Background: Homicide by older offenders is rare and devastating. It likely occurs due to a complex interaction of personal, social, and environmental factors. Dementia is a progressive neurological condition which may amplify behavioural disturbances such as aggression. This systematic review aims to evaluate the factors associated with homicide committed by people with dementia in order to inform clinical practice. Summary: MEDLINE, PsychINFO, Embase, and PubMed databases were searched in accordance with PRISMA guidelines for empirical studies examining the characteristics and circumstances of people with dementia who committed homicides. Data on factors associated with the homicide were extracted and the quality of each study rated using standardized criteria. A total of 499 papers were screened and thirteen studies met the inclusion criteria. Study design included case reports (seven studies), case series (four studies), and two retrospective cohort studies, indicative of low levels of evidence. Sample sizes were 1–70. Study findings were predominantly descriptive. Quality ratings ranged from 50 to 100%. Factors associated with disinhibition such as dysexecutive syndrome, alcohol use, and delirium may predispose to severe impulsive aggression. Psychosis and personality pathology appeared to influence targeted assaults resulting in homicide by people with dementia. Victim vulnerability was also a key element. Key Messages: The current evidence examining risk factors for homicide committed by people with dementia is limited. However, there are common characteristics reported in these descriptive studies including psychiatric factors and cognitive states causing disinhibition. Recommendations for clinical practice include early assessment of older people with dementia and changed behaviours to allow management of comorbidities and reversible risk factors, alongside education, and advice to carers (who may be targets of aggression). Specialized geriatric forensic psychiatry services and care settings should be developed.

The incidence of homicide by older offenders is unknown, but based on international data, it can be estimated at approximately ≤1% of all homicides [1-3]. Although this is a rare event, the outcome is devastating and rates may increase within the context of an ageing population [2, 4]. There are also particular challenges faced due to the complexity and costs of managing the physical and mental health needs of older offenders in the Correctional and Justice System [4-6]. Definitions of what constitutes an “older prisoner” are inconsistent across jurisdictions, varying between 45 and 65 years of age [7-9]. However, many consider that a typical prisoner has a physical health status 10 years older than their community counterpart [9-11]. This reflects the accelerated ageing that occurs in this population with early onset of disabilities and chronic diseases [11].

Worldwide, it is estimated that 50 million people have dementia with almost 10 million new cases every year [12]. There is an increasing burden on public health systems to manage Behavioural and Psychological Symptoms of Dementia, also known as changed behaviours [13, 14]. This may present as a dysexecutive syndrome, also termed frontal impairment, frontal lobe syndromes, or executive dysfunction within the literature [15]. The spectrum of behaviours ranges from agitation through to serious aggression and frequently affects family members, home carers, and staff or co-residents in nursing homes [16, 17]. Aggression in dementia is often multifactorial and may include associations with medical comorbidity, current mental state, and environmental aspects [14, 18]. Some overlap would be expected between risk factors for aggression in dementia and for homicide, which could be considered the most serious outcome of an assault [14, 16]. However, this has not been systematically examined to date.

Although homicide is a rare event [1, 6], better understanding of the concomitant factors associated with homicide committed by people with dementia may help inform clinical practice by highlighting which people warrant more urgent assessment, closer monitoring, or intervention [2, 14]. The purpose of this study is to evaluate the published literature reporting factors associated with completed homicide by older people (defined as ≥55 years) with dementia.

This systematic review was performed according to PRISMA guidelines.

Search Strategy

Electronic databases including MEDLINE (1946–June 2020), PsychINFO (1806–June 2020), Embase (1974–June 2020), and PubMed were searched using the combination of keywords “dementia AND (homicide OR murder)”. Searches were limited to articles in English. All titles and abstracts were screened for relevance. If the abstract was ambiguous or appeared likely to meet the inclusion criteria, the full text was reviewed. The reference lists of included publications were then hand searched for additional eligible studies.

Inclusion and Exclusion Criteria

An older person was defined as ≥55 years old, consistent with the Corrective Services NSW definition [19]. Each of the citations was examined to identify studies for inclusion if they (a) had patients ≥55 years at the time of the offence and had a diagnosis of major neurocognitive disorder/dementia; (b) the offence was completed homicide; (c) the article described empirical research of any design type or methodology (quantitative or qualitative studies). Case reports/series were eligible for inclusion if there was a detailed description of the case(s). Articles describing a broader aged cohort but which contained subgroup data on people aged ≥55 were included.

Articles were excluded if they were reviews or meta-analyses, commentaries, or from the grey literature. Studies which described people with dementia <55 years old or older adults within a broader aged cohort but without separate analysis of data for people ≥55 were excluded.

After removal of duplicate citations, the titles and abstracts were screened against inclusion criteria. Questions about appropriateness for inclusion were resolved by discussion among authors until consensus was reached.

Data Extraction

Full-text articles of relevant abstracts were obtained, with included studies independently reviewed and assessed for quality by all three authors. A meta-analysis was considered but not possible given the limited data available and the heterogeneity of the studies. A systematic review of included studies was undertaken with data extraction using a standardized form consisting of (1) study information (study design, key findings); (2) demographic data (setting, participant age and sex); (3) diagnosis of major neurocognitive disorder/dementia (method of diagnosis, subtype); (4) offender factors (comorbidity, history of aggression); (5) offence factors (method, relationship with victim, location); (6) quality analysis (assessment of methodological quality and noted limitations).

