Alzheimer's disease accounts for more than 60 percent of dementia cases, while vascular dementia (VaD) is the second most common cause of dementia, accounting for approximately 20 % of dementia cases.1 VaD results from neuronal oxygen and nutrient deprivation secondary to cerebrovascular injury and poor cerebral perfusion.1,2 This deprivation causes progressive neuronal death, which can result in vascular cognitive impairment (VCI) .3 VCI is not due to a single pathology, as it can be secondary to multiple vascular abnormalities such as infarction, hemorrhage, small arterial disease, cardio-embolism, and cardiovascular diseases.4 The initial conceptual framework for the description of VCI has been broadened to incorporate cerebrovascular disease and/or vascular brain injury with various cognitive impairments,5 including a plethora of neurocognitive disorders affiliated with cerebrovascular incidents that can range from a minor decline in cognition to VaD.6 VCI has several clinical presentations including hypoperfusion dementia, post-stroke dementia, and multiple microinfarcts to executive functions that are linked to neuropsychiatric and behavioral symptoms.7

Neuropsychiatric symptoms (NPS) or behavioral disturbances are very common in AD and VaD patients.8 NPS is thought to result from cortical brain abnormalities, specifically of the frontal lobe.9 The most prevalent symptoms seen with VCI were irritability/agitation, eating disorders, apathy, depression, and anxiety.10 Several lines of evidence indicate that NPS is prevalent in dementia patients8,9,11 which has been shown to affect patients' quality of life and their clinical outcomes, resulting in multimorbidity and disability.12,13 In a broader spectrum of NPS and dementia, neurological symptoms including psychomotor agitation, irritability, depression, and anxiety; psychiatric symptoms such as disinhibition, apathy, hallucinations, motor behaviors, and delusions may differ14 based on the pathophysiological mechanisms of dementia, and specific neuroanatomic circuits that are affected.19 For example, there may be a higher rate of “negative-like” symptoms in AD patients such as psychomotor retardation and loss of interest whereas increased “affective-like” symptoms may be seen in VaD patients.15 Furthermore, psychotic symptoms are reported to be more associated with VaD while AD patients experience neurological symptoms.16

Risk factors for dementia subtypes, including VaD and AD, vary.29 Some risk factors, including hypertension, hyperlipidemia, and atherosclerotic disease, are prevalent in both AD and VaD patients,19,24 especially in patients greater than or equal to 65 years old.17 Additionally, there is a reduction in cerebrovascular function seen in patients with dementia, classifying cerebrovascular dysfunction such as cerebrovascular accident, and aneurysm as a risk factor.18 Another feature of VaD is a metabolic syndrome, its main components include dyslipidemia, insulin resistance, and hypertension.19 Atherosclerosis has been noted in patients clinically diagnosed with VaD or AD.20 An association between high blood pressure and AD risk has been reported.21 Diabetes, a high level of cholesterol, tobacco smoking, and other risk factors are also linked with AD risk.22 Furthermore, hypertension,23 and atrial fibrillation22have been observed among AD patients.24 The risk factors that are more associated with NPS within these two dementia subtypes are not well understood. Risk factors vary according to dementia subtype and severity.25 Moreover, NPS also varies between AD and VaD indicating that risk factors of AD and VaD with NPS may be different in comparison to dementia patients.26 Therefore, the hypothesis tested in this study is that risk factors associated with VaD and AD with NPS will be different among the population of dementia patients. Identifying different risk factors between VaD and AD in NPS populations was the first objective. It is possible that VaD and AD patients with NPS may have different risk factors. For the second objective, we will determine risk factors that contribute to differences in VaD and AD with NPS. Understanding similarities and differences between AD and VaD risk factors with NPS might create new opportunities for the care of both AD and VaD with behavioral disturbances.