587951 research-article2015
ANP0010.1177/0004867415587951ANZJP ArticlesChitty et al.
Research
Central nervous system medication use in older adults with intellectual disability: Results from the successful ageing in intellectual disability study
Australian & New Zealand Journal of Psychiatry 1–11 DOI: 10.1177/0004867415587951 © The Royal Australian and New Zealand College of Psychiatrists 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav anp.sagepub.com
Kate M Chitty1, Elizabeth Evans1, Jennifer J Torr2, Teresa Iacono3, Henry Brodaty4,5,6, Perminder Sachdev4,7 and Julian N Trollor1,4
Abstract Objective: Information on the rates and predictors of polypharmacy of central nervous system medication in older people with intellectual disability is limited, despite the increased life expectancy of this group. This study examined central nervous system medication use in an older sample of people with intellectual disability. Methods: Data regarding demographics, psychiatric diagnoses and current medications were collected as part of a larger survey completed by carers of people with intellectual disability over the age of 40 years. Recruitment occurred predominantly via disability services across different urban and rural locations in New South Wales and Victoria. Medications were coded according to the Monthly Index of Medical Specialties central nervous system medication categories, including sedatives/hypnotics, anti-anxiety agents, antipsychotics, antidepressants, central nervous system stimulants, movement disorder medications and anticonvulsants. The Developmental Behaviour Checklist for Adults was used to assess behaviour. Results: Data were available for 114 people with intellectual disability. In all, 62.3% of the sample was prescribed a central nervous system medication, with 47.4% taking more than one. Of those who were medicated, 46.5% had a neurological diagnosis (a seizure disorder or Parkinson’s disease) and 45.1% had a psychiatric diagnosis (an affective or psychotic disorder). Linear regression revealed that polypharmacy was predicted by the presence of neurological and psychiatric diagnosis, higher Developmental Behaviour Checklist for Adults scores and male gender. Conclusion: This study is the first to focus on central nervous system medication in an older sample with intellectual disability. The findings are in line with the wider literature in younger people, showing a high degree of prescription and polypharmacy. Within the sample, there seems to be adequate rationale for central nervous system medication prescription. Although these data do not indicate non-adherence to guidelines for prescribing in intellectual disability, the high rate of polypharmacy and its relationship to Developmental Behaviour Checklist for Adults scores reiterate the importance of continued medication review in older people with intellectual disability. Keywords Intellectual disability, challenging behaviour, central nervous system medication, polypharmacy
1Department
of Developmental Disability Neuropsychiatry, UNSW Australia, Sydney, NSW, Australia for Developmental Disability Health, Monash University, Notting Hill, VIC, Australia 3La Trobe Rural Health School, La Trobe University, Bendigo, VIC, Australia 4Centre for Healthy Brain Ageing, UNSW Australia, Sydney, NSW, Australia 5Dementia Collaborative Research Centre, UNSW Australia, Sydney, NSW, Australia 6Academic Department for Old Age Psychiatry, Prince of Wales Hospital, Randwick, NSW, Australia 7Neuropsychiatric Institute, Prince of Wales Hospital, Randwick, NSW, Australia 2Centre
Corresponding author: Julian N Trollor, Department of Developmental Disability Neuropsychiatry, UNSW Australia, 34 Botany St, UNSW, NSW 2052, Australia. Email: [email protected]
Australian & New Zealand Journal of Psychiatry
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ANZJP Articles
Introduction The prescription rates of central nervous system (CNS) medications to people with intellectual disability (ID) far exceed those within the general population. During 2011, within the Australian general population around 10% of people aged 45–54 years had accessed a CNS medication, increasing to around 25% in those aged 75 years and over – the largest rate across all age groups (ABS, 2011). In comparison, rates of CNS medication use are as high as 60% in adults with ID (Sachdev, 1991; Tsiouris et al., 2013), with limited representation within these samples of those aged 45 years and over. International studies also consistently report high rates of CNS medication polypharmacy (defined as more than one CNS medications) in ID, particularly of antipsychotics and anticonvulsants (Doan et al., 2013, 2014; Edelsohn et al., 2014; Hill et al., 1985; Sachdev, 1991; Thomas et al., 2010; Tsiouris et al., 2013). These findings raise concerns given the common adverse effects of these medications, which, especially in