University of Manchester, Psychiatry Research Group, School of Community Based Medicine, Manchester, UK
University of Manchester, Psychiatry Research Group, School of Community Based Medicine, Manchester, UK, and Radboud University Nijmegen Medical Centre, Department of Psychiatry, Nijmegen, The Netherlands
University of Manchester, Centre for Suicide Prevention, Manchester, UK
University of Manchester, Psychiatry Research Group, School of Community Based Medicine, Manchester, UK
University of Manchester, Centre for Suicide Prevention, Manchester, UK.
Correspondence: Dr N. Purandare, Room 3.316, Psychiatry Research Group, School of Community Based Medicine, University of Manchester, University Place (3rd Floor East), Oxford Road, Manchester M13 9PL, UK. Email: nitin.purandare{at}manchester.ac.uk
None. Funding detailed in Acknowledgements.
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Knowledge of suicide in people with dementia is limited to small case series.
Aims
To describe behavioural, clinical and care characteristics of people with dementia who died by suicide.
Method
All dementia cases (n=118) from a 9-year national clinical survey of suicides in England and Wales (n=11 512) were compared with age- and gender-matched non-dementia cases (control group) (n=492) by conditional logistic regression.
Results
The most common method of suicide in patients with dementia was self-poisoning, followed by drowning and hanging, the latter being less frequent than in controls. In contrast to controls, significantly fewer suicides occurred within 1 year of diagnosis in patients with dementia. Patients with dementia were also less likely to have a history of self-harm, psychiatric symptoms and previous psychiatric admissions.
Conclusions
Known indicators of suicide risk are found less frequently in dementia suicide cases than non-dementia suicide cases. Further research should clarify whether suicide in dementia is a response to worsening dementia or an underappreciation of psychiatric symptoms by clinicians.
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Dementia is one of the major healthcare problems in later life, affecting 24 million people worldwide.7 Although high rates of psychiatric symptoms during the course of illness have been reported,8 the risk of suicide in people with dementia is generally considered low.9,10 Empirical data on suicide in dementia are scarce and primarily based on case reports (e.g. Rhode et al11). In a recent summary of those case reports, it has been suggested that early stage of dementia, male gender, high educational level, professional occupation, retention of insight, depressive features post-dating the onset of dementia, suicidal ideation and access to firearms might be risk factors for completed suicide in dementia.9 Furthermore, some studies have reported significantly more Alzheimer's pathology in the brains of older suicide victims compared with age- and gender-matched controls who died naturally,12 although findings have not been consistent.13
The National Confidential Inquiry into Suicide and Homicide by People with Mental Illness collects data on all those who die by suicide within 12 months of last contact with mental health services of the National Health Service (NHS) in the UK.14 It currently holds data on 11 512 people aged 10 years and above who died by suicide in the period April 1996 to December 2004 and offers a unique opportunity to examine suicide in dementia in more detail. Our objectives were to describe the behavioural, clinical and care characteristics of patients with dementia who died by suicide, and to compare them with age- and gender-matched controls who died by suicide and who did not have clinical diagnosis of dementia.
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Comprehensive national sample
Information on all deaths in England and Wales receiving a suicide or an
open verdict at coroner's inquest was obtained from the Office for National
Statistics. The cases presented here consist of suicides registered by the
Office for National Statistics from 1 April 1996 until 31 December 2004. In
the first 3 years of the study, this information was cross-checked against
equivalent data from health authorities in England and Wales; inconsistencies
were rare. Open verdicts, recorded as deaths from undetermined external cause,
are often reached in cases of suicide in the UK. Open verdicts are
conventionally included in research on suicide and in official suicide
statistics.16–18
In this study, we adopted this convention and included open (ICD–10
codes Y10–Y34, excluding Y33.9 (verdict pending) and Y87.2 (sequelae of
events of undetermined intent)) as well as suicide (ICD–10 Codes
X60–X84 and Y87.0)
verdicts.19
Identification of mental health service contact and collection of clinical data
Identifying details on each individual who had died by suicide were
submitted to the main hospital and community NHS trusts who provided mental
health services to people living in the deceased's district of residence. When
NHS records showed that contact had occurred in the 12 months before the
suicide, the person became an `Inquiry case'. For each Inquiry case, the
consultant psychiatrist was sent a questionnaire and asked to complete it
based on their knowledge of the patient, psychiatry case notes, and in
discussion with other members of the mental health team. The questionnaire
consisted of sections covering social/demographic characteristics, clinical
history, details of suicide, aspects of care, details of final contact with
mental health services and clinicians' views on suicide prevention. Clinicians
were asked for an ICD–10 primary diagnosis and also any ICD–10
secondary
diagnoses.19 The
social and clinical items reflected many of the most frequently reported risk
factors for suicide. The majority of items were factual but some (for example,
adherence to treatment) were based on the judgements of clinicians.