Assessment of Quality

The Alberta Heritage Foundation for Medical Research Standard Quality Assessment Criteria for quantitative research was used to score each included study (subsequently referred to here as Kmet, the first author) [20]. This scoring system provides a framework to assess the quality of studies with a range of methodological designs. The checklist of items included in the Kmet quality criteria enables evaluation of the research question, study design, participant selection, description of characteristics, random allocation and blinding, outcome measures, sample size, analytic methods, variance, confounding, results, and conclusion. A score from 0 to 2 is given for each relevant item (0 = No, 1 = Partial, 2 = Yes). Items which are not applicable to certain study designs such as random allocation and blinding in case reports/case series are marked N/A and the total possible score is consequently modified. The final score is derived by the total sum divided by the total possible sum. The rating for each study enables calculation of a percentage score with robustness of studies expressed by higher scores. While there is no accepted cutoff for quality ratings of Kmet scores, another systematic review regarded >80% as high quality [21]. Independent author quality ratings were compared and differences in scoring discussed and resolved to reach the final score.

Figure 1 details the PRISMA flowchart for study selection. Thirteen studies met the inclusion criteria [5, 16, 22-32]. The study information and key findings are further outlined in Table 1. Several studies utilized retrospective database searches to gather data from hospital, court, or police records. Study designs included two retrospective cohort studies [16, 24], four retrospective case series [5, 22, 23, 30] and seven case reports [25-29, 31, 32]. Sample sizes were 1–70. The study quality ratings ranged from 50 to 100%. Four studies were rated high quality (≥80%) [16, 22, 26, 29], an additional five rated good (≥70%) [24, 25, 28, 30, 31], and four were <70% (range 50–67%) [5, 23, 27, 32]. In one study [22], the detailed dataset was published separately [33], enabling relevant raw data to be extracted (i.e., subjects in the target age range of ≥55 years).

Table 1.

Summary of reviewed studies: characteristics of homicide offenders with dementia

Summary of reviewed studies: characteristics of homicide offenders with dementia
Summary of reviewed studies: characteristics of homicide offenders with dementia
Fig. 1.

PRISMA flow diagram. Results of the literature search. *This paper [22] had a separately reported dataset [33], and was thus counted as one study.

Fig. 1.

PRISMA flow diagram. Results of the literature search. *This paper [22] had a separately reported dataset [33], and was thus counted as one study.

Close modal

The key findings are outlined in Table 1. Most offenders were male (132/153, 86%). From those sampled in the community, the victim was a spouse in 62% of cases (79/128) [5, 22, 24, 25, 27-32]. For those in institutional settings, two case reports described the victim as another male resident [23, 26], while the retrospective cohort study found that risk of death from resident-resident aggression was twice as high for male residents compared with female (p = 0.05), despite victims of aggression being slightly more likely to be female (15/25, 53.6%) [16].

The type of dementia was not always specified or the method of diagnosis. However, ten studies utilized clinician assessment to make the dementia diagnosis [5, 22, 24-30, 32], with six including details of neuroimaging performed [22, 25-27, 29, 30]. The diagnosis of dementia was made postmortem in only one case [31]. Common factors emerged in these homicide offenders, including the type of dementia with the presence of dysexecutive syndrome, psychosis, alcohol use, personality pathology, victim vulnerability, and delirium. Given the nature of underlying comorbidity in homicide offenders with dementia, several studies highlighted the need for specialized assessment [5, 16, 22, 24, 25, 27, 28, 34] and care settings [5, 16, 22, 24, 26, 27].

This is the first systematic literature review examining factors associated with homicide by people with dementia. The majority of studies reviewed (9/13) [16, 22, 24-26, 28-31] had good or excellent quality ratings [20, 21]. However, the level of evidence was low in terms of study design, the highest being level 4 [35] comprising historical cohort studies [16, 24]. The majority of studies were case report/series (7/13) [25-29, 31, 32]. Given that homicide is a rare occurrence, the absence of large-scale studies and use of less methodologically robust study designs is perhaps unsurprising. While there are inherent limitations in case reports such as lack of generalizability and bias, this design remains valuable in gathering data on rare outcomes and generating hypotheses which may be useful to inform further research [36].

Common factors described as associated with disinhibition such as dysexecutive syndrome, alcohol use, and delirium may predispose to severe impulsive aggression. Psychosis and personality pathology appeared to influence targeted assaults resulting in homicide by people with dementia. Victim vulnerability is an important consideration when assessing and mitigating risks. Given the interplay between psychiatric and cognitive factors in homicide offenders with dementia, there should be consideration of specialized geriatric forensic psychiatry services [5, 16, 22, 24, 26, 27]. A lack of suitable accommodation was identified as a gap in existing management for people with dementia and aggression [5, 16, 22, 24, 26, 27] with long-term secure facilities likely required [5, 26].

