10
Psychiatric service use and psychiatric disorders in adults with intellectual disability S. Bhaumik, 1,2 F. C. Tyrer, 1 C. McGrother 1 & S. K. Ganghadaran 2 1 Department of Health Sciences, University of Leicester, Leicester, UK 2 Leicestershire Partnership NHS Trust, Leicester Frith Hospital, Leicester, UK Abstract Background UK policies aim to facilitate access to general psychiatric services for adults with intellec- tual disability (ID). If this is to be achieved, it is important to have a clear idea of the characteristics and proportion of people with ID who currently access specialist psychiatric services and the nature and extent of psychiatric disorders in this population. Methods A cross-sectional study was carried out on all adults with ID using specialist services in Leicestershire and Rutland, UK, between 2001 and 2006. Characteristics of individuals seen by psychi- atric services and the nature and prevalence of psy- chiatric disorders were investigated. Results Of 2711 adults identified, 1244 (45.9%) accessed specialist psychiatric services at least once during the study period. Individuals attending psy- chiatric services were more likely to be older and to live in residential settings; they were less likely to be south Asian or to have mild/moderate ID. The prevalence of psychiatric disorders among the total study population was 33.8%; the most common dis- orders were behaviour disorder (19.8%) and autistic spectrum disorders (8.8%). Epilepsy was highly prevalent (60.8%) among those attending psychiat- ric services without a mental health diagnosis. Behaviour disorders and autistic spectrum disorders were more common in men and in adults with severe/profound ID, whereas schizophrenia and organic disorders were more common in women and in adults with mild/moderate ID. Depression was also more common in women with ID. Conclusions Psychiatric disorders and specialist health problems are common among adults with ID and the profile of psychiatric disorders differs from that found in general psychiatry. Close collaboration between general and specialist service providers is needed if the current move towards use of general psychiatric services in this population is to be achieved. The measures should include a clear care pathway for people with ID and mental health problems to facilitate the smooth transfer of patients between specialist and generic mental health services and arrangements for joint working where input from both services is required. The commissioning framework for such processes should be in place with appropriate pooling of resources. Keywords intellectual disability, psychiatric disorders, prevalence, mental health services and access Introduction Concern over health inequalities faced by adults with intellectual disability (ID) has led to a number of policy initiatives aimed at facilitating access to Correspondence: Dr Sabyasachi Bhaumik, Leicester Frith Hospi- tal, Groby Road, Leicester LE39QF, UK (e-mail: bhaumikuk@ yahoo.co.uk). Journal of Intellectual Disability Research doi: 10.1111/j.1365-2788.2008.01124.x volume 52 part 11 pp 986995 november 2008 986 © 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd

Psychiatric service use and psychiatric disorders in adults with intellectual disability

Embed Size (px)

Citation preview

Page 1: Psychiatric service use and psychiatric disorders in adults with intellectual disability

Psychiatric service use and psychiatric disorders inadults with intellectual disability

S. Bhaumik,1,2 F. C. Tyrer,1 C. McGrother1 & S. K. Ganghadaran2

1 Department of Health Sciences, University of Leicester, Leicester, UK2 Leicestershire Partnership NHS Trust, Leicester Frith Hospital, Leicester, UK

Abstract

Background UK policies aim to facilitate access togeneral psychiatric services for adults with intellec-tual disability (ID). If this is to be achieved, it isimportant to have a clear idea of the characteristicsand proportion of people with ID who currentlyaccess specialist psychiatric services and the natureand extent of psychiatric disorders in thispopulation.Methods A cross-sectional study was carried outon all adults with ID using specialist services inLeicestershire and Rutland, UK, between 2001 and2006. Characteristics of individuals seen by psychi-atric services and the nature and prevalence of psy-chiatric disorders were investigated.Results Of 2711 adults identified, 1244 (45.9%)accessed specialist psychiatric services at least onceduring the study period. Individuals attending psy-chiatric services were more likely to be older and tolive in residential settings; they were less likely to besouth Asian or to have mild/moderate ID. Theprevalence of psychiatric disorders among the totalstudy population was 33.8%; the most common dis-orders were behaviour disorder (19.8%) and autisticspectrum disorders (8.8%). Epilepsy was highlyprevalent (60.8%) among those attending psychiat-ric services without a mental health diagnosis.

Behaviour disorders and autistic spectrum disorderswere more common in men and in adults withsevere/profound ID, whereas schizophrenia andorganic disorders were more common in womenand in adults with mild/moderate ID. Depressionwas also more common in women with ID.Conclusions Psychiatric disorders and specialisthealth problems are common among adults with IDand the profile of psychiatric disorders differs fromthat found in general psychiatry. Close collaborationbetween general and specialist service providers isneeded if the current move towards use of generalpsychiatric services in this population is to beachieved. The measures should include a clear carepathway for people with ID and mental healthproblems to facilitate the smooth transfer ofpatients between specialist and generic mentalhealth services and arrangements for joint workingwhere input from both services is required. Thecommissioning framework for such processesshould be in place with appropriate pooling ofresources.

