Incidence of unipolar and bipolar depression, and mania in adults with intellectual disabilities: prospective cohort study.

BACKGROUND: Incidence and determinants of affective disorders among adults with intellectual disabilities are unknown.AimsTo investigate affective disorder incidence, and determinants of unipolar depression, compared with general population reports. METHOD: Prospective cohort study measuring mental ill health of adults with mild to profound intellectual disabilities living within a defined community, over 2 years. RESULTS: There was 70% cohort retention (n = 651). Despite high mood stabiliser use (22.4%), 2-year incident mania at 1.1% is higher than the general population; 0.3% for first episode (standardised incident ratio (SIR) = 41.5, or 52.7 excluding Down syndrome). For any bipolar episode the SIR was 2.0 (or 2.5 excluding Down syndrome). Depression incidence at 7.2% is similar to the general population (SIR = 1.2), suggesting more enduring/undertreatment given the higher prevalence. Problem behaviours (odds ratio (OR) = 2.3) and life events (OR = 1.3) predict incident unipolar depression. CONCLUSIONS: Depression needs improved treatment. Mania has received remarkably little attention in this population, despite high prevalence and incidence (similar to schizophrenia), and given the importance of clinician awareness for accurate differential diagnosis from attention-deficit hyperactivity disorder and problem behaviours.Declaration of interestNone.

A cohort study of the prevalence of sleep problems in adults with intellectual disabilities.

Previous studies of the prevalence of sleep problems in adults with intellectual disabilities (ID) are affected by small, potentially biased samples and other limitations. This study aims to determine the prevalence and associations of sleep problems in the adult population with ID. The 4-week period prevalence of sleep problems was determined in a cross-sectional study of all adults with ID in a defined geographical area. Sleep problems were identified using the Psychiatric Assessment Scale for Adults with Developmental Disabilities (PAS-ADD) checklist and categorized as initial insomnia, early morning wakening and broken sleep. A fourth, composite, variable of significant sleep problem was also derived. Of the 1023 adults with ID who participated, 9.2% had experienced a significant sleep problem, during the 1-month period. Individuals with a significant sleep problem are more likely to have mental ill-health [odds ratio (OR) = 5.53, 95% confidence interval (CI) 3.52-8.69], problem behaviours (OR = 2.06, 95% CI: 1.25-3.41) and respiratory disease (OR = 2.03, 95% CI: 1.27-3.26). There is a positive association between visual impairment and initial insomnia (OR = 1.91, 95% CI: 1.21-3.04). Although a diagnosis of epilepsy is not associated with sleep problems, the finding that individuals taking antiepileptic medication are more likely to experience broken sleep (OR = 1.73, 95% CI: 1.13-2.66) suggests that medication side effects may impact on sleep of individuals with ID. The results suggest that there is a need to further examine the relationship between sleep problems and co-morbid health problems, which would inform the development of interventions, and trials of their efficacy.

The prevalence and incidence of mental ill-health in adults with autism and intellectual disabilities.

The prevalence, and incidence, of mental ill-health in adults with intellectual disabilities and autism were compared with the whole population with intellectual disabilities, and with controls, matched individually for age, gender, ability-level, and Down syndrome. Although the adults with autism had a higher point prevalence of problem behaviours compared with the whole adult population with intellectual disabilities, compared with individually matched controls there was no difference in prevalence, or incidence of either problem behaviours or other mental ill-health. Adults with autism who had problem behaviours were less likely to recover over a two-year period than were their matched controls. Apparent differences in rates of mental ill-health are accounted for by factors other than autism, including Down syndrome and ability level.

Prevalence of, and factors associated with, problem behaviors in adults with intellectual disabilities.

This study aimed to determine the prevalence of problem behaviors in adults with intellectual disabilities and to investigate which factors are independently associated with problem behaviors. A population-based cohort (n = 1023) had comprehensive individual assessments. Data were examined using multivariate logistic regression. The prevalence of problem behaviors was 22.5% (psychiatrists' opinion) or 18.7% (DC-LD criteria). Factors independently associated with problem behaviors were lower ability level, female gender, living in a congregate care setting or with paid carer support (rather than living with a family carer), having urinary incontinence; visual impairment, not having Down syndrome, and not having severe physical disabilities. Further studies focusing on the etiology, course, and treatment of problem behaviors are required.

Prevalence of physical conditions and multimorbidity in a cohort of adults with intellectual disabilities with and without Down syndrome: cross-sectional study.