Dementia Diagnosis

Dementia, also termed major neurocognitive disorder [37], is a progressive neurological condition which may include changed behaviour such as increased aggression. This review found that subtypes involving a dysexecutive syndrome appear related to homicide [22, 25, 33]. In the largest confirmed dataset of homicide by older people with dementia, a primary diagnosis of Frontotemporal Dementia was reported in 4/20 (20%) with a dysexecutive syndrome reported in a total of 9/20 (45%) of cases [33]. Despite the vast majority (if not all) of our gathered literature reporting impulsive acts rather than premeditation, it was surprising that the possibly key role of executive impairment was specifically highlighted in only one article [25]. When executive functioning is impaired, it affects the capacity for inhibition, processing of new information, and the cognitive flexibility to modify behaviour in response to environmental stimuli [38]. This is variably referred to in the literature as frontal impairment, dysexecutive syndrome, or executive dysfunction and usually reflects neurological impairment in the dorsolateral prefrontal and orbitofrontal cortices [15]. Some subtypes of dementia are specifically associated with behavioural dysregulation, for example, Frontotemporal Dementia with atrophy of these cortical areas [38, 39]. Additionally, dysexecutive syndrome appears to be frequently underestimated in Alzheimer’s disease and dementia of other types [38]. As the time frame of the publications encompassed 35 years, it is important to note the variation in diagnostic criteria and tools available over this period as classifications and knowledge has evolved [32]. Yet, the relationship between specific dementia types and violence leading to homicide remains unclear with further studies needed.

This review highlights the importance of systematic examination of cognitive function as part of a comprehensive clinical assessment of older homicide offenders, which does not appear to be current standard practice. It seems likely this results in underestimating the prevalence and contributory role of dementia in offenders, particularly regarding the diagnosis of dysexecutive syndrome which has been associated with aggression [5, 14, 40]. On the other hand, bedside cognitive tests (such as the Mini-Mental State Examination and Frontal Assessment Battery, validated screening tools in specific populations) were sometimes incorrectly referred to as diagnostic tools [25, 27, 29]. Some screening tools used in the studies, such as the Mini-Mental State Examination, do not detect dysexecutive syndrome [41], potentially missing important data. In one study, the authors were contacted to clarify that their term “cognitive disorder” included dementia [5]. In half of the studies, the diagnosis of dementia was made for the first time after the offence [25, 27-31]; indeed, sometimes homicide may be the earliest recognized manifestation of a patient’s dementia [25]. However, few papers provided evidence to exclude important differential diagnoses of depression and physical illness, which may alter cognition and thereby mimic dementia [18].

Dementia is usually diagnosed according to the criteria of either the International Classification of Diseases [42] or the Diagnostic and Statistical Manual [37]. Collateral information describing a progressive decline in cognition and function is fundamental to making a diagnosis [37, 42]. Given that institutionalization (whether this be in a health or correctional setting) has been linked to deterioration in cognition through sensory deprivation and social isolation [4, 25], this adds another layer of complexity with retrospective dementia diagnosis. Further, although dementia is primarily a clinical diagnosis, the lack of neuroimaging and possible diagnostic overshadowing was notable [43] and few studies (4/13) reported a collateral history being taken regarding cognition and function [27-29, 31]. Within the studies reviewed, only half included information on neuroimaging [22, 25-27, 29, 30] (excluding the single postmortem study) [31]. This highlights the need for appropriate and specialized assessment of older offenders in order to ensure appropriate diagnostic clarity.

Psychotic Phenomena

Psychosis emerged as a common clinical feature in cases of homicide by people with dementia, perhaps unsurprising given that psychotic symptoms are conceptualized within the syndrome of Behavioural and Psychological Symptoms of Dementia and occur in approximately 25% of people with dementia [18]. Various psychotic symptoms were reported including delusional jealousy [5, 27, 28, 33], a likely case of delusional misidentification attributed to prosopagnosia [25], and persecutory delusions [25, 30, 31]. Specific persecutory delusions towards the victim were noted, for example, beliefs that the victim was abusing, attacking, or stealing from the person with dementia [25, 30, 31]. In residential aged care settings, a high proportion (∼29%) of aggressive residents involved in altercations leading to a death had schizophrenia [16]. Persecutory beliefs regarding the victim may predispose to violent behaviour due to the perpetrator’s delusional reasoning [23, 34]. Thus, people with dementia with persecutory delusions regarding specific targets should raise particular concern. Given the high proportion of patients with cognitive impairment (CI) (of any severity) and psychosis, it has been suggested that all older offenders should undergo psychiatric assessment [5]. Similarly, when delusional jealousy (Othello Syndrome) is present, and especially when it occurs for the first time in old age, clinicians should hold a high index of suspicion regarding an undiagnosed dementia [44].

Alcohol Use

A range of alcohol use disorders were identified in older people with dementia committing homicide, including acute intoxication [24, 33], alcohol-related brain damage [5, 26, 33], and abuse/dependence [5, 24, 26]. Alcohol use may also influence other risk factors for homicide, such as CI and personality pathology. Only a third of the studies explored alcohol use [5, 22, 24, 26], despite longstanding recognition of the relationship between violence and acute alcohol intoxication [45]. In two cohorts, an association was made between alcohol use, homicide, and CI [22, 24], although in one cohort the exact proportion of people with dementia specifically was not quantified [24]. Strikingly, in one of these studies 80% of offenders were intoxicated with alcohol at the time of offence and over half of those aged 60 and older had a diagnosis of alcohol abuse/dependence [24]. Two case reports noted a history of alcohol use in older homicide offenders but did not consider its role in the homicide, including whether there was acute intoxication at the time of offence [27, 28].