Keywords intellectual disability, psychiatricdisorders, prevalence, mental health services andaccess

Introduction

Concern over health inequalities faced by adultswith intellectual disability (ID) has led to a numberof policy initiatives aimed at facilitating access to

Correspondence: Dr Sabyasachi Bhaumik, Leicester Frith Hospi-tal, Groby Road, Leicester LE3 9QF, UK (e-mail: [email protected]).

Journal of Intellectual Disability Research doi: 10.1111/j.1365-2788.2008.01124.x

volume 52 part 11 pp 986–995 november 2008986

© 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd

Page 2: Psychiatric service use and psychiatric disorders in adults with intellectual disability

generic services, enabling adults with ID to feelsocially valued and to live as independently aspossible (Department of Health 2001, 2006; USDepartment of Health and Human Services 2002).This includes improving access to general psychiat-ric services for adults with ID and co-existingmental health problems. In the UK the movetowards use of general psychiatric services hasproved difficult, largely because of lack of experi-ence, resources and skills needed in general psy-chiatry to treat the complex co-existing health andbehaviour problems in this client group (Bouraset al. 1995; Chaplin 2004). The prevalence ofgeneral and specialist psychiatric service use amongadults with ID is currently unclear because ameasure of the underlying ID population in indi-vidual catchment areas is generally not available.However, it is recognised that most people withmoderate to profound ID are still seen by specialistpsychiatric services (Chaplin 2004), while thosewith mild ID, who generally have fewer complexhealth needs and greater potential for indepen-dence, may be more likely to benefit from access togeneral psychiatric services with support from spe-cialist services (Alexander et al. 2002; Royal Collegeof Psychiatrists 2003).

Undoubtedly psychiatry plays an importantservice role in this area. Psychiatric disorders arehighly prevalent in adults with ID, with population-based studies reporting rates of between 30% and41% (Lund 1985; Cooper et al. 2007), which arehigher than the prevalence estimates of 16–20% inthe general population (US Department of Healthand Human Services 1999; Singleton et al. 2001).Other studies show varying rates between 12% and60% (Jacobson 1982; Iverson & Fox 1989; Reiss1990; Deb et al. 2001; Taylor et al. 2004), depend-ing on the case mix of the study populations andthe identification and definitional criteria used.Making an accurate psychiatric diagnosis is difficultin this population because many people with IDhave communication deficits and associated physicalhealth problems, which complicate the use of avail-able diagnostic criteria.

In order for general psychiatric services tobecome more responsive to the mental health needsof adults with ID in the UK, it is important to havea clear idea of the characteristics and proportion ofpeople with ID who currently access specialist psy-

chiatric services and the nature and extent of psy-chiatric disorders in this population.

The aims of this study were:1 To describe the prevalence of specialist psychiat-ric service use among adults with ID;2 To describe the nature and prevalence of psychi-atric disorders in adults with ID; and3 To identify any differences in the nature andprevalence of psychiatric disorders between menand women and between different severity levels ofID.

Methods

Description of the service and population served

This was a cross-sectional study of all adults withadministratively defined ID in Leicestershire(including the city of Leicester) and Rutland, UK.This geographic location has a population of 0.7million adults (aged 19 years or over), of whomapproximately 8% are of south Asian origin(National Statistics 2007), and is similar in socio-economic terms to the UK as a whole. The preva-lence of psychiatric disorders in adults with ID wasdetermined using information on adult inpatientsand outpatients (aged 19 years or over) seen by spe-cialist ID psychiatric services in this geographicallocation between 1 January 2001 and 31 December2006. The Learning Disability Service in Leicester-shire is hosted by the mental health trust and pro-vides a range of specialist health interventions foradults with ID. These include psychiatry, psychol-ogy, speech and language therapy, occupationaltherapy and physiotherapy. Referrals to psychiatricservices are routed through general practitioners.There is a 12-bedded specialist ID inpatient unitand service users with mild ID are able to accessgeneral psychiatry inpatient beds where appropriate.

Data collection

Starting from year 2000, all psychiatric diagnoses(more than one per patient where appropriate) ofpatients using specialist psychiatric services forpeople with ID have been recorded using Interna-tional Classification of Disease (ICD)-10 diagnosticcriteria (World Health Organisation 1992). Thesediagnoses were based on clinical assessments by the

987Journal of Intellectual Disability Research volume 52 part 11 november 2008

S. Bhaumik et al. • Psychiatric service use and mental illness

© 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd

Page 3: Psychiatric service use and psychiatric disorders in adults with intellectual disability

respective consultant psychiatrists and wererecorded in a database along with other details,including age, sex, ethnicity, residential status of thepatient, comorbidity (epilepsy, mobility problems,visual and hearing impairments) and any prescribedmedication.

