High Occurrence of Psychiatric Disorders and Suicidal Behavior Across Dementia Subtypes

Suicides in degenerative neurocognitive disorders and traumatic brain injuries

BACKGROUND

Neuropsychiatric symptoms in major neurocognitive disorders have been strongly associated with suicidality.

METHODS

The objectives were to explore suicide rates in degenerative neurocognitive disorders (DNDs), alcohol-related neurocognitive disorders (ARNDs), and traumatic brain injuries (TBIs). Patients who received these diagnoses between 1998 and 2015 (N = 231,817) were identified from nationwide registers, and their mortality was followed up until December 31, 2018. We calculated incidences of suicides per 100,000 person-years, types of suicides, and suicide rates compared with the general population (standardized mortality ratio [SMR]).

RESULTS

During the follow-up, 0.3% (95% confidence interval [95% CI]: 0.2-0.5) of patients with DNDs, 1.1% (0.7-1.8) with ARNDs, and 1.0% (0.7-1.3) with TBIs committed suicide. Suicide mortality rate was higher in men (58.9, 51.3, to 67.4 per 100,000) than in women (9.8, 7.5, to 12.5 per 100,000). The highest suicide rate was in ARNDs (98.8, 65.1, to 143.8 per 100,000), followed by TBIs (82.0, 62.4, to 105.8 per 100,000), and DNDs (21.2, 18.3, to 24.5 per 100,000). The SMRs (95% CI) were 3.69 (2.53-5.38), 2.99 (2.31-3.86), and 1.31 (1.13-1.51), respectively, and no sex difference emerged. The most common cause of death was self-inflicted injury by hanging or drowning (12.4, 10.3, to 14.8 per 100,000).

CONCLUSIONS

Suicide rates were higher in all three patient groups than the general population. Suicide risk remained elevated for more than 10 years after diagnosis. The suicide methods were mostly violent.

Exploring the interplay between dementia, multiple health conditions and couplehood: A qualitative evidence review and meta-ethnography

Background: On average, people with dementia live with 4.6 additional health conditions. Additionally, two thirds of carers of people with dementia are spouses, and are also likely to live with multimorbidity, given that older age is strongly associated with an increase in health conditions. Consequently, living with dementia and multimorbidity is often a shared experienced as a couple. However, research has not explored how living with both dementia and multimorbidity may impact on couplehood. Method: We conducted a qualitive evidence review using a meta-ethnographic approach, to answer the following question: In what way (if any) does living with dementia and multimorbidity impact on couplehood? No papers were found on couplehood, dementia and multimorbidity, therefore the review consists of a meta-synthesis of couples' experiences of living with dementia in relation to couplehood, with an additional search for any data related to health within the qualitative findings. Findings: Two major reciprocal themes and five subthemes were identified from the 14 study findings. 1. Change and adjustment in the relationship, which included themes around a sense of 'togetherness', change in roles and identity and developing shared coping strategies and 2. Commitment, which was encapsulated by themes on unconditional love and commitment to wedding vows. Health-related findings were limited but included the impact on emotional wellbeing and how other health conditions, rather than dementia, were attributed to a loss in physical sexual intimacy. Conclusion: This review found that couplehood was threatened when dementia symptoms progressed and couples experienced feelings of loss of independence and identity. However, a strong foundation of commitment, love and loyalty to each other developed over the course of the relationship, was the 'glue' that helped couples face dementia together. However, further research is needed to explore couples' experiences of living with both multimorbidity and dementia in relation to couplehood in order to develop holistic, relationship-centred interventions.

Diagnoses and Treatment of Behavioral and Psychological Symptoms of Dementia Among Racially and Ethnically Diverse Persons Living with Dementia

Background

Behavioral and psychological symptoms of dementia (BPSD) and prescribed central nervous system (CNS) active drugs to treat them are prevalent among persons living with Alzheimer's disease and related dementias (PLWD) and lead to negative outcomes for PLWD and their caregivers. Yet, little is known about racial/ethnic disparities in diagnosis and use of drugs to treat BPSD.

Objective

Quantify racial/ethnic disparities in BPSD diagnoses and CNS-active drug use among community-dwelling PLWD.

Methods

We used a retrospective cohort of community-dwelling Medicare Fee-for-Service beneficiaries with dementia, continuously enrolled in Parts A, B and D, 2017-2019. Multivariate logistic models estimated rates of BPSD diagnosis and, conditional on diagnosis, CNS-active drug use.

