were 1,515 patient episodes related to 1,225 individuals, of which 1,019 episodes were reported as displaying aggressive challenging behavior. Increased episode length, being younger, psychotropic medication use, pervasive developmental disorder (PDD), more mentions of mood instability, agitation, and irritability, more contact with mental health professionals, and more mentions of social and/or home care package in-episode were all associated with increased odds of medium-high levels of aggression. Risk factors for an adverse clinical outcome in those who exhibited aggression included increased episode length, personality disorder, common mental disorder (CMD), more mentions of agitation in-episode, and contact with mental health professionals. PDD predicted better outcome.

Routinely collected data confirm aggressive challenging behavior as a common concern in adults with intellectual disability who are referred for specialist support and highlight factors likely to signal an adverse outcome. Treatment targets may include optimizing management of CMDs and agitation.

Social cognition is frequently impaired following an acquired brain injury (ABI) but often overlooked in clinical assessments. There are few validated and appropriate measures of social cognitive abilities for ABI patients. The current study examined the validity of the Edinburgh Social Cognition Test (ESCoT, Baksh et al., 2018) in measuring social cognition following an ABI.

Forty-one patients with ABI were recruited from a rehabilitation service and completed measures of general ability, executive functions and social cognition (Faux Pas; FP, Reading the Mind in the Eyes; RME, Social Norms Questionnaire; SNQ and the ESCoT). Forty-one controls matched on age, sex and years of education also performed the RME, SNQ and ESCoT.

A diagnosis of ABI was significantly associated with poorer performance on all ESCoT measures and RME while adjusting for age, sex and years of education. In ABI patients, the ESCoT showed good internal consistency with its subcomponents and performance correlated with the other measures of social cognition demonstrating convergent validity. Better Trail Making Test performance predicted better ESCoT total, RME and SNQ scores. Higher TOPF IQ was associated with higher RME scores, while higher WAIS-IV working memory predicted better FP performance.

The ESCoT is a brief, valid and internally consistent assessment tool able to detect social cognition deficits in neurological patients. Given the prevalence of social cognition deficits in ABI and the marked impact these can have on an individual’s recovery, this assessment can be a helpful addition to a comprehensive neuropsychological assessment.

Current measures of social cognition have shown inconsistent findings regarding the effects of executive function (EF) abilities on social cognitive performance in older adults. The psychometric properties of the different social cognition tests may underlie the disproportional overlap with EF abilities. Our aim was to examine the relationship between social cognition and EF abilities using the Edinburgh Social Cognition Test (ESCoT; Baksh, R.A., Abrahams, S., Auyeung, B., & MacPherson, S.E. (2018). The Edinburgh Social Cognition Test (ESCoT): Examining the effects of age on a new measure of theory of mind and social norm understanding. PloS One, 13(4), e0195818.), a test assessing four different aspects of social cognition: cognitive theory of mind (ToM), affective ToM, interpersonal understanding of social norms, and intrapersonal understanding of social norms.

We administered the ESCoT, EF measures of inhibition, set shifting, updating, and a measure of processing speed to 30 younger and 31 older adults. We also administered the Visual Perspective Taking task (VPT) as a ToM test thought to be reliant on EF abilities.

Better performance on cognitive ToM was significantly associated with younger age and slower processing speed. Better performance on affective ToM and ESCoT total score was associated with being younger and female. Better performance on interpersonal understanding of social norms was associated with being younger. EF abilities did not predict performance on any subtest of the ESCoT. In contrast, on the VPT, the relationship between age group and performance was fully or partially mediated by processing speed and updating.

These findings show that the ESCoT is a valuable measure of different aspects of social cognition and, unlike many established tests of social cognition, performance is not predicted by EF abilities.