A measure of the underlying population wasassessed using individuals on the LeicestershireLearning Disability Register who had participatedin a home interview over the same 6-year studyperiod. The register has been described in detailelsewhere (McGrother et al. 1993); briefly it is anopen cohort of adults (aged 19 years or over) livingin and using specialist services (notified via a widerange of service providers) in Leicestershire andRutland, UK. Notification to the register is basedon a diagnosis of ID (World Health Organisation1992) with deficits in adaptive functioning (Heber1959) and a probable need for long-term support.As the register can only capture information ofpeople with ID who require support from social,health, voluntary or independent sector services, thenumber of people recorded in the register comprisethe administrative prevalence of ID in Leicestershireand Rutland. All adults seen by specialist psychiat-ric services in Leicestershire are on the register.Some people with mild ID may access mainstreamservices without being identified as having ID andare therefore not known to the register. Currentlyit is not possible to identify the size of thispopulation.

The register supports a programme of structuredhome interviews, for which the current acceptancerate is 91%, that are carried out with carers andclients every 5 to 7 years. Interviews incorporate theDisability Assessment Schedule (Holmes et al.1982) and include questions on demographicdetails, skill level, behaviour and carer stress. Sever-ity level of ID is determined from seven questionson communication, skill level and dependency,which have been validated against scores from theVineland scale (survey form) (Sparrow et al. 1984;Tyrer et al. 2008). Using this assessment, develop-mental age was estimated and the sample was cat-egorised into four severity levels following the WorldHealth Organisation’s ICD-10 criteria (WorldHealth Organisation 1992): mild (approx. IQ50–69), moderate (approx. IQ 35–49), severe(approx. IQ 20–34) and profound (approx.

IQ < 20). Individuals with an unknown or border-line level of ID (approx. IQ � 70) (n = 134) wereexcluded from the analysis.

At the time of being interviewed by register staff,people with ID and their families are informed thatthe information in an anonymised format may beused for research purposes. We did not seek consentspecifically for this study as seeking consent retro-spectively was felt to be inappropriate in this situa-tion. ICD diagnostic coding is routinely carried outduring psychiatric interviews in order to fulfill per-formance objectives set out by the Department ofHealth and to inform primary care physicians. Afterconsidering the above information, the DerbyshireResearch Ethics Committee gave ethical approvalfor this study.

Statistical methods

The population was stratified by psychiatric serviceattendance and described for sex, age group, resi-dential status and level of ID. The prevalence andnature of the psychiatric disorders were reported bysex and severity of ID. Data were analysed usingthe chi-squared test (or a two-tailed Fisher’s exacttest where the expected cell frequency was below5). Analyses were carried out in Stata version 9.0.

Results

In the 6-year period between 2001 and 2006, 1244

(45.9%) adults were seen by specialist psychiatricservices in Leicestershire, of whom 707 (56.8%)were men and 537 (43.2%) were women (Table 1).Most adults were living in residential homes(38.4%) and had severe or profound ID (72.1%).Among those seen by services, 479 (38.5%) adultshad epilepsy and 814 (65.4%) adults were pre-scribed psychotropic medication (including anti-epileptic drugs). No sex differences were observedbetween adults who accessed specialist psychiatricservices and those who did not. However, thosewho saw a psychiatrist were less likely to be aged<30 years, more likely to be living in residentialaccommodation, and less likely to have mild ormoderate ID (Table 1).

The prevalence of psychiatric disorders in thestudy population was 33.8% (n = 915) (Table 2).

988Journal of Intellectual Disability Research volume 52 part 11 november 2008

S. Bhaumik et al. • Psychiatric service use and mental illness

© 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd

Page 4: Psychiatric service use and psychiatric disorders in adults with intellectual disability

The most common psychiatric disorders werebehaviour disorder, diagnosed in 19.8% of adults,followed by autistic spectrum disorders (8.8%)(autism, Asperger’s syndrome, atypical autism andunspecified pervasive developmental disorders),depression (4.3%) and bipolar affective disorders(3.0%). Of interest, 12.1% (n = 329) of individualswho attended specialist psychiatric services did nothave a diagnosis of a psychiatric disorder; themajority of these individuals (60.8%; n = 200) hadepilepsy.

No differences were observed in the overallprevalence of psychiatric disorders between menand women. However, there were substantial sex

differences in diagnoses of individual psychiatricdisorders. Men were more likely to have a diagnosisof autistic spectrum disorder, behaviour disorder orother psychiatric disorders. Women were more likelyto have a diagnosis of schizophrenia depression ororganic disorder.

