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.