Previous research has demonstrated an association between the emotional and behavioral symptoms of dementia, known as neuropsychiatric symptoms, and cognitive and functional decline among patients with Alzheimer disease (AD). The present study aimed to identify associations between neuropsychiatric symptoms as measured by the Neuropsychiatric Inventory-Questionnaire (NPI-Q) and cognitive and functional performance. Participants were 256 AD patients enrolled in the Alzheimer's Disease and Memory Disorders Center at Baylor College of Medicine. An exploratory factor analysis of the NPI-Q indicated a 2-factor structure consisting of Negative/Oppositional and Anxiety/Restlessness factors. Regression analyses revealed significant associations between greater total severity of neuropsychiatric symptoms and poorer performance on basic and Instrumental Activities of Daily Living. Greater severity of Anxiety/Restlessness symptoms was associated with poor performance on measures of visuospatial functioning and basic and instrumental activities of daily living. The Negative/Oppositional factor was not related to cognition or functioning. In summary, neuropsychiatric symptoms (particularly Anxiety/Restlessness symptoms) were related to cognition and everyday functioning. Proper assessment and treatment of these symptoms is essential for improving cognition and functioning in AD patients.

These results indicate the importance of properly identifying and treating symptoms of posttraumatic stress in veterans with a history of mTBI, as posttraumatic stress symptoms appear to be strongly related to SWL in those with a history of mild TBI. Optimizing sleep quality and social support may also be important in improving SWL.

Findings suggest that testosterone is not associated with most neuropsychological test performances in patients with AD.

These results partially support previous findings and indicate that an association between impulsiveness and problematic behaviors exists in OEF/OIF/OND veterans, regardless of TBI history.