Grumpy old men: agitation, aggression, and impulsivity in older adults and risk of incident dementia

Background Impulse dyscontrol, i.e., excessive motor activity and/or physical and verbal aggression is common in dementia. However, impulse dyscontrol can also emerge in advance of dementia, but is often normalized due to age, or framed as a psychiatric condition. Thus, the association between these symptoms and incident dementia is unclear. Mild behavioral impairment (MBI) leverages risk associated with later‐life emergent and persistent neuropsychiatric symptoms (NPS) to identify a high‐risk group for incident dementia. Impulse dyscontrol is one of five MBI domains. Here, in dementia‐free participants, we assessed risk of progression to dementia in MBI‐impulse dyscontrol and conventionally‐measured impulse dyscontrol symptoms (Conv‐ID). Method Dementia‐free National Alzheimer Coordinating Centre participants were included. Neuropsychiatric Inventory Questionnaire irritability, agitation, and aberrant motor behavior items were used to identify impulse dyscontrol. MBI‐impulse dyscontrol was operationalized by symptom presence at more than two‐thirds of pre‐dementia study visits (symptom persistence criterion) in those with no history of psychiatric disorders (symptom emergence criterion). Conv‐ID required symptoms only at baseline without consideration of past psychiatric history. Kaplan‐Meier survival curves and Cox proportional hazards models, adjusted for age, sex, education, race, and APOE‐e4 status, were generated to compare survival probability and dementia incidence rates of MBI‐impulse dyscontrol and Conv‐ID to No‐NPS. Results The sample comprised 1,884 MBI‐impulse dyscontrol (age = 74.5±9.7; 40.9% female), 3,676 Conv‐ID (age = 71.0±9.4; 47.0% female), and 6,362 No‐NPS participants (age = 71.0±10.3; 64.7% female) (Table 1). MBI‐impulse dyscontrol had lower dementia‐free survival (p