Psychiatric service attendance was more commonas individuals’ severity of ID increased; the propor-tion of adults with mild, moderate, severe and pro-found ID who accessed psychiatric services was29.8%, 33.7%, 47.1% and 65.4%, respectively.These proportions were reflected in the prevalenceof psychiatric disorders in this population; justunder one-quarter (24.2%) of adults with mild ID

Table 1 Characteristics of the study population

Characteristic

Psychiatricassessment

No psychiatricassessment

P-valuen (%) n (%)

All individuals 1244 (100.0) 1467 (100.0)Sex

Men 707 (56.8) 819 (55.8) 0.60Women 537 (43.2) 648 (44.2)

Age group*19–29 254 (20.4) 515 (35.1) <0.00130–39 296 (23.8) 346 (23.6)40–49 291 (23.4) 287 (19.6)50–59 238 (19.1) 168 (11.5)60+ 165 (13.3) 151 (10.3)

Ethnic groupWhite 1082 (87.0) 1196 (81.5) <0.001South Asian 111 (8.9) 237 (16.2)Other/unknown 51 (4.1) 32 (2.2)

Residential status†

Independent 53 (4.3) 153 (10.4) <0.001Living with family 341 (27.4) 817 (55.7)Supported living/voluntary 116 (9.3) 113 (7.7)

Residential home 478 (38.4) 245 (16.7)Social services hostel 38 (3.1) 25 (1.7)NHS accommodation 130 (10.5) 22 (1.5)Other/not known 88 (7.1) 84 (5.7)Level of ID

Mild 160 (12.9) 377 (25.7) <0.001Moderate 187 (15.0) 368 (25.1)Severe 414 (33.3) 466 (31.8)Profound 483 (38.8) 256 (17.5)

* Age at assessment or date of home interview (for individuals without an assessment).† Residence on date of assessment or date of home interview (for individuals without an assessment).ID, intellectual disability; NHS, National Health Service.

989Journal of Intellectual Disability Research volume 52 part 11 november 2008

S. Bhaumik et al. • Psychiatric service use and mental illness

© 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd

Page 5: Psychiatric service use and psychiatric disorders in adults with intellectual disability

had a diagnosis of psychiatric disorders, comparedwith 27.4%, 34.3% and 44.8% in people with mod-erate, severe and profound ID, respectively. Psychi-atric diagnoses varied among adults with differentlevels of ID. Those with mild and moderate ID gen-erally had more diagnoses of schizophrenia and per-sonality disorders, whereas those with severe andprofound ID had higher rates of organic disorders,autistic spectrum disorders and behaviour disorders(Table 3).

Discussion

Specialist psychiatric service use was commonamong adults with ID living in Leicestershire andRutland, UK. Of 2711 individuals, 45.9% accessedpsychiatric services at least once during the 6-yearstudy period. More than one-third (33.8%) ofadults in the study population had a psychiatricdiagnosis. However, the most common disorderswere behaviour disorder (19.8%) and autistic spec-trum disorders (8.8%).

It is difficult to make direct comparisons betweenthis study and the prevalence of psychiatric serviceuse among adults in the general population becausethe majority of the literature in this area isrestricted to people with emotional or mental healthproblems. However, using data from the generalpopulation presented in two large-scale question-naire studies, the proportion of adults who reportedhaving seen a psychiatrist in the preceding 12

months was approximately 1.2% in Europe (TheESEMeD/MHEDEA 2000 Investigators 2004) and2.8% in the United States (Wang et al. 2005).Direct comparisons are limited as both studies usedweighted prevalence figures, and their populationsrelied on self-report among non-institutionalisedadults who saw a psychiatrist over a 1-year period(as opposed to 6 years for our study). Nonetheless,given that our prevalence figure is more than 15

times higher than these estimates, it is reasonableto assume that psychiatric service use is morecommon in adults with ID. Greater access to ser-vices in this population is likely to reflect increased

Table 2 The prevalence of psychiatric disorders (per cent) in adults with intellectual disabilities by sex

Diagnostic category ICD-10 diagnoses

Males(n = 1526)%

Females(n = 1185)% P-value

All(n = 2711)%

Psychotic disordersSchizophrenia F20.x 1.7 3.0 0.02 2.2Other psychotic disorders F21–F23.x, F25.x, F28–F29.x 1.8 1.7 0.77 1.8

Affective disordersDepressive disorder F32–F33.x 3.2 5.7 0.001 4.3Bipolar affective disorder F30–F31.x 2.7 3.4 0.30 3.0Other/unspecified F34.x, F38–F39.x 0.9 1.4 0.15 1.1

Anxiety disordersObsessive compulsive disorder F42.x 0.3 0.4 0.76 0.4Other anxiety disorder F40–F41.x, F43–F45.x 2.4 1.8 0.24 2.1

Other psychiatric disordersOrganic disorder F00–F03.x, F05–F07.x, F09.x 1.5 2.9 0.01 2.1Alcohol/substance use disorder F10.x, F12.x, F18.x, F19.x 0.1 0.1 0.59 0.1Sleep disorder F51.x 0.2 0.1 0.64 0.2Autistic spectrum disorder F84.x 10.4 6.7 0.001 8.8Behaviour disorder F70.1, F71.1, F72.1, F73.1 22.0 16.9 0.001 19.8Personality disorder F60.x, F61.x 1.1 1.6 0.20 1.3Other F50.x, F52.x, F59.x, F62–F63.x,

F65–F66.x1.1 0.1 0.001 0.7

Psychiatric disorders of any type Any of above 34.0 33.4 0.75 33.8Total presenting to psychiatric services – 46.3 45.3 0.60 45.9

ICD, International Classification of Disease.

