Traumatic Brain Injuries, Alzheimer’s Disease and Dementia

A 1990 case report by Roberts et al. ^{Reference Roberts, Whitwell, Acland and Bruton8} describing a 76-year-old woman with dementia connects the topics of IPV and AD. A woman was found unconscious with head contusions; her relatives disclosed that her husband had been abusive for years. A post-mortem brain examination revealed morphological and immunological characteristics typically reported in patients with CTE. These factors suggested that the woman’s IPV-associated brain trauma contributed significantly to the development and progression of her dementia. This case report was published a staggering 60 years after studies began to investigate the long-term effects of brain trauma in retired boxers, highlighting the significant time lag and lack of consideration for CTE outside the sports context, especially for women who bear an overwhelmingly higher risk of IPV. However, TBI research remains heavily focussed on contact sports, leaving the victims of IPV seemingly invisible in this important conversation.

The consequences of TBIs are significant, with some authors even suggesting, although controversially, that even a single TBI may double one’s likelihood of developing dementia. ^{Reference Brett, Gardner, Godbout, Dams-O’Connor and Keene1} Repeated TBIs, especially episodes associated with inflicted structural pathologies, have clearly been identified as risk factors for dementia; a study of 2,223 individuals found that people with dementia were twice as likely to report having had multiple TBIs throughout their lifetime, relative to a first-degree control group. ^{Reference Brett, Gardner, Godbout, Dams-O’Connor and Keene1} This evidence suggests that experiencing repetitive or moderate-severe TBIs is a risk factor for the development of dementia in later life. TBIs have also been associated with the formation of AD-specific pathological proteins, including hyperphosphorylated tau tangles and β-amyloid (Aβ) plaques. ^{Reference Brett, Gardner, Godbout, Dams-O’Connor and Keene1} TBIs are highly prevalent amongst victims of IPV, arguably leaving hundreds of millions of women worldwide at increased risk for developing dementia.

Depression, PTSD and Related Mental Illnesses

The risks posed by IPV exceed the physical consequences that many victims experience. Psychological abuse, whether alone or in combination with physical or sexual assault, also inflicts serious effects on the brain. IPV can result in long-term psychological trauma. In an assessment of previously battered women, brain injuries were found to be associated with several psychological disorders including depression, post-traumatic stress disorder and anxiety. ^{Reference Mehr, Bennett and Price3}

Many psychological disorders, including depression, share neurobiological pathways with AD. ^{Reference Black, Basile and Breiding4} Dysregulation of the hypothalamic-pituitary-adrenal axis leads to hippocampal atrophy, often resulting in memory impairment and cognitive decline in both AD and depression. ^{Reference Byers and Yaffe9} Patients with AD and depression also exhibit increased deposition of Aβ plaques and neurofibrillary tangles, compared to controls. ^{Reference Byers and Yaffe9} Additionally, depression and acute stress can lead to the overproduction of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), which are characteristic of AD and related dementias. ^{Reference Byers and Yaffe9}

Women experiencing IPV may not disclose their psychological symptoms out of fear, shame or guilt, ultimately reducing the true salience of the effects of IPV. Furthermore, due to the underrepresentation of IPV in AD research, there are minimal resources for victims. Thus, there is a vital need for more research on the relationship between IPV, depression and AD; the victims of IPV need to be fully aware of possible long-term health consequences.

Addiction

The interconnected nature of substance addiction in IPV victims and its association with AD likewise warrants further study. Perpetrators may use illicit drugs, medications or alcohol as a means of control, preventing the victim from defending themselves physically and financially. Victims may become reliant on their intimate partners for access to these substances. Additionally, victims may self-medicate to cope with the psychological stress of IPV. Addiction is a comorbidity of IPV, with studies revealing that nearly half of the women who visit a shelter after IPV exposure meet the criteria for alcohol use disorder. ^{Reference Mehr, Bennett and Price3} Additionally, studies have noted that opiate use is four times higher among victims of IPV who seek medical care than in the general population. ^{Reference Mehr, Bennett and Price3}

Substance abuse increases the risk of AD by impacting memory and cognitive function. ^{Reference Hulse, Lautenschlager, Tait and Almeida10} For instance, excessive ethanol consumption is associated with the release of pro-inflammatory cytokines, further contributing to neuroinflammation and neurodegeneration. Moreover, opiate abuse is linked to increased brain levels of hyperphosphorylated tau. ^{Reference Majtenyi, Lutz, Hurd and Keller5}

Unfortunately, addiction frequently persists long term, predisposing victims to ongoing risk. Addiction may lead to the loss of employment, social isolation and housing instability; accordingly, women who suffer from addiction may find themselves in dangerous situations, in contact with other drug users and potentially exposed to even more IPV. Moreover, the associated social isolation is likewise a risk for AD. ^{Reference Guarnera, Yuen and Macpherson11} Thus, the relationship between IPV, addiction and AD is intricately interconnected and complex.

Concluding Statements

The issue of IPV and its connection to AD is multifaceted with evidence suggesting a potential link between repetitive or moderate-severe TBIs, psychological disorders, addiction and AD in women who have experienced IPV. This commentary, while not exhaustive, highlights a number of crucial observations as well as the need for more research to address the long-term ramifications of this important societal problem. Given the fact that women have a higher risk of developing dementia than men, recognising and addressing the risk factors for AD in women especially in the context of geriatrics and women’s brain health is a research priority – a priority that demands tangible results. ^{Reference Fratiglioni, Viitanen, von Strauss, Tontodonati, Herlitz and Winblad12} Primary research to address these important issues is needed. Moreover, possible gender bias in this research must be addressed since TBI research has traditionally focussed on male-centric activities such as contact sports.

Is it time to do something about it? This commentary is a call for research to address these questions. Violence against women is a global problem – an increased risk for AD may be an under-acknowledged consequence of this violence.