People with intellectual disabilities experience higher rates of mental disorders, contributing to restrictive practices and premature mortality. Prevalence data are essential to understanding the patterns of disease, and for the development of tailored interventions.

To systematically examine the burden and pattern of mental disorders in people with intellectual disabilities across the lifespan.

We searched six databases (inception to 17 October 2024), and conducted a manual search up to 15 December 2024, for systematic reviews on the prevalence of mental disorders in people with intellectual disabilities with or without neurodevelopmental conditions. We conducted a narrative synthesis of prevalence rates, including those stratified by intellectual disability level, sex, age and autism, where available, and compared these with published prevalence rates in people without intellectual disabilities (International Prospective Register of Systematic Reviews, no. CRD42024610611).

We included 26 systematic reviews: 7 meta-analyses and 19 narrative reviews. Compared with the general population, the prevalence of schizophrenia (3.55–4.80%), anxiety (5.4–5.5%) and obsessive–compulsive disorders (2.4%) appeared higher, whereas that of mood (6–7%), personality and post-traumatic stress disorders appeared lower. Study quality was moderate to critically low. For syndromic intellectual disabilities we noted high anxiety rates in fragile-X, Williams and 22q11.2 deletion syndromes, and in those with co-occurring autism. We found gaps on dementia, bipolar, substance use and eating disorders, and limited data stratified by intellectual disability level, sex and age.

This umbrella review confirms the high prevalence of mental disorders among people with intellectual disabilities, and highlights limited evidence for several conditions and population subgroups, including for minoritised ethnic groups. Standardised, high-quality epidemiological research is needed to shape clinical care and public mental health policy.

Adults with intellectual disabilities who display behaviours that challenge (BtC) are more prone to poor health.

This study seeks to evidence the long-term health outcomes for those who display BtC.

We conducted a longitudinal cohort study of adults with intellectual disabilities aged ≥18 years in England, using data from the Clinical Practice Research Datalink Aurum (January 2003 to December 2023) linked to Hospital Episode Statistics and Office for National Statistics. Main outcome measures were annual health checks, general practitioner referrals, emergency visits, out-patient attendance, in-patient admissions and mortality.

Among 83 166 adults with intellectual disabilities (mean age 38.6 years), 18.5% had a record of BtC, with similar sociodemographic distributions to those without BtC, but higher rates of physical and mental health comorbidities and uptake of annual health checks. A total of 72.5% of participants with BtC were receiving psychotropic medication(s). Adults with BtC had higher rates of mental health out-patient attendance (odds ratio: 1.42, 95% CI 1.33–1.52) and in-patient admissions (incidence rate ratio (IRR): 1.19, 95% CI 1.09–1.29), but consistently lower rates of physical health out-patient attendance (IRR = 0.81, 95% CI 0.78–0.84) and in-patient admissions (IRR = 0.77, 95% CI 0.74–0.79), after adjusting for demographic and clinical characteristics. BtC were not associated with mortality after adjustment for comorbidities (hazard ratio: 0.97, 95% CI 0.93–1.00).

This longitudinal study not only corroborated the markedly elevated burden of physical and mental health comorbidities among individuals displaying BtC, but also indicated that repeated efforts to improve health outcomes have yielded minimal measurable benefit over time. The apparent absence of progress is likely underpinned by a combination of insufficiently effective or poorly tailored interventions and wider systemic constraints that limit the capacity of services to respond to the complex needs of this population.

Mental health difficulties affect the well-being of doctors and compromise the delivery of healthcare. However, large-scale data on doctors’ mental health needs are limited.

Describe patterns of self-referrals for mental health support among doctors in England and explore associations with demographic factors, speciality, neurodevelopmental and mental health indicators.

Observational study using data from doctors who self-referred for mental health difficulties to a national service in England over a 4-year period. Logistic regression was used to explore associations between speciality and mental health indicators.

Of the 16 815 doctors who self-referred during the study period, 80% were under the age of 49 and 70.6% were female with the two largest ethnicities being 65.1% White and 22.7% Asian. Women were more likely to report higher scores for depression (odds ratio 0.90, 95% CI = 0.84 to 0.97), anxiety (odds ratio 0.78, 95% CI = 0.72 to 0.84) and psychological distress (odds ratio 0.78, 95% CI = 0.70 to 0.87), but males were more likely to screen positive for attention-deficit hyperactivity disorder (ADHD) symptoms. Doctors in general practice accounted for 46.3% of referrals. Compared with them, doctors in most other specialities had higher odds of elevated mental health scores across all measures, including ADHD.

The findings highlight a significant mental health burden among self-referring doctors, particularly for females and doctors in non-general practice specialities. Tailored and easily accessible support strategies that account for both demographic and professional contexts are essential to address the diverse mental health needs of the medical workforce.