Identification of patients with dementia and selection of controls
Based on the information provided by the responsible consultant
psychiatrist, we identified all patients with an ICD–10 diagnosis of
dementia.19 A total
of 118 patients with dementia were identified. For each individual with
dementia, we extracted four gender-matched suicide cases of patients without a
diagnosis of dementia (controls) nearest in age to the dementia patients
(n=472). This selection was masked, i.e. we were unaware of the
behavioural, clinical and care characteristics of these controls. All controls
were individually matched for gender and 462/472 (98%) for age within 2 years
of the index case (3-year difference for seven cases, 5-year difference for
two cases and 6-year difference for one case).
Statistical analysis
All data are presented as absolute numbers and percentages within groups.
If an item of information was not known for a case, the case was removed from
the analysis of that item; the denominator in all estimates is therefore the
number of valid cases for the item. Differences between cases and controls
were tested by univariate conditional logistic regression analyses, using
Intercooled Stata 9.0 for Windows. As the study was mainly exploratory, main
findings are presented as odds ratios (OR) including 95% confidence intervals
(CI). Acknowledging heterogeneity in the cases of dementia, we also performed
subgroup analyses. The following subgroups were defined: (a) patients with
dementia aged 65 years and over; and (b) all dementia cases excluding those in
which the individual had a comorbid diagnosis of alcohol dependence and/or
schizophrenia and other delusional disorders. Dementia associated with alcohol
dependence or schizophrenia and related disorders is thought to be
qualitatively different from dementia in older people caused by
neurodegenerative and/or cerebrovascular processes (e.g. Alzheimer's disease,
vascular dementia and dementia with Lewy
bodies).20 Patients
with dementia under the age of 65 years were not selected for subgroup
analyses as we anticipated small numbers.
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Behavioural, clinical and care characteristics of the dementia group
The 118 patients who had died by suicide and had a clinical diagnosis of
dementia had a median age of 75 years (range 32–95) and 63 (53%) were
male. The sample was predominantly White, including only 5 (4%) individuals
from an ethnic minority group. Furthermore, 36 (32%) individuals were married
and 58 (49%) lived alone at the time of suicide.
Online Table DS1 describes behavioural, clinical and care characteristics of the dementia group as a whole, and by predefined subgroups. For 91 (80%) of the group, the last contact with services was routine or non-urgent, and for 57 (50%) it occurred in patients' homes. A care-coordinator was allocated in 84 (81%) cases and 47 (40%) individuals were on an enhanced care programme approach (a form of enhanced aftercare indicative of clinical complexity and involvement of at least two members of a multidisciplinary team with different professional backgrounds, usually a community psychiatry nurse and a psychiatrist). The time between last contact and the suicide was less than 1 week for 50 (44%) individuals, and less than 24 h for 18 (16%). A further 29 (25%) individuals had their last contact between 1 and 4 weeks before suicide, 13 (11%) between 5 and 13 weeks, and 23 (20%) more than 3 months before. Evidence of psychiatric symptoms at the last contact was noted for 41 (35%) individuals, most often depressive illness (n=18, 16%), hopelessness (n=10, 9%) and delusions or hallucinations (n=8, 7%). In four patients (4%) suicidal ideation was recorded at the last contact. A deterioration in physical health was noted for 27 (24%) patients.
A total of 26 individuals who had died by suicide and had a diagnosis of dementia were aged below 65 years, and half of this younger subgroup (n=13, 50%) had a history of alcohol and/or drug misuse, including 6 (23%) with a diagnosis of alcohol dependence. As shown in online Table DS1, this subgroup had more involved psychiatric histories and received more intense psychiatric care.