people with ID, can further exacerbate physical, mental, neurological and behavioural issues and markedly affect the quality of life (Allen, 2008; Matson et al., 2003; Thomas et al., 2010). Indeed, polypharmacy of CNS medication (as defined by the Monthly Index of Medical Specialties [MIMS]) in people with ID has been associated with an increased susceptibility to these side effects (Habetaler et al., 2014; Mahan et al., 2010). Compared with the general population, people with ID have been found to have higher rates of psychiatric diagnosis, especially psychotic and affective disorders (Cooper et al., 2007) and neurological diagnoses, especially seizure disorders (Bowley and Kerr, 2000; McGrother et al., 2006; Santosh and Baird, 1999). The high prevalence of these diagnoses indeed warrants CNS medication use; however, studies have shown that CNS medications in people with ID are commonly associated with treatment of challenging behaviours (McGillivray and McCabe, 2004; Matson and Neal, 2009). Challenging behaviours are defined as Culturally abnormal behaviours of such an intensity, frequency or duration that the physical safety of the person or others is likely to be placed in serious jeopardy or behaviour which is likely to seriously limit use of or result in the person being denied access to ordinary community facilities. (Emerson, 1995)
In a large Dutch study (n = 2373), about one-third of adults with ID were on an antipsychotic medication: for almost 60% of participants it was prescribed for challenging behaviours, with only 22% having a diagnosed psychiatric disorder and the remaining 18% with no reason specified for the CNS medication use (De Kuijper et al., 2010). Fleming et al. (1996) found that 69% of their sample (n = 118) was receiving CNS medication for challenging behaviour, whereas only 8% had a psychiatric diagnosis
(Fleming et al., 1996). Similarly, in a more recent Australian study of 117 adults with ID, antipsychotics were the most commonly prescribed medication class, and the presence of challenging behaviours and a psychiatric illness was significant predictors of their use (Doan et al., 2013). Prescription of CNS medication for challenging behaviour in the absence of a psychiatric diagnosis lacks consistent evidence to support its use (Deb and Unwin, 2007; Thomas et al., 2010; Tsiouris et al., 2013; Tyrer et al., 2009). This practice has occurred at least partly in response to the frequent occurrence of challenging behaviour in the ID population (Cooper et al., 2007), often presenting as non-specific symptoms requiring comprehensive multidisciplinary assessment and targeted intervention (WPA (SPID), 2010). Furthermore, impairments in communication and conceptual thought in ID present difficulties for psychiatric assessment and diagnosis and can lead to missed diagnosis and misdiagnosis (Torr, 2013). A recent Australian commissioned report recommended that medications should be kept to a minimum, with a review for adverse effects and efficacy conducted after 3–4 months and be removed from the treatment plan as safely and as soon as possible (Thomas et al., 2010). There is limited research into prescription of CNS medications for older people with ID, despite the increased life expectancy in this group (Patja et al., 2000; Torr and Davis, 2007) and a dearth of evidence available to inform policy and practice. A study that has preliminarily addressed this issue indicated that CNS medication appears particularly prevalent in the oldest age bracket, with 51% of participants aged 47 years and over on a psychotropic medication (Doan et al., 2013). Pary (1993) noted that rates of CNS medications increase with age from the 20–39 year age bracket to those over 55 years. This evidence is supported by reports indicating that once people with ID are placed on CNS medication, they are often continued with that prescription indefinitely without review (Thomas et al., 2010). The potential for polypharmacy in older adults is perhaps exacerbated by increased comorbidities. Compared with the general population, people with ID are at increased risk of a range of age-related health disorders, including frailty (Evenhuis et al., 2012), seizure disorders (McCarron et al., 2014), multimorbidity (Hermans and Evenhuis, 2014) and dementia (Cooper, 1997; for a review, see Evans et al., 2013). Given their multiple risk factors for medication side effects, the issue of medication use patterns in elders with ID warrants attention. The aim of this study was to examine CNS medication use in an Australian sample of older people with ID, with a particular focus on predictors of polypharmacy. We hypothesised that there would be a high rate of CNS medication use and polypharmacy among our older sample. We also hypothesised that challenging behaviours and psychiatric or neurological diagnoses would be significant predictors of CNS medication polypharmacy.