Behaviours that challenge are highly prevalent in children with an intellectual disability and can be detrimental to their quality of life and opportunities.

The systematic review aimed to investigate the effectiveness of current interventions in reducing behaviours that challenge in children with an intellectual disability (≤18 years-old).

We searched five databases (PsychINFO, MEDLINE, Embase, Web of Science and CINAHL) on 26 April 2022 and 1 July 2024, and identified 18 randomised controlled trials (1443 participants) eligible for inclusion since 2014 – 11 investigated non-pharmacological and 9 investigated pharmacological interventions. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool.

Non-pharmacological interventions (mostly psychosocial) were significantly effective (Hedges’ g = −0.20; 95% CI [−0.35, −0.05]), whereas pharmacological interventions (including a wide range of drug classes and substances) were not (g = 0.03; 95% CI [−0.17, 0.24]). Studies using the Child Behaviour Checklist reported significant reductions (g = −0.18; 95% CI [−0.34, −0.02]), whereas studies using the Aberrant Behaviour Checklist did not (g = 0.04; 95% CI [−0.16, 0.25]). A random-effects meta-analysis indicated no overall significant reduction in behaviours that challenge (g = −0.12; 95% CI [−0.24, 0.00]).

It is important to note that most studies included were conducted in Western countries and had small sample sizes, and findings may be due to the outcome measures used. Findings support current recommendations that non-pharmacological interventions should be first-line treatment for behaviours that challenge in this population. Evidence highlighted the need for better quality, adequately powered randomised controlled trials.

Adults with intellectual disability experience increased rates of mental health disorders and adverse mental health outcomes.

Explore childhood risk factors associated with adverse mental health outcomes during adulthood as defined by high cost of care, use of psychotropic medication without a severe mental illness and psychiatric hospital admissions.

Data on 137 adults with intellectual disability were collected through an intellectual disability community service in an inner London borough. Childhood modifiable and non-modifiable risk factors were extracted from records to map onto variables identified as potential risk factors. Logistic and linear regression models were employed to analyse their associations with adverse outcomes.

We showed that the co-occurrence of intellectual disability with autism spectrum disorder and/or attention-deficit hyperactivity disorder (ADHD) were associated with psychotropic medication use and high-cost care packages. However, when challenging behaviour during childhood was added, ADHD and autism spectrum disorder were no longer significant and challenging behaviour better explained medication prescribing and higher cost care. In addition, the severity of intellectual disability was associated with higher cost care packages. Ethnicity (Black and mixed) also predicted higher cost of care.

Challenging behaviour during childhood emerged as a critical variable affecting outcomes in young adulthood and mediated the association between adult adverse mental health outcomes and co-occurring neurodevelopmental conditions, that is, ADHD and autism. These findings emphasise the need for effective early intervention strategies to address challenging behaviour during childhood. Such interventions for challenging behaviour will need to take into consideration autism and ADHD.

This survey of 66 specialist mental health services aimed to provide an up-to-date description of pathways of care and interventions available to children with an intellectual disability referred for behaviours that challenge or with suspected mental health problems.

Overall, 24% of services made contact with a family at referral stage, whereas 29% contacted families at least once during the waiting list phase. Only two in ten services offered any therapeutic input during the referral or waiting list stages. During the active caseload phase, services offered mostly psychoeducation (52–59%), followed by applied behaviour analytic approaches for behaviours that challenge (52%) and cognitive–behavioural therapy (41%). Thirty-six per cent of services had not offered any packaged or named intervention in the past 12 months.

With increasing waiting times for specialist mental health support, services need to consider increasing the amount of contact and therapeutic input on offer throughout all stages of a child's journey with the service.

NHS England recommends the commissioning of intensive support teams (ISTs) to provide effective support to people with intellectual disability (ID) when in crisis. However, there is a paucity of evidence regarding how these services should be organised. This exploratory secondary analysis of data from the IST-ID study aimed to investigate IST characteristics that relate to clinical outcomes. The primary outcome was mean change in the total score on the Aberrant Behavior Checklist and its subscales.

A measure of mental illness severity was the only variable associated with our primary outcome of reduction in challenging behaviour. Accommodation type, affective status and gender were associated with the subdomains of irritability, hyperactivity and lethargy in unadjusted and adjusted analyses.

Our findings indicate that variation in clinical outcomes is influenced by individual rather than organisational factors. Further research on the theoretical fidelity of the IST-ID model is needed.

People with borderline intellectual functioning (BIF) encounter greater social adversities than the general population and have an increased prevalence of mental illness. However, little is known about the socio-demographic characteristics and mental health of parents with BIF.

A secondary data analysis of the Adult Psychiatric Morbidity Survey 2014 was conducted. Logistic regression models were fitted to compare differences in socio-demographic, mental health and service-use characteristics between parents and non-parents with and without BIF, and to investigate if the relationship between parent status and mental health outcomes was modified by BIF status, sex, and employment.