Results

Among PLWD, 67.1% had diagnoses of an affective, psychosis or hyperactivity symptom. White (68.3%) and Hispanic (63.9%) PLWD were most likely, Blacks (56.6%) and Asians (52.7%) least likely, to have diagnoses. Among PLWD with BPSD diagnoses, 78.6% took a CNS-active drug. Use was highest among whites (79.3%) and Hispanics (76.2%) and lowest among Blacks (70.8%) and Asians (69.3%). Racial/ethnic differences in affective disorders were pronounced, 56.8% of white PLWD diagnosed; Asians had the lowest rates (37.8%). Similar differences were found in use of antidepressants.

Conclusions

BPSD diagnoses and CNS-active drug use were common in our study. Lower rates of BPSD diagnoses in non-white compared to white populations may indicate underdiagnosis in clinical settings of treatable conditions. Clinicians' review of prescriptions in this population to reduce poor outcomes is important as is informing care partners on the risks/benefits of using CNS-active drugs.

Psychiatric Disorders Before and After Dementia Diagnosis

Importance

Little is known about the specific timing and sequence of incident psychiatric comorbidities at different stages of dementia diagnosis.

Objectives

To examine the temporal risk patterns of psychiatric disorders, including depression, anxiety, stress-related disorders, substance use disorders, sleep disorders, somatoform/conversion disorders, and psychotic disorders, among patients with dementia before, at the time of, and after receipt of a diagnosis.

Design, Setting, and Participants

This population-based, nationwide cohort study analyzed data from 796 505 participants obtained from 6 registers between January 1, 2000, and December 31, 2017, including the Swedish registry for cognitive/dementia disorders. Patients with dementia were matched on year of birth (±3 years), sex, and region of residence with up to 4 controls. Data were analyzed between March 1, 2023, and August 31, 2023.

Exposures

Any cause of dementia and dementia subtypes.

Main Outcomes and Measures

Flexible parametric survival models to determine the time-dependent risk of initial diagnosis of psychiatric disorders, from 7 years prior to dementia diagnosis to 10 years after diagnosis. Subgroup analysis was conducted for psychiatric drug use among persons receiving a diagnosis of dementia from January 1, 2011, to December 31, 2012.

Results

Of 796 505 patients included in the study (mean [SD] age at diagnosis, 80.2 [8.3] years; 448 869 (56.4%) female), 209 245 had dementia, whereas 587 260 did not, across 7 824 616 person-years. The relative risk of psychiatric disorders was consistently higher among patients with dementia compared with control participants and began to increase from 3 years before diagnosis (hazard ratio, [HR], 1.72; 95% CI, 1.67-1.76), peaked during the week after diagnosis (HR, 4.74; 95% CI, 4.21-5.34), and decreased rapidly thereafter. Decreased risk relative to controls was observed from 5 years after diagnosis (HR, 0.93; 95% CI, 0.87-0.98). The results were similar for Alzheimer disease, mixed dementia, vascular dementia and unspecified dementia. Among patients with dementia, markedly elevated use of psychiatric medications was observed in the year leading up to the dementia diagnosis and peaked 6 months after diagnosis. For example, antidepressant use was persistently higher among patients with dementia compared with controls, and the difference increased from 2 years before dementia diagnosis (15.9% vs 7.9%, P < .001), peaked approximately 6 months after dementia diagnosis (29.1% vs 9.7%, P < .001), and then decreased slowly from 3 years after diagnosis but remained higher than controls 5 years after diagnosis (16.4% vs 6.9%, P < .001).

Conclusions and Relevance

The findings of this cohort study that patients with dementia had markedly increased risks of psychiatric disorders both before and after dementia diagnosis highlight the significance of incorporating psychiatric preventative and management interventions for individuals with dementia across various diagnostic stages.

A systematic review of the prevalence of depression, anxiety, and apathy in frontotemporal dementia, atypical and young-onset Alzheimer's disease, and inherited dementia

OBJECTIVES

Depression, anxiety, and apathy are the most commonly reported neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD). Understanding their prevalence in rarer dementias such as frontotemporal dementia (FTD), primary progressive aphasia (PPA), posterior cortical atrophy (PCA), young-onset AD (YOAD), and inherited dementias has implications for both clinical practice and research. In this study, we aimed to examine the current state of knowledge of the prevalence of these three NPS in less prevalent dementias.

DESIGN

We conducted a systematic review based on searches of EMBASE, PsycINFO, and PubMed up to September 2019.

RESULTS

47 articles meeting inclusion criteria were identified. Depression, anxiety, and apathy were commonly reported across the phenotypes studied but their prevalence showed large variation between studies. Apathy showed the highest reported frequency in FTD (50-100% across studies), behavioral variant frontotemporal dementia (bvFTD) (73-100%), and YOAD (44-100%). Anxiety was frequently reported in FTD (0-100%) and bvFTD (19-63%). Depression showed the highest prevalence in FTD (7-69%) and YOAD (11-55%). Among the three variants of PPA, sv-PPA is the one most investigated (seven articles). Three or fewer articles were identified examining NPS in the remaining PPA variants, PCA, familial AD, and familial FTD. Inconsistency in the tools used to measure symptoms and small sample sizes were common methodological limitations.