Australian & New Zealand Journal of Psychiatry Downloaded from anp.sagepub.com at University of Otago Library on November 10, 2015
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Chitty et al.
Methods
Measures
Participants
For this analysis, we used baseline questionnaire data from the SAge-ID study. An informant (a family member, paid carer or friend) completed a questionnaire about the person with ID, including detailed structured family history, adaptive behaviour, challenging behaviour, medical and psychiatric history, medication use, lifetime and current levels of physical activity, leisure/mental activity, social activity and occupational activity. The questionnaire took approximately 2 hours to complete. Specifically, the questionnaire included items regarding the person with ID’s age, gender, living status, known causes of ID (if any) and lifetime diagnosis of an autism spectrum disorder. The Scales of Independent Behaviour– Revised (SIB; Bruininks et al., 1996) were used to assess adaptive function. Questions addressed physical characteristics, such as the presence of high cholesterol, high blood pressure, diabetes and any sensory or physical disability in the person with ID, and the person’s height and weight. Respondents were also asked to list all current medications taken by the person with ID, including over-the-counter medications, and to provide details of the dose, frequency and length of medication use. Respondents were asked to provide details about any psychiatric or neurological diagnoses and the Developmental Behaviour Checklist for Adults (DBC-A). Diagnosis was classified as disorders for which there was a primary or secondary indication for any of the included CNS medications: schizophrenia or psychotic disorder, depression, anxiety and bipolar disorder as a psychiatric diagnoses, and epilepsy or seizure disorder and Parkinson’s disease as neurological diagnoses. The DBC-A is a 107-item carer-report checklist designed to assess emotional and behavioural disturbance in people with ID aged over 18 years, with total scores above 51 indicative of clinically significant levels of psychopathology (Mohr et al., 2011). Additionally, six analytically derived subscales can be scored: disruptive behaviours, communication and anxiety disturbance, self-absorption, antisocial, depression and social relating (Einfeld and Tonge, 2002; Mohr et al., 2005).
The study was carried out in accordance with the Declaration of Helsinki and was approved by the Human Research Ethics Committees of The University of New South Wales, Monash University and La Trobe University. When appropriate, written consent for the study was obtained from the person with ID. Otherwise, written consent by proxy was obtained from the person’s legal guardian or closest relative, with verbal consent obtained from the person with ID w herever possible. In Wave 1 of the Successful Ageing in Intellectual Disability (SAge-ID) Study, 118 participants with ID were recruited from areas within metro Sydney (Randwick, Botany Bay, Rockdale, Waverley, Woollahra, City of Sydney, Leichhardt, Marrickville, Ashfield, Burwood, Strathfield, Canterbury, Hurstville, Kogarah, Canada Bay, Sutherland Shire, Campbelltown, Camden, Liverpool, Fairfield and Bankstown), Illawarra and Shoalhaven areas in New South Wales (NSW) and the Loddon Mallee region of Victoria, Australia. The expected size of the people with ID over the age of 40 in our NSW catchment was expected to be 3350, based on the Department of Social Services (formally Department of Families, Housing, Community Services and Indigenous Affairs) estimate of the number of people receiving a disability pension with a primary medical condition of ID in these areas (Department of Families, Housing, Community Services and Indigenous Affairs, Disability support pensioners with primary medical condition of intellectual/learning by gender and selected LGAs – September Quarter 2012, 23 April 2013, personal communication). Multiple recruitment strategies were employed: (1) mail out to eligible participants via the databases of government disability service providers (Ageing, Disability and Home Care in NSW and Department of Human Services in Victoria); (2) direct approach to community group homes; (3) direct approach to hostels and aged care facilities; (4) mail-out and newsletter promotion through local carer support organisations, respite services and assisted employment services and (5) mail out to general practitioners (GPs) and psychiatrists. After the return of expression of interest forms, potential participants and carers were contacted. Following explanation of the study, assessment of inclusion/exclusion criteria and verbal consent, people with ID and their primary carers were posted participant information and consent forms along with a baseline questionnaire to complete. Participants were included in the study if they had ID ranging from mild to profound, were aged above 40 years and had an informant who knew them well and agreed to complete a questionnaire. Exclusion criteria included terminal illness and current residence in a correctional facility. Of the recruited participants, 114 with available medication data comprised the sample for this analysis. The other four persons were excluded because medication data were missing.
