Criminal Behavior in the Four Years Preceding Diagnosis of Neurocognitive Disorder: A Nationwide Register Study in Finland

Abstract

Objective: To explore the criminality of patients with subsequent diagnosis of Alzheimer's disease (AD), frontotemporal dementia (FTD), or Lewy body dementias (LBD) in the four years preceding diagnosis.

Design: Nationwide register study.

Setting: Data on Finnish patients were collected from the discharge register and data on criminal offending from the police register. Research findings were compared with the same-aged general population.

Participants: A total of 92,191 patients who had received a diagnosis of AD (N = 80,540), FTD (N = 1,060), and LBD (N = 10,591) between 1998 and 2015.

Measurements: Incidences and types of crimes, the standardized criminality ratio (number of actual crimes per number of expected crimes), and the numbers of observed cases and person-years at risk counted in five-year age groups and separately for both genders and yearly.

Results: At least one crime was committed by 1.6% of AD women and 12.8% of AD men, with corresponding figures of 5.3% and 23.5% in FTD, and 3.0% and 11.8% in LBD. The first crime was committed on average 2.7 (standard deviation 1.1) years before the diagnosis. The standardized criminality ratio was 1.85 (95% confidence interval [CI] 1.43-2.37) in FTD women and 1.75 (95% CI 1.54-1.98) in FTD men, and in AD 1.11 (95% CI 1.04-1.17) and 1.23 (95% CI 1.20-1.27), respectively. Traffic offences and crimes against property constituted 94% of all offences.

Conclusion: Criminal acts may occur several years prior to the diagnosis of dementia. If novel criminality occurs later in life, it may be associated with neurocognitive disorder.

Keywords: Neurocognitive disorder; behavioral symptoms; crime; criminal; dementia; offence.