CONCLUSIONS

Future studies should consider the inclusion of larger sample sizes (e.g. through multicenter collaborations) and the use of harmonized protocols that include the combination of caregiver and patient-derived measures and symptom-specific questionnaires. More research is needed on the phenotype-specific barriers and facilitators for people living with dementia to successfully engage in self-reports of NPS.

External Causes of Death From Death Certificates in Patients With Dementia

OBJECTIVES

We aim to analyze the risk of death from specific external causes, including falls, complications of medical and surgical care, unintentional injuries, and suicide, in dementia patients.

DESIGN

Swedish nationwide cohort study integrating 6 registers from May 1, 2007, through December 31, 2018, including the Swedish Registry for Cognitive/Dementia Disorders (SveDem).

SETTING AND PARTICIPANTS

Population-based study. Patients diagnosed with dementia from 2007 to 2018 and up to 4 controls matched on year of birth (±3 years), sex, and region of residence.

METHODS

The exposures of this study were diagnosis of dementia and dementia subtypes. Number of deaths and causes of mortality were obtained from death certificates compiled into the Cause of Death Register. Hazard ratios (HRs) and 95% CIs were estimated using Cox and flexible models, adjusted for sociodemographics, medical and psychiatric disorders.

RESULTS

The study population included 235,085 patients with dementia [96,760 men (41.2%); mean age 81.5 (SD 8.5) years] and 771,019 control participants [341,994 men (44.4%); mean age 79.9 (SD 8.6) years], over 3,721,687 person-years. Compared with control participants, patients with dementia presented increased risk for unintentional injuries (HR 3.30, 95% CI 3.19-3.40) and falls (HR 2.67, 95% CI 2.54-2.80) during old age (≥75 y), and suicide (HR 1.56, 95% CI 1.02-2.39) in middle age (<65 y). Suicide risk was 5.04 times higher (HR 6.04, 95% CI 4.22-8.66) in patients with both dementia and 2 or more psychiatric disorders relative to controls (incidence rate per person-years, 1.6 vs 0.3). For dementia subtypes, frontotemporal dementia had the highest risks of unintentional injuries (HR 4.28, 95% CI 2.80-6.52) and falls (HR 3.83, 95% CI 1.98-7.41), whereas subjects with mixed dementia were less likely to die from suicide (HR 0.11, 95% CI 0.03-0.46) and complications of medical and surgical care (HR 0.53, 95% CI 0.40-0.70) compared to controls.

CONCLUSIONS AND IMPLICATIONS

Suicide risk screening and psychiatric disorders management in early-onset dementia and early interventions for unintentional injuries and falls prevention in older dementia patients should be provided.

Neurocognitive markers of passive suicidal ideation in late-life depression

OBJECTIVES

(1) To delineate whether cognitive flexibility and inhibitory ability are neurocognitive markers of passive suicidal ideation (PSI), an early stage of suicide risk in depression and (2) to determine whether PSI is associated with volumetric differences in regions of the prefrontal cortex (PFC) in middle-aged and older adults with depression.

DESIGN

Cross-sectional study.

SETTING

University medical school.

PARTICIPANTS

Forty community-dwelling middle-aged and older adults with depression from a larger study of depression and anxiety (NIMH R01 MH091342-05 PI: O'Hara).

MEASUREMENTS

Psychiatric measures were assessed for the presence of a DSM-5 depressive disorder and PSI. A neurocognitive battery assessed cognitive flexibility, inhibitory ability, as well as other neurocognitive domains.

RESULTS

The PSI group (n = 18) performed significantly worse on cognitive flexibility and inhibitory ability, but not on other neurocognitive tasks, compared to the group without PSI (n = 22). The group with PSI had larger left mid-frontal gyri (MFG) than the no-PSI group. There was no association between cognitive flexibility/inhibitory ability and left MFG volume.

CONCLUSIONS

Findings implicate a neurocognitive signature of PSI: poorer cognitive flexibility and poor inhibitory ability not better accounted for by other domains of cognitive dysfunction and not associated with volumetric differences in the left MFG. This suggests that there are two specific but independent risk factors of PSI in middle- and older-aged adults.