990Journal of Intellectual Disability Research volume 52 part 11 november 2008

S. Bhaumik et al. • Psychiatric service use and mental illness

© 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd

Page 6: Psychiatric service use and psychiatric disorders in adults with intellectual disability

prevalence of behaviour disorder (Emerson et al.2001), autistic spectrum disorders (Gillberg &Soderstrom 2003) and co-existing health problems,such as epilepsy (McGrother et al. 2006). We foundthat individuals with epilepsy comprised the great-est proportion (60.8%) of those who attended ser-vices but did not have a psychiatric diagnosis, whichillustrates that not all conditions treated in specialistpsychiatry are mental health-related.

The prevalence of psychiatric disorders in thisstudy was 33.8%. The most comparable studies thatreport on the prevalence of psychiatric disorder inadults with ID are population-based. These studiesreport figures of 29.9% (when restricted to adultswith a known IQ � 67) (Lund 1985) and 40.9%(Cooper et al. 2007). Both prevalence figures arebased on clinical diagnoses, but neither study usedICD-10 criteria. The latter study by Cooper et al.(2007) found that the prevalence of psychiatric dis-orders lowered when other diagnostic criteria (usingtwo psychopathology tools) were adopted [35.2%for DC-LD (Royal College of Psychiatrists 2001),16.6% for ICD-10-DCR (World Health Organisa-tion 1993) and 15.7% for DSM-IV-TR (American

Psychiatric Association 2000)]. The higher preva-lence of psychiatric disorders reported in Cooperet al.’s study is also likely to reflect their screeningall adults with ID, whereas we were only able toassess those who presented to psychiatric services.In keeping with the principles of inclusion, it islikely that many adults with mild ID were treated inthe primary care sector or by mainstream psychiat-ric services, sometimes without the knowledge ofthe specialist service concerned. Further, access tosupport is likely to be affected by confidence inhealthcare professionals, stigma and awareness ofmental health problems. These influences may beparticularly relevant to adults living in family set-tings who were less likely to access specialist psychi-atric services in this study.

Comparisons between the prevalence of psychiat-ric disorders in adults with ID and the generalpopulation are again limited because there are sub-stantial differences in diagnoses between the twopopulations. Behaviour disorder, for example, is nottreated as a psychiatric diagnosis in the generalpopulation. On excluding individuals with behav-iour disorder from the study, the prevalence of psy-

Table 3 The prevalence of psychiatric disorders (per cent) in adults with intellectual disabilities (ID) by severity of ID

Diagnostic category

Mild(n = 537)%

Moderate(n = 555)%

Severe(n = 880)%

Profound(n = 739)% P-value

Psychotic disordersSchizophrenia 3.7 3.8 1.9 0.5 <0.001Other psychotic disorders 1.9 2.0 2.5 0.7 0.05

Affective disordersDepressive disorder 4.5 5.1 4.8 3.0 0.22Bipolar affective disorder 2.4 3.4 2.8 3.3 0.75Other/unspecified 1.5 0.5 0.8 1.6 0.18

Anxiety disordersObsessive compulsive disorder 0.0 0.5 0.7 0.1 0.11Other anxiety disorder 1.7 2.7 2.1 2.2 0.70

Other psychiatric disordersOrganic disorder 0.2 1.6 2.5 3.4 0.001Alcohol/substance use disorder 0.2 0.4 0.0 0.0 0.09Sleep disorder 0.0 0.0 0.2 0.3 0.61Autistic spectrum disorder 4.3 4.5 8.1 16.1 <0.001Behaviour disorder 10.4 11.9 20.1 32.1 <0.001Personality disorder 3.0 1.8 1.0 0.0 <0.001Other 0.7 1.3 0.5 0.4 0.25

Psychiatric disorders of any type 24.2 27.4 34.3 44.8 <0.001Total presenting to psychiatric services 29.8 33.7 47.1 65.4 <0.001

991Journal of Intellectual Disability Research volume 52 part 11 november 2008

S. Bhaumik et al. • Psychiatric service use and mental illness

© 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd

Page 7: Psychiatric service use and psychiatric disorders in adults with intellectual disability

chiatric disorders was 20.2%, and was 28.3% inCooper et al.’s (2007) study, which is closer to therates found in the general population (US Depart-ment of Health and Human Services 1999; Single-ton et al. 2001). It is probable, however, that somebehaviours mask undetected psychiatric disorders,particularly personality disorders, which have beenfound to overlap considerably with behaviourdisorder in people with ID (Corbett 1979; Deb &Hunter 1991). This may in part explain why theprevalence of personality disorders was lower in ourstudy (1.3%) and Cooper et al.’s study (1.0%)(Cooper et al. 2007) than in the general population(4.4%) (Singleton et al. 2001).

