Year of Publication



Public Health

Date Available


Degree Name

Master of Public Health (M.P.H.)

Committee Chair

Wayne Sanderson, PhD, MS

Committee Member

Michael Singleton, PhD

Committee Member

Erin Abner, PhD



Dementia is a major public health issue both in the United States and worldwide. Alzheimer’s disease (AD) is widely considered to be the most prevalent type of dementia. While the hallmark AD symptom is profound memory loss, patients also commonly experience changes in personality and behavior. These changes often include depression, anxiety, social withdrawal, mood swings, irritability and aggression, changes in sleeping habits, and delusions.


Several studies have established a mechanistic link between traumatic brain injury (TBI) and the development of AD. However, it is unknown whether TBI contributes to the personality/behavior changes observed in many AD patients. The current study examined a possible association between TBI and psychiatric conditions in patients who present with clinically diagnosed dementia due to AD.


Participants in the current study were sampled from the National Alzheimer’s Coordinating Center dataset. Only participants who had AD at the time of their most recent assessment were included in the study (N=10,511). Logistic regression was used to analyze the association between TBI and adverse psychiatric outcomes (defined as presence of psychosis or agitation/aggression) in patients with AD. Confounding variables, including age, gender, education, and dementia severity, were included in final regression models.


Agitation/Aggression: This study found an association with alcohol abuse (OR: 1.87), age group of 65-74 (OR: 1.41), and having active diabetes in both the mild (OR: 1.21) and moderate (OR: 1.25) states of AD. A remote history of seizure in moderate AD had one of the strongest associations with increased odds of agitation/aggression (OR: 2.24). In those with severe AD and agitation/aggression, a protective association was found in those age 85+ (OR: 0.66), and in those with a recent history of urinary incontinence (OR: 0.59). Psychosis: The lowest educational attainment group had the highest risk of developing psychosis, with mild AD & 0- 12 years of education (OR: 1.67), those with moderate AD & 0-12 years of education (OR: 1.76), in those with moderate AD & 13-16 years of education (OR: 1.53). At a mild stage of AD there was a suggestive association with urinary incontinence (OR: 1.20). In addition, being age 85+ at a severe stage of AD had a suggestive protective association (OR: 0.67).


No significant association was found between TBI and psychiatric symptoms in persons with AD. However, there was evidence of an association between age, diabetes, alcohol abuse, urinary incontinence and seizures with agitation/aggression. Age, education level, and a recent history of incontinence are associated with increased odds of developing psychosis.

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