Data analysis A researcher trained in pharmacy (K.M.C.) reviewed all data to identify CNS medications and grouped them into categories according to MIMS Annual (2009). According to this system, medication Category 3 represents the agents for the CNS, which are further subcategorised as sedatives/ hypnotics (3a), anti-anxiety agents (3b), antipsychotic agents (3c), antidepressants (3d), CNS stimulants (3e), movement disorder medications (3f), anticonvulsants (3g) and anti-emetics and anti-nauseants (3h). Anti-emetics and anti-nauseants were excluded from analysis as it was not relevant to our study question. Once the medications were coded, a psychiatrist (J.N.T.) examined all CNS medications Australian & New Zealand Journal of Psychiatry
Downloaded from anp.sagepub.com at University of Otago Library on November 10, 2015
4 and reported diagnoses to determine whether a condition was present for which the CNS medication could be considered either a first- or second-line treatment according to standard clinical practice. For this study, CNS medication polypharmacy was defined as current use of more than one CNS medication and multi-class polypharmacy was defined as current use of more than one class of CNS medication. Medications used pro re nata (PRN) were included. Data were analysed using SPSS for Windows 22.0 (SPSS Inc., Chicago, IL, USA). Descriptive statistics were obtained for the sample for demographic characteristics and use of medication. To describe adaptive behaviour, standard scores for the SIB-R broad independence subscale were grouped into the following categories: 0.05 for all analyses). In comparison with the nonmedicated group, the medicated group had a significantly higher proportion of epilepsy or seizure disorder (χ2(1) = 22.5, p
ANP0010.1177/0004867415587951ANZJP ArticlesChitty et al.
Research
Central nervous system medication use in older adults with intellectual disability: Results from the successful ageing in intellectual disability study
Australian & New Zealand Journal of Psychiatry 1–11 DOI: 10.1177/0004867415587951 © The Royal Australian and New Zealand College of Psychiatrists 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav anp.sagepub.com
Kate M Chitty1, Elizabeth Evans1, Jennifer J Torr2, Teresa Iacono3, Henry Brodaty4,5,6, Perminder Sachdev4,7 and Julian N Trollor1,4
Abstract Objective: Information on the rates and predictors of polypharmacy of central nervous system medication in older people with intellectual disability is limited, despite the increased life expectancy of this group. This study examined central nervous system medication use in an older sample of people with intellectual disability. Methods: Data regarding demographics, psychiatric diagnoses and current medications were collected as part of a larger survey completed by carers of people with intellectual disability over the age of 40 years. Recruitment occurred predominantly via disability services across different urban and rural locations in New South Wales and Victoria. Medications were coded according to the Monthly Index of Medical Specialties central nervous system medication categories, including sedatives/hypnotics, anti-anxiety agents, antipsychotics, antidepressants, central nervous system stimulants, movement disorder medications and anticonvulsants. The Developmental Behaviour Checklist for Adults was used to assess behaviour. Results: Data were available for 114 people with intellectual disability. In all, 62.3% of the sample was prescribed a central nervous system medication, with 47.4% taking more than one. Of those who were medicated, 46.5% had a neurological diagnosis (a seizure disorder or Parkinson’s disease) and 45.1% had a psychiatric diagnosis (an affective or psychotic disorder). Linear regression revealed that polypharmacy was predicted by the presence of neurological and psychiatric diagnosis, higher Developmental Behaviour Checklist for Adults scores and male gender. Conclusion: This study is the first to focus on central nervous system medication in an older sample with intellectual disability. The findings are in line with the wider literature in younger people, showing a high degree of prescription and polypharmacy. Within the sample, there seems to be adequate rationale for central nervous system medication prescription. Although these data do not indicate non-adherence to guidelines for prescribing in intellectual disability, the high rate of polypharmacy and its relationship to Developmental Behaviour Checklist for Adults scores reiterate the importance of continued medication review in older people with intellectual disability. Keywords Intellectual disability, challenging behaviour, central nervous system medication, polypharmacy