One of the surprise findings was the higherprevalence of schizophrenia in women. It is possiblethat women with ID felt more comfortable access-ing specialist psychiatric services than men. Theywere also more likely to have a diagnosis of depres-sion than men, which follows the pattern found inthe general population (Singleton et al. 2001).However, we observed no differences in the pres-ence of anxiety disorders between men and womenwith ID, which differs from the general population(Singleton et al. 2001) and which may be explainedby the higher prevalence of autistic spectrum disor-ders among men who present with anxiety-likesymptoms. We also found that men were more likelyto display behaviour problems, whereas most of theliterature in this area suggests that there are nodifferences in the overall prevalence of behaviourproblems between men and women with ID (Smithet al. 1996; Cooper et al. 2007). It is well recognisedthat the manifestation of behaviour problems tendsto be different in men and women with ID; men aremore likely than women to show overtly aggressivebehaviour such as physical or verbal aggression ordestructive behaviour (McClintock et al. 2003;Tyrer et al. 2006). These types of behaviours maybe more difficult for carers to manage and lead totheir seeking specialist psychiatric service support.

The higher prevalence of psychiatric disordersobserved in adults with severe and profound ID issomewhat supported in previous population-basedresearch (Birch et al. 1970; Borthwick-Duffy 1994;Cooper et al. 2007). However, this relationship isdifficult to ascertain because the ability to makeaccurate diagnoses also depends on the patient’sability level. There is a danger that the prevalence of

psychiatric disorders in adults with severe and pro-found ID is under-estimated because these patientsoften present with unremarkable symptoms [knownas ‘psychological masking’ (Crews et al. 1994)] andgenerally have greater communication deficits, thusare unable to report their own symptoms. In thelatter situation, diagnoses are reliant on clinicians’judgement and on secondary information fromcarers. Schizophrenia in particular is often difficultto identify in people with ID because symptomssuch as hallucinations and delusions are extremelydifficult to detect (Reid 1993). This may explainwhy diagnoses of schizophrenia were more commonin adults with mild and moderate ID.

This is a large study and has the advantage ofbeing population-based. A wide range of serviceproviders are used within the Leicestershire Learn-ing Disability Register notification network and theprevalence rate of 3.9 per 1000 population for theadministrative prevalence of ID compares favour-ably with other UK studies (Lawrenson et al. 1997;Cooper et al. 2007) and provides a representativesample of adults with moderate to profound ID(ten Horn et al. 1986). It is recognised, however,that register studies do not contain a representativesample of adults with mild ID because these adultsare less likely to access specialist support. Nonethe-less, 6% (n = 160) of the total study population hadmild ID and attended specialist psychiatric services,which suggests that in some cases adults may havehad more complex mental health needs that genericservices felt less able to manage effectively.

Our findings indicate that adults with ID have arange of complex mental health problems for whichthey seek support from specialist psychiatric ser-vices. The move towards general psychiatric serviceuse in this population needs careful consideration,particularly with regard to the necessary resources,skills and expertise in the management ofco-existing behaviour problems and the additionalhealth needs of this client group.

Practical solutions identified locally

The Learning Disability Service being part of amental health trust locally has helped us to secure acommitment from generic psychiatric services inallowing access for people with mild ID. Throughan interface group between Learning Disability

992Journal of Intellectual Disability Research volume 52 part 11 november 2008

S. Bhaumik et al. • Psychiatric service use and mental illness

© 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd

Page 8: Psychiatric service use and psychiatric disorders in adults with intellectual disability

and General Adult psychiatric services, we havedeveloped a protocol to facilitate appropriatetransfer of patients between services where possibleand joint working where management by a singleservice is unlikely to be of help for the serviceuser. Development of an ID clinical network tofacilitate the joint working, pooling of resources incertain areas such as crisis interventions and appro-priate level of training and support is currentlyunderway.

Limitations of the study

The sample includes only people who access spe-cialist ID services and therefore individuals withmild ID and psychiatric disorders are likely to beare under-represented in this population. There isno current system to capture those with mild IDwho access mainstream services, as these individu-als are not always identified as having ID. However,a short screening tool has recently been developedin Leicestershire to help health professionals todetermine ID in this client group.

In this study psychiatric diagnoses were based onclinical assessment and were not subject to the useof a structured diagnostic tool. However, ICD-10

criteria were used to facilitate the process and inour opinion, this reflects real-life clinical practice.