Method of suicide
Similar to the control group, self-poisoning was the most common method of
suicide in the dementia group, accounting for almost a third of deaths
(Table 1). The substance used
was highly variable, most often being analgesics (n=12: paracetamol,
n=4; codeine-containing preparations and other opiate analgesics,
n=4; other analgesics, n=4), psychotropic drugs
(n=4, all different classes), or other poisons such as weed killer
(n=4). All other substances were used only once. After
self-poisoning, drowning (19%) and hanging (17%) were the second and third
most common methods of suicide among patients in the dementia group. The main
analysis showed that hanging was used significantly less often by those in the
dementia group compared with controls. Three suicides in the dementia group
were part of a suicide pact.
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Table 1 Method of suicide in patients with dementia compared with controls
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Comparison with the non-dementia group
Patients with dementia who died by suicide were compared with their matched
controls on all variables presented in online Table DS1. All demographic
characteristics were similar for those in the dementia group and their age-
and gender-matched controls (P>0.43). In
Table 2, behavioural, clinical
and care variables that were significantly different in patients with dementia
and their controls are presented. With respect to psychiatric history,
patients with dementia less often died by suicide within 1 year of diagnosis,
were less often prescribed antidepressants, and were less likely to have a
history of self-harm. Although the main analysis suggests that patients with
dementia were more likely to have a history of violence (12% v. 6%,
P=0.018), the difference was quite small and was not replicated in
the two subgroup analyses (Table
2). In line with these findings, patients with dementia had fewer
psychiatric admissions and were also less likely to die by suicide while
psychiatric in-patients. Significantly fewer psychiatric symptoms were
reported during the last contact with a mental health service professional in
patients with dementia compared with their matched controls, of which
emotional problems (31% v. 16%, P=0.002) and depressive
symptoms (40% v. 16%, P<0.001) reached statistical
significance. Life events within 3 months prior to suicide were evaluated
systematically in 14 different categories (e.g. interpersonal problems with
significant others, financial problems, victim of violence). The frequency of
all different life events was similar in patients with dementia and controls,
including `own physical health problems' which was the most often reported
life event in both groups (15% v. 17%, P=0.82).
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Table 2 Behavioural, clinical and characteristics of patients with dementia that
differed significantly from their controls at time of suicide
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The methods of suicide used by patients with dementia were comparable to those used by controls. Moreover, we did not find differences with respect to the classic risk factors for suicide in later life, such as physical illness and life events.10 Suicide in dementia, however, was characterised by fewer behavioural and clinical indicators of suicide risk compared with controls in our study, as well as when compared with previous studies on older suicide victims in general.22 The individuals with dementia who died by suicide were significantly less likely to have a history of self-harm or a history of psychiatric admissions. At the last contact prior to suicide, psychiatric symptoms were less likely to be noted in the dementia group than in the control group. It may be that in people with dementia, the cognitions or concerns about the progression of dementia are more important determinants of suicide. Alternatively, psychiatric symptoms, especially depressive symptoms, may be underrecognised in patients with dementia or wrongly attributed to being core symptoms of dementia because of overlap between depression and dementia.23 This latter explanation is especially relevant as depressive illness is the most important risk factor for suicide in older adults, with a population attributable risk of up to 74%.24 In addition, depressive illness may negatively mediate the effect of physical illness.9
Interestingly, the time since diagnosis in the dementia group was more often between 1 and 5 years compared with patients who had other psychiatric diagnoses, which is in line with results of a retrospective study of suicide in dementia cases admitted to a psychiatric hospital.25 This time period corresponds to the first two-thirds of the disease process, with a median survival time of 10.5 years from onset and 5.7 years from diagnosis,26 which significantly decreases with advancing age.27 The predominance of suicide in the first half of the dementia process might be explained by significantly less interference of cognitive deficits with the planning and executing of the suicide act at this stage.28,29 Moreover, depressive symptoms, which may have been underestimated in our sample, predominate the initial stage of the dementia process, whereas the latter stages are more dominated by apathy.29,30 Importantly, our data show a very low prevalence of suicide in the first 12 months after dementia has been diagnosed. This finding may indicate that disclosure of diagnosis, although it might evoke suicidal thoughts, is not a risk factor as sometimes suggested.31 Our results are most consistent with the view that the risk for suicide is highest at the stage of the disease process where patients experience increasing difficulties in daily living activities due to their dementia, but still have a preservation of insight into ongoing and impending cognitive deterioration.32 This point of view contrasts with suicides in other psychiatric disorders in which lack of insight is generally a risk factor for suicide.15
Study limitations
Although the large size of the database used in this study and high
absolute number of dementia suicide cases enhances its inferential value, the
findings of this study need to be interpreted in the context of certain
methodological issues. First, this study is a survey of the clinical
circumstances preceding suicide, and we are unable to make causal inferences.