Binge drinking is increasing in older people [46] and warrants greater attention for screening and management [24]. Alcohol use in older adults has been linked to social isolation; thus, the proximity of vulnerable victims – such as a frail spouse – may also increase risk [47]. Further, long-term use of alcohol is associated with dysexecutive syndrome, already identified in this review as a risk factor for homicide by people with dementia. Dysexecutive syndrome has also been linked with difficulty abstaining from alcohol [48], perpetuating risk despite cessation of use.

Antisocial Behaviour

Personality pathology in people with dementia committing homicide was also infrequently considered. This is perhaps surprising given that impulsivity and mistrust in others can be viewed as red flags for interpersonal conflict [24, 49]. Only one relatively large case series systematically assessed for personality disorders in older homicide offenders, finding them present in 44%, with this comorbidity less likely in those aged 60 years or more [24]. Although some case series and reports noted a past history of aggression [27-29, 33], including prior violent criminal offending [5, 24] or domestic violence [27, 29] in homicide offenders, there was limited consideration of the intersection of life-long personality pathology with emergent CI in later life.

Aspects of antisocial personality disorder and psychopathy have been used to help explain motivations for homicide throughout the lifespan [24]. However, there are divergent views regarding the contribution and determination of premorbid personality pathology in older adults, including how these may be exacerbated by CI [27, 49]. The premise that personality pathology associated with psychopathy persists throughout the lifespan could explain delayed offending, with threshold for violence only reached alongside the emergence of cognitive decline [50]. Severe CI has been described to lead to an increase in agitation-paranoia, while frontally predominant disease tends to escalate disinhibition [49]. This cerebral dysfunction may present similarly to impulsive and mistrustful personality pathology associated with antisocial behaviour [24, 49]. Alternatively, the coarsening of longstanding antisocial personality pathology may explain violence by people with dementia [50]. Clinicians may find it more difficult to apply diagnostic criteria of antisocial personality disorder to older adults as there could be a “bias of lapsed time” with incorrect recollections, particularly in people with dementia [24]. There may also be a lack of longitudinal collateral history. This may explain the relative absence of consideration of personality in the reviewed studies. It is also possible that the prevalence of antisocial personality pathology declines with ageing, perhaps due to related premature mortality, leading to underreporting of this factor associated with homicide [51].

Victim Vulnerability

Proximity to the offender emerged as a key risk factor for an individual to become a homicide victim [3, 17, 26, 28, 29]. Victims were overwhelmingly a current female domestic partner [5, 22, 24, 25, 27, 29-31], although ex-wives who remained within their ex-husband’s locality were also victims [28, 32]. For those in residential aged care facilities, resident-to-resident aggression may be triggered by perceived invasion of personal space or communication problems [16]. The risk of an assault resulting in death is heightened by the victim’s frailty. While a younger carer or staff may be able to ward off physical assault, an older spouse or co-resident is more vulnerable [3, 14, 16, 17, 40]. It has been posited that as many individuals age, their social sphere decreases due to various factors including reduced mobility and ill health [3]. Those closest to the offender are more vulnerable to assault, with stranger homicides a rarity in the older adults [3]. This has been demonstrated in studies examining aggressive behaviour of people with dementia towards healthcare staff, family, and the public [14, 17, 40]. The combination of proximity to the victim and vulnerability of the victim to death following assault is important as some homicides may not be committed with lethal intent [16, 23]. Thus, the outcome of aggression resulting in death may be due to the frailty of the victim and their incidental proximity to the person with dementia (offender).

Delirium

People with dementia are at high risk of developing delirium, which may cause or exacerbate behavioural disturbance [18, 52]. In the majority of studies reviewed, the possibility of delirium at the time of the offence was not explored – including in a case where the patient was described as “confused… agitated… nonsensical” (pp.889 [27]). Delirium is commonly misdiagnosed and under-recognized for a variety of reasons [52, 53], including diagnostic overshadowing in people with dementia [52, 54]. It is important to identify as with appropriate treatment delirium may be reversible [52, 54]. In hospitalized patients >65 years old admitted under geriatricians, up to 80% may have dementia, with 62% developing comorbid delirium [55]. This highlights the importance of screening for delirium in people with dementia [55]. Given that a “hyperactive” delirium can present with psychomotor agitation and aggression, it may also be a reversible factor for severe aggression resulting in homicide [54].

Implications for Clinical Practice

This review highlighted a topic which, although uncommon, is significant considering the impact of homicide. Given the ageing population and increasing prevalence of dementia, the recognition and management of associated symptoms of dementia such as aggression will become increasingly relevant to healthcare providers [3, 6, 14]. In parallel, there may be an increase in numbers of people with dementia committing serious offences, including homicide, being presented to the Correctional and Justice System [2, 8].

Educational Interventions

While there is a body of literature regarding older adults and associations with various criminal offences (both violent and nonviolent) [3, 14, 56], knowledge of the specific risk factors most pertinent for homicide is an important target for clinician education and could aid prioritization of targeted interventions for prevention [2, 13]. Education of primary care is essential as the majority of older people with dementia receive their healthcare from general practitioners rather than specialist services. In relation to family violence, for example, a lack of training for screening regarding specific issues faced by older adult victims has been identified in healthcare professionals [57, 58]. Any clinicians caring for people with dementia with the risk factors highlighted by this review must consider the safety of potential high-risk victims such as co-residents in aged care facilities and spouses, especially where there has been intimate partner violence [58]. Counselling spouses and carers regarding the particular risks and circumstances where aggression may arise and strategies to avoid, defuse, or escape dangerous situations may save lives [57]. Clinicians can also provide carers with information about the causes and management of aggression and agitation in dementia and support services [59, 60]. It is important for education to directly address concerns about the disclosure of information against a patient’s consent and the limits of confidentiality where there are risks involved as clinicians may lack knowledge of these issues [61, 62]. In dealing with older homicide offenders with dementia, additional resources and education may be indicated for court liaison clinicians in order to identify presentations suitable for diversion pathways and treatment [38, 39].