1Department
of Developmental Disability Neuropsychiatry, UNSW Australia, Sydney, NSW, Australia for Developmental Disability Health, Monash University, Notting Hill, VIC, Australia 3La Trobe Rural Health School, La Trobe University, Bendigo, VIC, Australia 4Centre for Healthy Brain Ageing, UNSW Australia, Sydney, NSW, Australia 5Dementia Collaborative Research Centre, UNSW Australia, Sydney, NSW, Australia 6Academic Department for Old Age Psychiatry, Prince of Wales Hospital, Randwick, NSW, Australia 7Neuropsychiatric Institute, Prince of Wales Hospital, Randwick, NSW, Australia 2Centre
Corresponding author: Julian N Trollor, Department of Developmental Disability Neuropsychiatry, UNSW Australia, 34 Botany St, UNSW, NSW 2052, Australia. Email: [email protected]
Australian & New Zealand Journal of Psychiatry
Downloaded from anp.sagepub.com at University of Otago Library on November 10, 2015
2
ANZJP Articles
Introduction The prescription rates of central nervous system (CNS) medications to people with intellectual disability (ID) far exceed those within the general population. During 2011, within the Australian general population around 10% of people aged 45–54 years had accessed a CNS medication, increasing to around 25% in those aged 75 years and over – the largest rate across all age groups (ABS, 2011). In comparison, rates of CNS medication use are as high as 60% in adults with ID (Sachdev, 1991; Tsiouris et al., 2013), with limited representation within these samples of those aged 45 years and over. International studies also consistently report high rates of CNS medication polypharmacy (defined as more than one CNS medications) in ID, particularly of antipsychotics and anticonvulsants (Doan et al., 2013, 2014; Edelsohn et al., 2014; Hill et al., 1985; Sachdev, 1991; Thomas et al., 2010; Tsiouris et al., 2013). These findings raise concerns given the common adverse effects of these medications, which, especially in people with ID, can further exacerbate physical, mental, neurological and behavioural issues and markedly affect the quality of life (Allen, 2008; Matson et al., 2003; Thomas et al., 2010). Indeed, polypharmacy of CNS medication (as defined by the Monthly Index of Medical Specialties [MIMS]) in people with ID has been associated with an increased susceptibility to these side effects (Habetaler et al., 2014; Mahan et al., 2010). Compared with the general population, people with ID have been found to have higher rates of psychiatric diagnosis, especially psychotic and affective disorders (Cooper et al., 2007) and neurological diagnoses, especially seizure disorders (Bowley and Kerr, 2000; McGrother et al., 2006; Santosh and Baird, 1999). The high prevalence of these diagnoses indeed warrants CNS medication use; however, studies have shown that CNS medications in people with ID are commonly associated with treatment of challenging behaviours (McGillivray and McCabe, 2004; Matson and Neal, 2009). Challenging behaviours are defined as Culturally abnormal behaviours of such an intensity, frequency or duration that the physical safety of the person or others is likely to be placed in serious jeopardy or behaviour which is likely to seriously limit use of or result in the person being denied access to ordinary community facilities. (Emerson, 1995)
In a large Dutch study (n = 2373), about one-third of adults with ID were on an antipsychotic medication: for almost 60% of participants it was prescribed for challenging behaviours, with only 22% having a diagnosed psychiatric disorder and the remaining 18% with no reason specified for the CNS medication use (De Kuijper et al., 2010). Fleming et al. (1996) found that 69% of their sample (n = 118) was receiving CNS medication for challenging behaviour, whereas only 8% had a psychiatric diagnosis
(Fleming et al., 1996). Similarly, in a more recent Australian study of 117 adults with ID, antipsychotics were the most commonly prescribed medication class, and the presence of challenging behaviours and a psychiatric illness was significant predictors of their use (Doan et al., 2013). Prescription of CNS medication for challenging behaviour in the absence of a psychiatric diagnosis lacks consistent evidence to support its use (Deb and Unwin, 2007; Thomas et al., 2010; Tsiouris et al., 2013; Tyrer et al., 2009). This practice has occurred at least partly in response to the frequent occurrence of challenging behaviour in the ID population (Cooper et al., 2007), often presenting as non-specific symptoms requiring comprehensive multidisciplinary assessment