Future research would benefit from identifyingthe complex process of accessing mainstream ser-vices by people with mild ID and service users’ andcarers’ experiences of this process. The developmentof short validated screening tool to help profession-als to identify people with mild ID in mainstreamservices may also be important.

Ethical approval

This study has Derbyshire Research EthicsCommittee approval.

Acknowledgements

The authors gratefully acknowledge LeicestershirePartnership NHS Trust and the Department ofHealth Policy Research Programme who providedfunding for this study and all clients and carers whoparticipated in the register home interviews.

References

Alexander R. T., Piachaud J. & Singh I. (2002) Two dis-tricts, two models: in-patient care in the psychiatry oflearning disability. British Journal of DevelopmentalDisabilities 47, 105–10.

American Psychiatric Association (2000) The Diagnosticand Statistical Manual of Mental Disorders, 4th edn.revised (DSM-IV-TR). American Psychiatric Associa-tion, Washington, DC.

Birch H. G., Richardson S. A., Baird D., Horobin G. &Illsey R. (1970) Mental Subnormality in the Community:A Clinical and Epidemiologic Study. Williams & Williams,Baltimore, MD.

Borthwick-Duffy S. A. (1994) Epidemiology and preva-lence of psychopathology in people with mental retarda-tion. Journal of Consulting and Clinical Psychology 62,17–27.

Bouras N., Holt G. & Gravestock S. (1995) Communitycare for people with learning disabilities: deficits andfuture plans. Psychiatric Bulletin 19, 134–7.

Chaplin R. (2004) General psychiatric services for adultswith intellectual disability and mental illness. Journal ofIntellectual Disability Research 48, 1–10.

Cooper S. A., Smiley E., Morrison J., Williamson A. &Allan L. (2007) Mental ill-health in adults with intellec-tual disabilities: prevalence and associated factors.British Journal of Psychiatry 190, 27–35.

Corbett J. A. (1979) Psychiatric morbidity and mentalretardation. In: Psychiatric Illness and Mental Handicap(eds F. E. James & R. P. Snaith), pp. 11–25. Gaskell,London.

Crews W. D., Bonaventura S. & Row F. (1994) Dual diag-nosis: prevalence of psychiatric disorders in a large scaleresidential facility for individuals with mental retarda-tion. American Journal of Mental Retardation 98, 688–731.

Deb S. & Hunter D. (1991) Psychopathology ofpeople with mental handicap and epilepsy. II:Psychiatric illness. British Journal of Psychiatry 159,826–30.

Deb S., Thomas M. & Bright C. (2001) Mentaldisorder in adults with intellectual disability. 1:Prevalence of functional psychiatric illness among acommunity-based population aged between 16 and 64

years. Journal of Intellectual Disability Research 45, 495–505.

Department of Health (2001) Valuing People. A NewStrategy for Learning Disability for the 21st Century.WhitePaper. HMSO, London.

Department of Health (2006) Our Health, Our Care, OurSay: A New Direction for Community Services. HMSO,London.

Emerson E., Kiernan C., Alborz A., Reeves D., MasonH., Swarbrick R. et al. (2001) The prevalence of chal-

993Journal of Intellectual Disability Research volume 52 part 11 november 2008

S. Bhaumik et al. • Psychiatric service use and mental illness

© 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd

Page 9: Psychiatric service use and psychiatric disorders in adults with intellectual disability

lenging behaviours: a total population study. Research inDevelopmental Disabilities 22, 77–93.

Gillberg C. & Soderstrom H. (2003) Learning disability.Lancet 362, 811–21.

Heber R. A. (1959) Manual on terminology of classifica-tion in mental retardation. American Journal of MentalDeficiency 64, 1–111.

Holmes N., Shah A. & Wing L. (1982) The DisabilityAssessment Schedule: A brief screening device for usewith the mentally retarded. Psychological Medicine 12,879–90.

ten Horn G. H. M. M., Giel R., Gulbinat W. H. & Hend-erson J. H. (1986) Psychiatric Cases Registers in PublicHealth: AWorldwide Inventory1960–1985 (p. 17). Elsevier,Amsterdam & Oxford.

Iverson J. C. & Fox R. A. (1989) Prevalence of psychopa-thology among mentally retarded adults. Research inDevelopmental Disabilities 10, 77–83.

Jacobson J. W. (1982) Problem behavior and psychiatricimpairment within a developmentally disabled popula-tion. I: Behaviour frequency. Applied Research in MentalRetardation 3, 121–39.

Lawrenson R., Rohde J., Bott C., Hambleton I. & FarmerR. (1997) Trends in the need for services for peoplewith learning disabilities: implications for primary care.Health Trends 29, 37–41.

Lund J. (1985) The prevalence of psychiatric morbidity inmentally retarded adults. Acta psychiatrica Scandinavica72, 563–70.