A control group of patients with dementia who had not died by suicide would
have been relevant for identification of suicide risk factors specific for
dementia. Controls were mental health patients who died by suicide with a
diagnosis other than dementia. Therefore, the differences we observed could
simply be due to differences between diagnostic groups (rather than
differences in suicide risk). As depression (and rarely other psychiatric
illnesses) may precede dementia, it is possible that some of the controls may
in fact have undiagnosed early
dementia.33 This
raises the possibility that that observed differences between dementia
suicides and the control group of non-dementia suicides may be underestimated.
Known risk factors for suicide in later life (i.e. male gender and older age,
could not be examined because of matched
analyses).10,34
Second, the generalisability of our findings is limited to patients with
dementia in contact with mental health services, most likely patients with
dementia with significant behavioural and psychological symptoms. Therefore,
suicides in patients with `uncomplicated' dementia or those who are not
receiving treatments to enhance cognition may be under-represented in this
sample. Such a bias towards patients with dementia with behavioral
difficulties or psychiatric comorbidity make the findings in relation to less
symptomatology and comorbidity more remarkable. Moreover, this may also
explain the low number of ethnic minorities, as elderly suicide victims from
ethnic minorities are less likely to be in contact with psychiatric
services.35 Third,
the clinicians who provided the information by filling out the study
questionnaires were not masked to patient outcome and this may have affected
their response to certain questions, for example, the preventability of
suicide in their patient. However, this will not affect the comparison between
cases and controls, and the accuracy of the Inquiry questionnaire has been
shown to be
good.14
We used the wider definition of suicide that included both suicide and deaths of undetermined intent. This is the standard definition that is used in official statistics and previous research. Excluding open verdicts may underestimate the number of actual suicide deaths by 50%.18 However, the number of open verdicts was much higher in the dementia group than the control group in this study – why might this be? A study of all suicide and open verdicts over a 10-year period in one coroner's court found that the factors which most reliably distinguished suicide from open verdicts included method of death (hanging and death from car exhaust poisoning more common; drowning and falling from a height less common) and presence of a suicide note. A small study of deaths in individuals aged 65 years found that evidence of suicidal intent, psychiatric history and method of death distinguished suicide and open verdicts.36 In our study, the cases with dementia included a lower proportion of hanging deaths and a higher proportion of drowning deaths than controls. Those with dementia were less likely to have a significant psychiatric history. Individuals with dementia who died by suicide were also presumably less likely than those with other diagnosis who died by suicide to indicate suicidal intent or to write a suicide note, although we did not investigate these factors directly.
Clinical implications
The antecedents and clinical characteristics of patients with dementia who
die by suicide differ from age- and gender-matched suicide victims with other
psychiatric diagnoses. The low prevalence of suicide in dementia combined with
fewer long-standing psychiatric problems, as well as fewer psychiatric
symptoms just before death compared with controls, means that identifying
people with dementia who are at risk of suicide remains a significant clinical
challenge. Patients may be at particular risk 1–5 years after diagnosis;
during this period, suicidal thoughts could be openly discussed with patients
and their families. This may help improve underrecognition and undertreatment
of psychiatric comorbidity such as depression.
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C. Haw Dementia: suicide by drowning The British Journal of Psychiatry, June 1, 2009; 194(6): 563 - 564. [Full Text] [PDF] |
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E. Salib Dementia: suicide by drowning The British Journal of Psychiatry, June 1, 2009; 194(6): 562 - 563. [Full Text] [PDF] |
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