Comprehensive Assessment of People with Dementia and Changed Behaviours

There is a need for systematic assessment of older people with dementia and changed behaviours in order to provide optimal management, specifically considering the identified associated factors to help reduce severe assaults [3, 14, 16, 17, 40]. Primary care provides a setting for opportunistic screening including for hazardous alcohol use [46] and domestic violence [24]. Further, clinicians should have a high index of suspicion for delirium when there is an acute change in mental state given the greater vulnerability to delirium in people with dementia [63]. These risk factors may be potentially reversible with treatment. It is also important to check for persecutory delusions regarding specific targets [23, 34]. Assessments should ensure they include separate review of patients and carers to encourage open communication, especially of risk issues [64]. The assistance of professional interpreters, when needed, is essential [23, 34, 65].

Facilities for Homicide Offenders with Dementia

Specialized facilities with trained staff and appropriate environments to manage older homicide offenders with dementia were identified as a gap in existing services [5, 16, 22, 24, 26, 27], with long-term secure facilities recommended [5, 26]. Specifically, increased staffing ratios and environmental designs which optimize visibility in the facility may help to reduce aggressive interactions [5, 16, 22, 24, 26, 27]. Tailored management, including both pharmacological and nonpharmacological approaches, is recommended for aggression management in dementia [18, 66]. Given the particular challenges in assessment and management of older offenders with dementia, there should also be consideration of specialized geriatric forensic psychiatry services [5, 16, 22, 24, 26, 27].

Limitations

Limitations of Included Studies

Due to the rarity of homicide by older people with dementia, only observational studies are feasible, although case-control or cohort studies are possible and would raise the level of evidence [35]. Low-level evidence predisposes to overestimating hypothetical effects or inferences [36]. Reported characteristics of homicide offenders with dementia derived from these studies with low-level evidence were therefore discussed in light of the broader literature to highlight implications for clinical practice.

Surprisingly, depression was rarely considered in the included articles, despite the wider literature identifying depressive illnesses as one of the most common diagnostic categories in older adult offenders, including homicides [3, 4, 14, 50]. This may be explored in murder-suicide cases [67], which are not detected when information is gathered from open court records [22, 32, 33]. Our methodology located only one case of murder-suicide [31].

Limitations of the Systematic Review

Limitations of this review include the exclusion of grey literature or unpublished studies. Reporting bias is likely given the intrinsic ethical and legal complications associated with homicide by people with dementia. It is important to highlight that in those studies which reviewed court documents to gather data there may be coding errors due to legal nomenclature differing from the language of clinical practice [22]. The judgement transcript may give priority to answering the question of fitness to plead rather than making a specific diagnosis [22]. As our methodology excluded those <55, our review data cannot be extrapolated to younger offenders with dementia. Additionally, generalizability may be limited due to only including literature published in English. As a further challenge, a number of the studies evaluating homicide in older people were not primarily designed to assess dementia and so included limited subgroup analysis.

Rare outcomes such as homicide by people with dementia cannot be reliably predicted. However, notwithstanding the limitations of the literature to date, knowledge of the characteristics of people with dementia who commit homicide could help guide clinical practice. Psychosis may be a contributor to the choice of victim or reasoning behind a homicide; as such, it is essential to treat these symptoms. Personality pathology may also increase the risk of focused aggression. Dysexecutive syndrome, alcohol use, and delirium may increase the risk of disinhibition and consequently violent behavioural outbursts, which may result in homicide.

This review highlighted the complex interaction of medical, psychiatric, and environmental factors, including aspects of victim vulnerability, which may underlie homicide by people with dementia. Given the increased frailty of older homicide victims, measures to reduce overall aggression in people with dementia may also reduce the risk of homicide. A comprehensive assessment and formulation of aggression in a person with dementia, particularly considering the parameters identified in this review, may be useful in order to clearly identify and mitigate potential contributing factors. In terms of prevention, primary care is well positioned to screen for and manage potentially contributory comorbidity in people with dementia and to engage with spouses and carers, who may be at particular risk of severe aggression. Clinician education is needed to highlight the characteristics of people with dementia who are at greatest risk of offending. Future retrospective cohort or case-control studies with adequate power may assist in further understanding the strength and relationship between these clinical factors. Such data could inform recommendations for the management of this population in both the Health and Correctional Systems, including the development of specialized geriatric forensic psychiatry services and settings of care.

The paper is exempt from Ethical Committee approval due to reviewing previously published literature.

The authors have no conflicts of interest to declare.

The authors have no relevant funding details.

Dr. Tali Elsayed Sundakov-Krumins, Dr. Sean Lubbe, and A/Professor Anne Pamela Frances Wand contributed to the design of this systematic review, to the analysis of the results, and to the writing of the manuscript.