Data from 6872 participants was analyzed; 69.1% were parents. BIF parents had higher odds of common mental disorder, severe mental illness, post-traumatic stress disorder, self-harm/suicide and were more likely to see their General Practitioner (GP) and to receive mental health treatment than non-BIF parents. BIF parents did not have a higher prevalence of mental health problems than BIF non-parents. Being a parent, after adjusting for BIF status and other confounders, was associated with increased odds of having a common mental disorder, visits to see a GP and treatment for mental health. Female parents had higher odds of treatment for mental health problems.

Being a parent is associated with elevated rates of common mental disorders. There is a higher burden of mental health problems and service use in people with BIF. A greater provision of specialist support services including ascertainment is indicated for this group.

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.

Intellectual Developmental Disorder (IDD) is diagnosed with cognitive and adaptive behaviour evaluations. There is increasing evidence of a high prevalence of psychiatric disorders comorbid with IDD. The relationship between specific cognitive dysfunctions and psychiatric vulnerability may provide the basis for a paradigm shift from “intellectually below average IQ” to “neuropsychological characterization”.

1) reassessing an IDD sample in cognitive profile and psychiatric comorbidities 2) investigating the correlations between specific cognitive dysfunctions and specific psychiatric diagnoses in IDD.

120 individuals with IDD from 3 Italian facilities were consecutively evaluated, one group with mild IDD, using WAIS-IV or Leiter-3, TMT, Stroop and TOL tests, after which a professional caregiver did individual interviews (Vineland Adaptive Behavior Scale-II, SPAIDD-G, and STA-DI) to evaluate the patient adaptive behaviour, psychiatric comorbidities and presence of ASD. The second group (more severe IDD), was evaluated only with professional caregiver assessment tools.

90 males and 30 females, mean age 57 years, institutionalized for a mean period of 36.44 years. 52% had no education, 19% a middle school diploma. IDD diagnoses: borderline 3%, mild 16%, moderate 11%, moderate-severe 4%, severe 59%, profound 0%.11% comorbid ASD diagnosis, 29% with ASD after diagnostic re-assessment (STA-DI). 89% physical comorbidities, 58% psychiatric comorbidities, 56% psychoses (Fig. 1). Psychiatric comorbidities re-assessment (SPAIDD-G) identified a significant number of disorders (Fig. 2), despite the medical records showed a low prevalence of psychiatric diagnoses. The consistent quantity of psychotropic drugs prescribed in the sample, possibly reflects the real prevalence of psychopathology. Pearson correlations (p<0.05). WAIS-IV and SPAIDD-G (N=29): Verbal Comprehension Index correlates with anxiety disorder and impulse control disorder; Perceptual Reasoning Index correlates with nutrition/feeding disorder; Processing Speed Index correlates with nutrition/feeding disorder and sexual disorder; IQ correlates with ASD, nutrition/feeding, anxiety, sexual disorders. Leiter-3 and SPAIDD-G (N=14): Form Completion and non-verbal IQ correlate with OCD negatively.

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In conclusion, the SPAIDD-G evaluations revealed a greater prevalence of psychopathology than reported in the medical records. Using psychopathological screening tools can improve the diagnostic process in residential facilities for IDD cases. Pearson’s analyses revealed the need to further investigate the correlation between cognitive dysfunctions and psychopathological vulnerability, studying intelligence as a multi-component model and identifying specific behavioural and cognitive phenotypes in IDD cases.

None Declared

Intensive support teams (ISTs) are recommended for individuals with intellectual disabilities who display behaviours that challenge. However, there is currently little evidence about the clinical and cost-effectiveness of IST models operating in England.

To investigate the clinical and cost-effectiveness of IST models.

We carried out a cohort study to evaluate the clinical and cost-effectiveness of two previously identified IST models (independent and enhanced) in England. Adult participants (n = 226) from 21 ISTs (ten independent and 11 enhanced) were enrolled. The primary outcome was change in challenging behaviour between baseline and 9 months as measured by the Aberrant Behaviour Checklist-Community version 2.

We found no statistically significant differences between models for the primary outcome (adjusted β = 4.27; 95% CI −6.34 to 14.87; P = 0.430) or any secondary outcomes. Quality-adjusted life-years (0.0158; 95% CI: −0.0088 to 0.0508) and costs (£3409.95; 95% CI −£9957.92 to £4039.89) of the two models were comparable.

The study provides evidence that both models were associated with clinical improvement for similar costs at follow-up. We recommend that the choice of service model should rest with local services. Further research should investigate the critical components of IST care to inform the development of fidelity criteria, and policy makers should consider whether roll out of such teams should be mandated.