Homicide and Dementia: A Systematic Review

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 characteristics of older homicide offenders: a systematic review

This systematic review was conducted to develop a broader understanding of the characteristics of older people who commit homicide. PubMed, Embase and PsycINFO were searched on 28 November 2018 for studies on homicides committed by people aged 55 years and over. Only articles published in English were included. Studies focusing on euthanasia and palliation were excluded. Fifteen articles met the inclusion criteria, with studies from the United States (n = 6), United Kingdom (n = 2), Australia, Canada, Finland, Italy, New Zealand, Switzerland and Turkey. The age range for 'older offenders' varied across the studies. Some studies examined the phenomena of sexual homicide and homicide-suicide. Offenders were more likely to be male, and the domestic setting for the offence was common. Social maladjustment, a care-giver role, personal physical and mental health problems and/or substance misuse issues were relevant to the offenders. Firearms-related homicides were common. Homicide committed by older people is rare but there may be a constellation of risk factors specific to this age group that needs further understanding. Our findings suggest that there is an increasing need for care of older offenders and a need for specialist forensic services for elderly offenders.