All data generated or analysed during this study are included in this article. Further enquiries can be directed to the corresponding author.

1.
United Nations Office on Drugs and Crime
.
Global Study on homicide 2019
. Available from: https://www.unodc.org/documents/data-and-analysis/gsh/Booklet2.pdf Accessed June 6, 2020.
2.
Tomar
R
,
Treasaden
IH
,
Shah
AK
.
Is there a case for a specialist forensic psychiatry service for the elderly?
Int J Geriatr Psychiatry
.
2005
;
20
:
51
6
. .
3.
Overshott
R
,
Rodway
C
,
Roscoe
A
,
Flynn
S
,
Hunt
IM
,
Swinson
N
,
Homicide perpetrated by older people
.
Int J Geriatr Psychiatry
.
2012
;
27
(
11
):
1099
105
.
4.
Regan
JJ
,
Alderson
A
,
Regan
WM
.
Psychiatric disorders in aging prisoners
.
Clin Gerontologist
.
2003
;
26
(
1-2
):
117
24
. .
5.
Reutens
S
,
Nielssen
O
,
Large
M
.
Homicides by older offenders in New South Wales between 1993 and 2010
.
Australas Psychiatry
.
2015
;
23
(
5
):
493
5
. .
6.
Yorston
G
.
Aged and dangerous. Old-age forensic psychiatry
.
Br J Psychiatry
.
1999
;
174
:
193
5
. .
7.
Baidawi
S
,
Turner
S
,
Trotter
C
,
Browning
C
,
Collier
P
,
Sheehan
R
.
Older prisoners-a challenge for Australian corrections
.
Trends Issues Crime Crim Justice
.
2011
;
423
:
1
11
.
8.
Yorston
GA
,
Taylor
PJ
.
Commentary: older offenders: no place to go?
J Am Acad Psychiatry Law
.
2006
;
34
(
3
):
333
7
.
9.
Lewis
CF
,
Fields
C
,
Rainey
E
.
A study of geriatric forensic evaluees: who are the violent elderly?
J Am Acad Psychiatry Law
.
2006
;
34
(
3
):
324
32
.
10.
Fazel
S
,
Hope
T
,
O'Donnell
I
,
Piper
M
,
Jacoby
R
.
Health of elderly male prisoners: worse than the general population, worse than younger prisoners
.
Age Ageing
.
2001
;
30
(
5
):
403
7
. .
11.
Turner
S
,
Trotter
C
.
Growing old in prison? A review of national and international research on Ageing Offenders
.
Melbourne, VIC
:
2010
. Available from: https://www.corrections.vic.gov.au/sites/default/files/embridge_cache/emshare/original/public/2019/04/a7/346b3be09/corrections_research_paper3_web2010.pdf Accessed February 19, 2020.
12.
World Health Organisation
.
Global action plan on the public health response to dementia 2017–2025
.
World Health Organisation
;
2019
. Available from: https://apps.who.int/iris/bitstream/handle/10665/259615/9789241513487-eng.pdf;jsessionid=4DA480FA93471AC53988E52B35F416D8?sequence=1 Accessed February 20, 2020.
13.
Yorston
G
.
Older people
.
Crim Behav Ment Health
.
2004
;
14
(
Suppl 1
):
S56
7
. .
14.
Cipriani
G
,
Lucetti
C
,
Danti
S
,
Carlesi
C
,
Nuti
A
.
Violent and criminal manifestations in dementia patients
.
Geriatr Gerontol Int
.
2016
;
16
(
5
):
541
9
. .
15.
Mann
JJ
.
Neurobiology of suicidal behaviour
.
Nat Rev Neurosci
.
2003
;
4
(
10
):
819
28
. .
16.
Murphy
B
,
Bugeja
L
,
Pilgrim
J
,
Ibrahim
JE
.
Deaths from resident-to-resident aggression in Australian nursing homes
.
J Am Geriatr Soc
.
2017
;
65
(
12
):
2603
9
. .
17.
Roberto
KA
,
McCann
BR
,
Brossoie
N
.
Intimate partner violence in late life: an analysis of national news reports
.
J Elder Abuse Negl
.
2013
;
25
(
3
):
230
41
. .
18.
New South Wales Health, Mental Health Branch
.
Assessment and management of people with behavioural and psychological symptoms of dementia [BPSD]
.
New South Wales Health
;
2013
. Available from: https://www.health.nsw.gov.au/mentalhealth/resources/Pages/assessment-mgmt-people-bpsd.aspx Accessed February 17, 2020.
19.
Leach
J
,
Neto
A
.
Offender population trends: aged offenders in NSW 2011
. Available from: https://www.correctiveservices.justice.nsw.gov.au/Documents/2012-30.pdf Accessed March 27, 2020.
20.
Kmet
LM
,
Lee
RC
,
Cook
L
.
Standard quality assessment criteria for evaluating primary research papers from a variety of fields
Alberta Heritage Foundation for Medical Research
;
2004
. Available from: http://www.ihe.ca/advanced-search/standard-quality-assessment-criteria-for-evaluating-primary-research-papers-from-a-variety-of-fields Accessed May 6, 2020.
21.
Lee
SY
,
Fisher