and targeted intervention (WPA (SPID), 2010). Furthermore, impairments in communication and conceptual thought in ID present difficulties for psychiatric assessment and diagnosis and can lead to missed diagnosis and misdiagnosis (Torr, 2013). A recent Australian commissioned report recommended that medications should be kept to a minimum, with a review for adverse effects and efficacy conducted after 3–4 months and be removed from the treatment plan as safely and as soon as possible (Thomas et al., 2010). There is limited research into prescription of CNS medications for older people with ID, despite the increased life expectancy in this group (Patja et al., 2000; Torr and Davis, 2007) and a dearth of evidence available to inform policy and practice. A study that has preliminarily addressed this issue indicated that CNS medication appears particularly prevalent in the oldest age bracket, with 51% of participants aged 47 years and over on a psychotropic medication (Doan et al., 2013). Pary (1993) noted that rates of CNS medications increase with age from the 20–39 year age bracket to those over 55 years. This evidence is supported by reports indicating that once people with ID are placed on CNS medication, they are often continued with that prescription indefinitely without review (Thomas et al., 2010). The potential for polypharmacy in older adults is perhaps exacerbated by increased comorbidities. Compared with the general population, people with ID are at increased risk of a range of age-related health disorders, including frailty (Evenhuis et al., 2012), seizure disorders (McCarron et al., 2014), multimorbidity (Hermans and Evenhuis, 2014) and dementia (Cooper, 1997; for a review, see Evans et al., 2013). Given their multiple risk factors for medication side effects, the issue of medication use patterns in elders with ID warrants attention. The aim of this study was to examine CNS medication use in an Australian sample of older people with ID, with a particular focus on predictors of polypharmacy. We hypothesised that there would be a high rate of CNS medication use and polypharmacy among our older sample. We also hypothesised that challenging behaviours and psychiatric or neurological diagnoses would be significant predictors of CNS medication polypharmacy.
Australian & New Zealand Journal of Psychiatry Downloaded from anp.sagepub.com at University of Otago Library on November 10, 2015
3
Chitty et al.
Methods
Measures
Participants
For this analysis, we used baseline questionnaire data from the SAge-ID study. An informant (a family member, paid carer or friend) completed a questionnaire about the person with ID, including detailed structured family history, adaptive behaviour, challenging behaviour, medical and psychiatric history, medication use, lifetime and current levels of physical activity, leisure/mental activity, social activity and occupational activity. The questionnaire took approximately 2 hours to complete. Specifically, the questionnaire included items regarding the person with ID’s age, gender, living status, known causes of ID (if any) and lifetime diagnosis of an autism spectrum disorder. The Scales of Independent Behaviour– Revised (SIB; Bruininks et al., 1996) were used to assess adaptive function. Questions addressed physical characteristics, such as the presence of high cholesterol, high blood pressure, diabetes and any sensory or physical disability in the person with ID, and the person’s height and weight. Respondents were also asked to list all current medications taken by the person with ID, including over-the-counter medications, and to provide details of the dose, frequency and length of medication use. Respondents were asked to provide details about any psychiatric or neurological diagnoses and the Developmental Behaviour Checklist for Adults (DBC-A). Diagnosis was classified as disorders for which there was a primary or secondary indication for any of the included CNS medications: schizophrenia or psychotic disorder, depression, anxiety and bipolar disorder as a psychiatric diagnoses, and epilepsy or seizure disorder and Parkinson’s disease as neurological diagnoses. The DBC-A is a 107-item carer-report checklist designed to assess emotional and behavioural disturbance in people with ID aged over 18 years, with total scores above 51 indicative of clinically significant levels of psychopathology (Mohr et al., 2011). Additionally, six analytically derived subscales can be scored: disruptive behaviours, communication and anxiety disturbance, self-absorption, antisocial, depression and social relating (Einfeld and Tonge, 2002; Mohr et al., 2005).
