Effects of the Great East Japan Earthquake and the Fukushima Daiichi Nuclear Power Plant accident on behavioural and psychological symptoms of dementia among patients

Background: The Great East Japan Earthquake triggered accidents at the Fukushima Daiichi Nuclear Power Plant, becoming the first complex disaster that included both a natural and a nuclear power disaster. This study examines how complex disasters affect patients with dementia. Methods: Participants included the 331 people diagnosed with dementia out of the 2482 new patients (between January 2008 and December 2015) at a psychiatric hospital located in the indoor sheltering zones nearby mandatory evacuation zones. Medical records were retrospectively examined to identify the number of new patients with dementia, the severity, their chief complaints, and the behavioural and psychological symptoms of dementia (BPSD) types. BPSD were classified into the hyperactive BPSD group and the hypoactive BPSD group. The hyperactive BPSD group was further subdivided into the hyperactivity-impulsivity-irritability-disinhibition-aggression-agitation group, which exhibited agitation, disinhibition, and irritability, and the psychosis group, which exhibited delusions and hallucinations. The hypoactive BPSD group included depression, inactivity, apathy, and anxiety. Results were divided into the period before the complex disaster (2008–2010) and after (2012–2015) and were compared. In addition, the post-complex-disaster period was subdivided into the early phase (2012–2013) and the late phase (2014–2015). Results: The proportion of new patients with dementia increased significantly after the disaster. Although there was no change in patients' age and the disease's severity, the proportion of patients whose chief complaint was BPSD increased significantly after the disaster. Furthermore, there was a significant increase in the hyperactivity-impulsivity-irritability-disinhibition-aggression-agitation group in the early post-complex-disaster phase and a significant increase in the psychosis group in the late post-complex-disaster phase. Conclusion: This complex disaster caused increased consultations from patients with dementia and increased BPSD. Additionally, it increased participants' symptoms of agitation and irritability in the early post-complex-disaster phase and the proportion of hallucinations and delusions in the late post-complex-disaster phase.