J
,
Wand
APF
,
Milisen
K
,
Detroyer
E
,
Sockalingam
S
,
Developing delirium best practice: a systematic review of education interventions for healthcare professionals working in inpatient settings
.
Eur Geriatr Med
.
2020
;
11
(
1
):
1
32
.
22.
Baird
A
,
Kennett
J
,
Schier
E
.
Homicide and dementia: an investigation of legal, ethical, and clinical factors of Australian legal cases
.
Int J Law Psychiatry
.
2020
;
71
:
101578
13
. .
23.
Nielssen
O
,
Large
MM
.
Homicide in psychiatric hospitals in Australia and New Zealand
.
Psychiatr Serv
.
2012
;
63
(
5
):
500
3
. .
24.
Putkonen
H
,
Weizmann-Henelius
G
,
Repo-Tiihonen
E
,
Lindberg
N
,
Saarela
T
,
Eronen
M
,
Homicide, psychopathy, and aging--a nationwide register-based case-comparison study of homicide offenders aged 60 years or older
.
J Forensic Sci
.
2010
;
55
(
6
):
1552
6
.
25.
Richard-Devantoy
S
,
Gallarda
T
,
Annweiler
C
,
Dorey
JM
,
Mesu
C
,
Garré
JB
,
Homicide and dementia in older adults: the key role of dysexecutive function
.
J Clin Psychiatry
.
2010
;
71
(
10
):
1402
3
.
26.
Hindley
N
,
Gordon
H
.
The elderly, dementia, aggression and risk assessment
.
Int J Geriatr Psychiatry
.
2000
;
15
(
3
):
254
9
. .
27.
Dinniss
S
.
Violent crime in an elderly demented patient
.
Int J Geriatr Psychiatry
.
1999
;
14
(
10
):
889
91
. .
28.
Rayel
MG
,
Land
WB
,
Gutheil
TG
.
Dementia as a risk factor for homicide
.
J Forensic Sci
.
1999
;
44
(
3
):
565
7
.
29.
Ticehurst
SB
,
Gale
IG
,
Rosenberg
SJ
.
Homicide and attempted homicide by patients suffering from dementia: two case reports
.
Aust N Z J Psychiatry
.
1994
;
28
(
1
):
136
40
. .
30.
Ciccone
JR
.
Murder, insanity, and medical expert witnesses
.
Arch Neurol
.
1992
;
49
(
6
):
608
11
. .
31.
Lecso
PA
.
Murder-suicide in Alzheimer’s disease
.
J Am Geriatr Soc
.
1989
;
37
(
2
):
167
8
. .
32.
Wilcox
DE
.
The relationship of mental illness to homicide
.
Am J Forensic Psychiatry
.
1985
;
6
(
1
):
3
15
.
33.
Schier
E
,
Baird
A
,
Kennett
J
.
Dataset of published Australian of homicide in which the accused had a diagnosis of dementia
.
2020
. Accessed August 30, 2020.
34.
Ticehurst
SB
,
Ryan
MG
,
Hughes
F
.
Homicidal behaviour in elderly patients admitted to a psychiatric hospital
.
Dement Geriatr Cogn Disord
.
1992
;
3
(
2
):
86
90
. .
35.
Burns
PB
,
Rohrich
RJ
,
Chung
KC
.
The levels of evidence and their role in evidence-based medicine
.
Plast Reconstr Surg
.
2011
;
128
(
1
):
305
10
. .
36.
Nissen
T
,
Wynn
R
.
The clinical case report: a review of its merits and limitations
.
BMC Res Notes
.
2014
;
7
:
264
. https://pubmed.ncbi.nlm.nih.gov/24758689
37.
American Psychiatric Association
.
Diagnostic and statistical manual of mental disorders
. 5th ed.
Arlington, VA
:
American Psychiatric Association
;
2013
.
38.
Guarino
A
,
Favieri
F
,
Boncompagni
I
,
Agostini
F
,
Cantone
M
,
Casagrande
M
.
Executive functions in Alzheimer disease: a systematic review
.
Front Aging Neurosci
.
2019
;
10
:
437
. .
39.
Manoochehri
M
,
Huey
ED
.
Diagnosis and management of behavioral issues in frontotemporal dementia
.
Curr Neurol Neurosci Rep
.
2012
;
12
(
5
):
528
36
. .
40.
Liljegren
M
,
Landqvist Waldö
M
,
Englund
E
.
Physical aggression among patients with dementia, neuropathologically confirmed post-mortem
.
Int J Geriatr Psychiatry
.
2018
;
33
(
2
):
e242
8
. .
41.
Kim
M
,
Leigh
JH
,
Han
MH
.
The value of frontal assessment battery in stroke patients
.
Ann Phys Rehabil Med
.
2018
;
61
:
180
.
42.
World Health Organization
.
International classification of diseases for mortality and morbidity statistics [11th Revision] 2018
.
World Health Organization
;
2020
. Available from: https://icd.who.int/browse11/l-m/en Accessed April 4, 2020.
43.
Berger
JR
,
Dean
D
.
Neurosyphilis
.
Handb Clin Neurol
.
2014
;
121
:
1461
72
. .
44.
Cipriani
G
,
Vedovello
M
,
Nuti
A
,
di Fiorino
A
.
Dangerous passion: othello syndrome and dementia
.
Psychiatry Clin Neurosci
.
2012
;
66
(
6
):
467
73
. .
45.
Graham
K
,
Livingston
M
.