OBJECTIVES: To investigate the prevalence of multimorbidity in adults with intellectual disabilities with and without Down syndrome. DESIGN: Large, population-based cross-sectional study. SETTING: The geographical area of one Health Board, Scotland. PARTICIPANTS: All adults (aged 16+ years) known to general practitioners to have intellectual disabilities and adults receiving services provided or paid by intellectual disabilities health or social work services. 1023/1562 potential participants took part (65.5%); 562 (54.9%) men and 461 (45.1%) women, aged 43.9 years (16-83 years). 186 had Down syndrome and 837 did not. MAIN OUTCOME MEASURES: The prevalence of International Statistical Classification of Diseases, 10th revision, physical health conditions and multimorbidity detected at a comprehensive health assessment. RESULTS: The mean number of physical health conditions/participant was 11.04, and 98.7% had multimorbidity. The most prevalent conditions are painful and/or disabling and, in some cases, life threatening. The five most prevalent were visual impairment, obesity, epilepsy, constipation and ataxic/gait disorders. The pattern of multimorbidity differs from that seen in the general population and is spread across the entire adult life course. The extent of multimorbidity in the adults with Down syndrome was similar to that of the adults without Down syndrome, while the prevalence of individual conditions differed. CONCLUSIONS: This robustly designed study with a large population found an extremely high prevalence of multimorbidity in adults with intellectual disabilities across the entire adult life course. This increases complexity of medical management that secondary healthcare services and medical education are not yet geared towards, as these tend to focus on single conditions. This is in addition to complexity due to limitations in communication and understanding. As the physical conditions within their multimorbidity also differ from that seen in the older general population, urgent attention is needed to develop the care pathways and guidelines that are required to inform and so improve their healthcare.

Problem behaviours and symptom dimensions of psychiatric disorders in adults with intellectual disabilities: An exploratory and confirmatory factor analysis.

BACKGROUND: The limited evidence on the relationship between problem behaviours and symptoms of psychiatric disorders experienced by adults with intellectual disabilities leads to conflict about diagnostic criteria and confused treatment. This study examined the relationship between problem behaviours and other psychopathology, and compared the predictive validity of dimensional and categorical models experienced by adults with intellectual disabilities. METHODS: Exploratory and confirmatory factor analyses appropriate for non-continuous data were used to derive, and validate, symptom dimensions using two clinical datasets (n=457; n=274). Categorical diagnoses were derived using DC-LD. Severity and 5-year longitudinal outcome was measured using a battery of instruments. RESULTS: Five factors/dimensions were identified and confirmed. Problem behaviours were included in an emotion dysregulation-problem behaviour dimension that was distinct from the depressive, anxiety, organic and psychosis dimensions. The dimensional model had better predictive validity than categorical diagnosis. CONCLUSIONS: International classification systems should not include problem behaviours as behavioural equivalents in diagnostic criteria for depression or other psychiatric disorders. Investigating the relevance of emotional regulation to psychopathology may provide an important pathway for development of improved interventions. WHAT THIS PAPER ADDS: There is uncertainty whether new onset problem behaviours or a change in longstanding problem behaviours should be considered as symptoms of depression or other types of psychiatric disorders in adults with intellectual disabilities. The validity of previous studies was limited by the use of pre-defined, categorical diagnoses or unreliable statistical methods. This study used robust statistical modelling to examine problem behaviours within a dimensional model of symptoms. We found that problem behaviours were included in an emotional dysregulation dimension and not in the dimension that included symptoms that are typical of depression. The dimensional model of symptoms had greater predictive validity than categorical diagnoses of psychiatric disorders. Our findings suggest that problem behaviours are a final common pathway for emotional distress in adults with intellectual disabilities so clinicians should not use a change in problem behaviours as a diagnostic criterion for depression, or other psychiatric disorders.

Psychosis and adults with intellectual disabilities. Prevalence, incidence, and related factors.

OBJECTIVE: To determine the point prevalence, incidence, and remission over a 2-year period of psychosis in adults with intellectual disabilities, and to investigate demographic and clinical factors hypothesised to be associated with psychosis. METHOD: A population-based cohort of adults with intellectual disabilities (n = 1,023) was longitudinally studied. Comprehensive face-to-face mental health assessments to detect psychosis, plus review of family physician, psychiatric, and psychology case notes were undertaken at two time points, 2 years apart. RESULTS: Point prevalence is 2.6% (95% CI = 1.8-3.8%) to 4.4% (95% CI = 3.2-5.8%), dependant upon the diagnostic criteria employed. Two-year incidence is 1.4% (95% CI = 0.6-2.6), and for first episode is 0.5% (95% CI = 0.1-1.3). Compared with the general population, the standardised incidence ratio for first episode psychosis is 10.0 (95% CI = 2.1-29.3). Full remission after 2 years is 14.3%. Visual impairment, previous long-stay hospital residence, smoking, and not having epilepsy were independently associated with psychosis, whereas other factors relevant to the general population were not. CONCLUSIONS: The study of psychosis in persons with intellectual disabilities benefits the population with intellectual disabilities, and advances the understanding of psychosis for the general population. Mental health professionals need adequate knowledge in order to address the high rates of psychosis in this population.