McClintock K., Hall S. & Oliver C. (2003) Riskmarkers associated with challenging behaviours inpeople with intellectual disabilities: a meta-analyticstudy. Journal of Intellectual Disability Research 47,405–16.

McGrother C. W., Hauck A., Burton P. R., Raymond N.T. & Thorp C. F. (1993) More and better services forpeople with learning disabilities. Journal of Public HealthMedicine 15, 263–71.

McGrother C. W., Bhaumik S., Thorp C. F., Hauck A.,Branford D. & Watson J. M. (2006) Epilepsy inadults with intellectual disabilities: prevalence,associations and service implications. Seizure 15,376–86.

National Statistics (2007) Mid-Year Population Estimates2005: Leicester, Leicestershire and Rutland. National Statis-tics, Durham.

Reid A. (1993) Schizophrenia and paranoid syndromes inpersons with mental retardation: assessment and diag-nosis. In: Mental Health Aspects of Mental Retardation(eds R. J. Fletcher & A. Dosen), pp. 98–110. LexingtonBooks, New York.

Reiss S. (1990) Prevalence of dual diagnosis incommunity-based day programs in the Chicago metro-politan area. American Journal of Mental Retardation 94,578–85.

Royal College of Psychiatrists (2001) DC-LD: DiagnosticCriteria for Psychiatric Disorders for Use with Adults withLearning Disabilities/Mental Retardation (Occasional PaperOP48). Gaskell, London.

Royal College of Psychiatrists (2003) Meeting the MentalHealth Needs of Adults with a Mild Learning Disability(Council Report CR115). Royal College of Psychiatrists,London.

Singleton N., Bumpstead R., O’Brien M., Lee A. &Meltzer H. (2001) Psychiatric Morbidity among AdultsLiving in Private Households, 2000. The StationeryOffice, London.

Smith S., Branford D., Collacott R. A., Cooper S. A.& McGrother C. (1996) Prevalence and clustertypology of maladaptive behaviours in ageographically defined population of adults withlearning disabilities. British Journal of Psychiatry 169,219–27.

Sparrow S. S., Balla D. A. & Cichetti D. V. (1984)Vineland Adaptive Behavior Scales: Interview edition,Survey Form. American Guidance Service, CirclePines, MN.

Taylor J. L., Hatton C., Dixon L. & Douglas C. (2004)Screening for psychiatric symptoms: PAS-ADDChecklist norms for adults with intellectualdisabilities. Journal of Intellectual Disability Research 48,37–41.

The ESEMeD/MHEDEA 2000 Investigators (2004) Useof mental health services in Europe: results from theEuropean Study of the Epidemiology of Mental Disor-ders (ESEMeD) project. Acta Psychiatrica Scandinavica109(Suppl. 420), 47–54.

Tyrer F., McGrother C. W., Thorp C. F., Donaldson M.,Bhaumik S., Watson J. M. et al. (2006) Physical aggres-sion towards others in adults with learning disabilities:prevalence and associated factors. Journal of IntellectualDisability Research 50, 295–304.

Tyrer F., McGrother C. W., Thorp C. F., Taub N. A.,Bhaumik S. & Cicchetti D. V. (2008) The LeicestershireIntellectual Disability (LID) tool: a simple measure toidentify moderate to profound intellectual disability.Journal of Applied Research in Intellectual Disabilities 21,268–76.

US Department of Health and Human Services (1999)Mental Health: A Report of the Surgeon General. U.S.Department of Health and Human Services, SubstanceAbuse and Mental Health Services Administration,Center for Mental Health Services, National Institutesof Health, National Institute of Mental Health.Rockville, MD.

US Department of Health and Human Services (2002)Closing the Gap: A National Blueprint to Improve theHealth of Persons with Mental Retardation. Report of theSurgeon General’s Conference on Health Disparities andMental Retardation. Department of Health and HumanServices, Rockville, MD.

994Journal of Intellectual Disability Research volume 52 part 11 november 2008

S. Bhaumik et al. • Psychiatric service use and mental illness

© 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd

Page 10: Psychiatric service use and psychiatric disorders in adults with intellectual disability

Wang P. S., Lane M., Olfson M., Pincus H. A., Wells K.B. & Kessler R. C. (2005) Twelve-month use of mentalhealth services in the United States. Archives of GeneralPsychiatry 62, 629–40.

World Health Organisation (1992) The ICD-10 Classifica-tion of Mental and Behavioural Disorders: Clinical Descrip-tions and Diagnostic Guidelines. World HealthOrganisation, Geneva.

World Health Organisation (1993) The ICD-10 Classifica-tion for Mental and Behavioural Disorders: DiagnosticCriteria for Research. World Health Organisation,Geneva.

Accepted 11 August 2008

995Journal of Intellectual Disability Research volume 52 part 11 november 2008

S. Bhaumik et al. • Psychiatric service use and mental illness

© 2008 The Authors. Journal Compilation © 2008 Blackwell Publishing Ltd