The study was carried out in accordance with the Declaration of Helsinki and was approved by the Human Research Ethics Committees of The University of New South Wales, Monash University and La Trobe University. When appropriate, written consent for the study was obtained from the person with ID. Otherwise, written consent by proxy was obtained from the person’s legal guardian or closest relative, with verbal consent obtained from the person with ID w herever possible. In Wave 1 of the Successful Ageing in Intellectual Disability (SAge-ID) Study, 118 participants with ID were recruited from areas within metro Sydney (Randwick, Botany Bay, Rockdale, Waverley, Woollahra, City of Sydney, Leichhardt, Marrickville, Ashfield, Burwood, Strathfield, Canterbury, Hurstville, Kogarah, Canada Bay, Sutherland Shire, Campbelltown, Camden, Liverpool, Fairfield and Bankstown), Illawarra and Shoalhaven areas in New South Wales (NSW) and the Loddon Mallee region of Victoria, Australia. The expected size of the people with ID over the age of 40 in our NSW catchment was expected to be 3350, based on the Department of Social Services (formally Department of Families, Housing, Community Services and Indigenous Affairs) estimate of the number of people receiving a disability pension with a primary medical condition of ID in these areas (Department of Families, Housing, Community Services and Indigenous Affairs, Disability support pensioners with primary medical condition of intellectual/learning by gender and selected LGAs – September Quarter 2012, 23 April 2013, personal communication). Multiple recruitment strategies were employed: (1) mail out to eligible participants via the databases of government disability service providers (Ageing, Disability and Home Care in NSW and Department of Human Services in Victoria); (2) direct approach to community group homes; (3) direct approach to hostels and aged care facilities; (4) mail-out and newsletter promotion through local carer support organisations, respite services and assisted employment services and (5) mail out to general practitioners (GPs) and psychiatrists. After the return of expression of interest forms, potential participants and carers were contacted. Following explanation of the study, assessment of inclusion/exclusion criteria and verbal consent, people with ID and their primary carers were posted participant information and consent forms along with a baseline questionnaire to complete. Participants were included in the study if they had ID ranging from mild to profound, were aged above 40 years and had an informant who knew them well and agreed to complete a questionnaire. Exclusion criteria included terminal illness and current residence in a correctional facility. Of the recruited participants, 114 with available medication data comprised the sample for this analysis. The other four persons were excluded because medication data were missing.
Data analysis A researcher trained in pharmacy (K.M.C.) reviewed all data to identify CNS medications and grouped them into categories according to MIMS Annual (2009). According to this system, medication Category 3 represents the agents for the CNS, which are further subcategorised as sedatives/ hypnotics (3a), anti-anxiety agents (3b), antipsychotic agents (3c), antidepressants (3d), CNS stimulants (3e), movement disorder medications (3f), anticonvulsants (3g) and anti-emetics and anti-nauseants (3h). Anti-emetics and anti-nauseants were excluded from analysis as it was not relevant to our study question. Once the medications were coded, a psychiatrist (J.N.T.) examined all CNS medications Australian & New Zealand Journal of Psychiatry
Downloaded from anp.sagepub.com at University of Otago Library on November 10, 2015
4 and reported diagnoses to determine whether a condition was present for which the CNS medication could be considered either a first- or second-line treatment according to standard clinical practice. For this study, CNS medication polypharmacy was defined as current use of more than one CNS medication and multi-class polypharmacy was defined as current use of more than one class of CNS medication. Medications used pro re nata (PRN) were included. Data were analysed using SPSS for Windows 22.0 (SPSS Inc., Chicago, IL, USA). Descriptive statistics were obtained for the sample for demographic characteristics and use of medication. To describe adaptive behaviour, standard scores for the SIB-R broad independence subscale were grouped into the following categories: 0.05 for all analyses). In comparison with the nonmedicated group, the medicated group had a significantly higher proportion of epilepsy or seizure disorder (χ2(1) = 22.5, p