Mental ill-health in adults with intellectual disabilities: prevalence and associated factors.

BACKGROUND: Reported prevalence of mental ill-health among adults with intellectual disabilities ranges from 7 to 97%, owing to methodological limitations. Little is known about associations. AIMS: To determine the prevalence of mental ill-health in adults with intellectual disabilities and to investigate factors independently associated with it. METHOD: Population-based study (n=1023) with comprehensive individual assessments modelled using regression analyses. RESULTS: Point prevalence of mental ill-health was 40.9% (clinical diagnoses), 35.2% (DC-LD), 16.6% (ICD-10-DCR) and 15.7% (DSM-IV-TR). The most prevalent type was problem behaviours. Mental ill-health was associated with more life events, female gender, type of support, lower ability, more consultations, smoking, incontinence, not having severe physical disabilities and not having immobility; it was not associated with deprived areas, no occupation, communication impairment, epilepsy, hearing impairment or previous institutional residence. CONCLUSIONS: This investigation informs further longitudinal study, and development of appropriate interventions, public health strategy and policy. ICD-10-DCR and DSM-IV-TR undercount mental ill-health in this population compared with DC-LD.

An epidemiological investigation of affective disorders with a population-based cohort of 1023 adults with intellectual disabilities.

BACKGROUND: Intellectual disabilities (ID) are common and lifelong. People with ID have health inequalities compared with the general population, but little is known about the epidemiology of affective disorders in this population. This study was undertaken to determine the point prevalence of affective disorders, and to investigate factors associated with depression. METHOD: This population-based study (n=1023) included comprehensive individual assessments with each person. A two-stage process was used for diagnosis of affective disorders. Factors independently associated with depression were investigated through logistic regression analysis. RESULTS: The point prevalence was higher than that reported previously for the general population; DC-LD yielded 3.8% for depression and 0.6% for mania. Additionally, 1.0% had bipolar disorder currently in remission, and 0.1% first episode of mania currently in remission. Similar to general population findings, depression was associated with female gender, smoking, number of preceding family physician appointments, and preceding life events. Important differences were the association of not having a hearing impairment, and the trends for not living in deprived areas, and being married. Unlike general population findings, not having daytime occupation and obesity were not independently associated; nor was previous long-stay hospital residence, severity of ID, or sensory impairments. CONCLUSIONS: This study has found a high point prevalence of affective disorders in adults with ID. The factors associated with depression have differences to general population findings. An understanding of this is important in order to develop appropriate interventions, public strategy and policy, to reduce existing health inequalities.

Incidence and predictors of mental ill-health in adults with intellectual disabilities: prospective study.

BACKGROUND: The point prevalence of mental ill-health among adults with intellectual disabilities is 40.9%, but its incidence is unknown. AIMS: To determine the incidence and possible predictors of mental ill-health. METHOD: Prospective cohort study to measure mental ill-health in adults with mild to profound intellectual disabilities. RESULTS: Cohort retention was 70% (n=651). The 2-year incidence of mental ill-health was 16.3% (12.6% excluding problem behaviours, and 4.6% for problem behaviours) and the standardised incidence ratio was 1.87 (95% CI1.51-2.28). Factors related to incident mental ill-health have some similarities with those in the general population, but also important differences. Type of accommodation and support, previous mental ill-health, urinary incontinence, not having impaired mobility, more severe intellectual disabilities, adult abuse, parental divorce in childhood and preceding life events predicted incident ill-health; however, deprivation, other childhood abuse or adversity, daytime occupation, and marital and smoking status did not. CONCLUSIONS: This is a first step towards intervention trials, and identifying subpopulations for more proactive measures. Public health strategy and policy that is appropriate for this population should be developed.

Intellectual disabilities, depressive episode, diagnostic criteria and Diagnostic Criteria for Psychiatric Disorders for Use with Adults with Learning Disabilities/Mental Retardation (DC-LD).

BACKGROUND: Depressive episode is one of the most common types of psychiatric illness that occurs in adults with intellectual disabilities. METHODS: A comprehensive literature search was undertaken using Medline, PsychLIT and hand-searching of key journals. This paper reviews the evidence and integrates findings, to report how evidence relates to the development of the new Diagnostic Criteria for Psychiatric Disorders for Use with Adults with Learning Disabilities/Mental Retardation[DC-LD] depressive episode criteria. RESULTS: This area is better researched than many others, providing evidence on clinical symptomatology and presentation. In view of the lack of utility of standard diagnostic criteria developed for use with the general population, and set within the historical context, there are clearly identified reasons for the introduction of DC-LD. The depressive episode category has been informed by the evidence, and field trials showed excellent validity compared with the gold standard of learning disabilities psychiatric assessment. CONCLUSIONS: The DC-LD depressive episode category may improve clinical diagnosis and facilitate research. Its usefulness and limitations are yet to be determined in detail.