The relationship between alcohol and violence: population, contextual and individual research approaches
.
Drug Alcohol Rev
.
2011
;
30
(
5
):
453
7
. .
46.
Rao
R
,
Roche
A
.
Substance misuse in older people
.
BMJ
.
2017
;
358
:
j3885
. .
47.
Kelly
S
,
Olanrewaju
O
,
Cowan
A
,
Brayne
C
,
Lafortune
L
.
Alcohol and older people: a systematic review of barriers, facilitators and context of drinking in older people and implications for intervention design
.
PLoS One
.
2018
;
13
(
1
):
e0191189
. https://pubmed.ncbi.nlm.nih.gov/29370214
48.
Abernathy
K
,
Chandler
LJ
,
Woodward
JJ
.
Alcohol and the prefrontal cortex
.
Int Rev Neurobiol
.
2010
;
91
:
289
320
. .
49.
Mendez
MF
,
Shapira
JS
,
Saul
RE
.
The spectrum of sociopathy in dementia
.
J Neuropsychiatry Clin Neurosci
.
2011
;
23
(
2
):
132
40
. .
50.
Coid
J
,
Fazel
S
,
Kahtan
N
.
Elderly patients admitted to secure forensic psychiatry services
.
J Forensic Psychiatry
.
2002
;
13
(
2
):
416
27
. .
51.
Repo-Tiihonen
E
,
Virkkunen
M
,
Tiihonen
J
.
Mortality of antisocial male criminals
.
J Forensic Psychiatry
.
2001
;
12
(
3
):
677
83
. .
52.
Fick
DM
,
Agostini
JV
,
Inouye
SK
.
Delirium superimposed on dementia: a systematic review
.
J Am Geriatr Soc
.
2002
;
50
(
10
):
1723
32
. .
53.
Welch
C
,
McCluskey
L
,
Wilson
D
,
Chapman
GE
,
Jackson
TA
,
Treml
J
,
Delirium is prevalent in older hospital inpatients and associated with adverse outcomes: results of a prospective multi-centre study on world delirium awareness day
.
BMC Med
.
2019
;
17
(
1
):
229
.
54.
Gonin
P
,
Beysard
N
,
Yersin
B
,
Carron
PN
.
Excited delirium: a systematic review
.
Acad Emerg Med
.
2018
;
25
(
5
):
552
65
. .
55.
De
J
,
Wand
APF
,
Smerdely
PI
,
Hunt
GE
.
Validating the 4A’s test in screening for delirium in a culturally diverse geriatric inpatient population
.
Int J Geriatr Psychiatry
.
2017
;
32
(
12
):
1322
9
. .
56.
Heinik
J
,
Kimhi
R
,
Hes
JP
.
Dementia and crime: a forensic psychiatry unit study in Israel
.
Int J Geriat Psychiatry
.
1994
;
9
(
6
):
491
4
. .
57.
SafeLives
.
Safe later lives: older people and domestic abuse
.
SafeLives
;
2016
. Available from: https://safelives.org.uk/sites/default/files/resources/Safe%20Later%20Lives%20-%20Older%20people%20and%20domestic%20abuse.pdf Accessed February 29, 2021.
58.
Wijeratne
C
,
Reutens
S
.
When an elder is the abuser
.
Med J Aust
.
2016
;
205
(
6
):
246
7
. .
59.
National Institute on Aging
.
Coping with agitation and aggression in Alzheimer’s disease
.
National Institute on Aging
;
2017
. Available from: https://www.nia.nih.gov/health/coping-agitation-and-aggression-alzheimers-disease.
60.
National Health Service
.
Coping with dementia behaviour changes
.
National Health Service
;
2021
. Available from: https://www.nhs.uk/conditions/dementia/behaviour/.
61.
Ryan
CJ
,
Callaghan
S
,
Large
MM
.
Communication, confidentiality and consent in mental health care
.
Med J Aust
.
2014
;
200
(
1
):
9
. .
62.
Wand
APF
,
Draper
B
,
Brodaty
H
,
Hunt
GE
,
Peisah
C
.
Evaluation of an educational intervention for clinicians on self-harm in older adults
.
Arch Suicide Res
.
2021 Jan–Mar
;
25
(
1
):
156
76
. .
63.
Fong
TG
,
Davis
D
,
Growdon
ME
,
Albuquerque
A
,
Inouye
SK
.
The interface between delirium and dementia in elderly adults
.
Lancet Neurol
.
2015
;
14
:
823
32
. .
64.
Wand Apf
DB
,
Brodaty
H
,
Peisah
C
.
Self harm in late life. How can the GP help?
Med Today
.
2019
;
20
(
7
):
33
6
.
65.
Wand
APF
,
Pourmand
D
,
Draper
B
.
Working with interpreters in the psychiatric assessment of older adults from culturally and linguistically diverse backgrounds
.
Int Psychogeriatr
.
2020
;
32
(
1
):
11
6
. .
66.
Gilmore
MC
,
Stebbins
L
,
Argüelles-Borge
S
,
Trinidad
B
,
Golden
CJ
.
Development and treatment of aggression in individuals with dementia
.
Aggression Violent Behav
.
2020
;
54
:
101415
. .
67.
Eliason
S
.
Murder-suicide: a review of the recent literature
.
J Am Acad Psychiatry Law
.
2009
;
37
:
371
6
.
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