Anticipated suicidal and death ideation in response to an imagined dementia diagnosis: A qualitative study

Alzheimer's disease and related dementias are prevalent, highly impactful, and feared diagnoses. A mixed methods study using semi-structured interviews was conducted to clarify causes of dementia-related anxiety. Fifty community-dwelling adults aged 58 to 89 (M = 70.92, SD = 6.08) were recruited from a university participant registry and Memory Clinic; none had dementia diagnoses. Analyses revealed that 42% (n = 21) of participants anticipated suicidal or death ideation if diagnosed with dementia. Among participants endorsing anticipated suicidal or death ideation, responses ranged from active, specific plans, including interest in physician-assisted suicide, to more passive wishes to hasten death rather than continue to live with dementia. Within reports of both anticipated suicidal and death ideation, three subthemes emerged. Participants reported concerns about becoming a burden to others, the devaluation of life/loss of self with dementia, and the desire for (and anticipated thwarting of) personal control as factors contributing to their anticipated responses to a dementia diagnosis. Statements of anticipated suicidal and death ideation were contingent on a dementia diagnosis and may reflect errors in affective forecasting. Nevertheless, given the prevalence of dementias and older adults' elevated rates of suicide, the intersection of these two public health issues warrants greater attention.

Subjective cognitive difficulties and posttraumatic stress disorder interact to increase suicide risk among middle-aged and older US military veterans

OBJECTIVES

To examine the role of subjective cognitive difficulties (SCD), posttraumatic stress disorder (PTSD), and their interaction in predicting suicidal ideation and current suicidal intent in middle-aged and older United States (US) military veterans.

DESIGN

Population-based cross-sectional study.

SETTING AND PARTICIPANTS

Data were analyzed from the 2019 to 2020 National Health and Resilience in Veterans Study, which surveyed a nationally representative sample of 3602 US veterans aged 50 years and older (mean age = 69.0).

MEASUREMENTS

Questionnaires including the Medical Outcomes Study Cognitive Functioning Scale (SCD), PTSD Checklist for DSM-5 (PTSD), Patient Health Questionnaire-9 (suicidal ideation in the previous two weeks), and the Suicide Behaviors Questionnaire-Revised (current suicidal intent).

RESULTS

A total of 154 (4.4%) veterans screened positive for current PTSD, 239 (6.7%) reported past two-week suicidal ideation, and 37 (1.0%) reported current suicidal intent. The probability of suicidal ideation among veterans with both SCD and PTSD was more than six times higher than that observed in the full sample (44.5% vs. 6.7%) and more than 2.5 times higher than that observed in veterans with SCD and no PTSD (44.5% vs. 17.5%). Veterans with both subjective memory and concentration difficulties were more likely to report suicidal intent, though the interaction between SCD and PTSD was not significantly associated with suicidal intent.

CONCLUSION

Middle-aged and older U.S. veterans with subjective cognitive impairment and PTSD report higher rates of suicidal ideation than those with SCD alone. Interventions targeting SCD and PTSD may mitigate suicide risk among middle-aged and older veterans.

Our dementia challenge: arise palliative care

While many of the maladies of the 20th century are steadily coming under control, the march of neurodegenerative disorders continues largely unchecked. Dementias are an exemplar of such disorders; their incidence and prevalence continue to rise, in large part due to a steadily ageing population worldwide. They represent a group of chronic, progressive and, ultimately, fatal neurodegenerative diseases. Dementia has remained therapeutically recalcitrant. It is not a single disease, and because of that, we cannot expect a single panacea. While primary prevention rightly gains prominence, those with established disease currently require a shift in focus from curative intent towards improved quality of life. Enter palliative care. The sheer number and complexity of needs of patients with dementia, from the physical to the psychosocial and spiritual, necessitates the engagement of a wide range of medical disciplines, nursing and allied health professionals. One of those disciplines, as highlighted in the recent Australian Royal Commission into Aged Care Quality and Safety, is palliative care. This paper shall expand upon that role in the overall context of care for those with dementia.

Pharmacogenetics of anxiety and depression in Alzheimer's disease

Anxiety and depression coexist with cognitive impairment in Alzheimer's disease along with other concomitant disorders (>60%), which require multipurpose treatments. Polypharmaceutical regimens cause drug-drug interactions and adverse drug reactions, potentially avoidable in number and severity with the implementation of pharmacogenetic procedures. The accumulation of defective variants (>30 genes per patient in more than 50% of cases) in pharmagenes (pathogenic, mechanistic, metabolic, transporter, pleiotropic) influences the therapeutic response to antidementia, antidepressant and anxiolytic drugs in polyvalent regimens. APOE, CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, CYP3A5, CYP4F2, COMT, MAOB, CHAT, GSTP1, NAT2, SLC30A8, SLCO1B1, ADRA2A, ADRB2, BCHE, GABRA1, HMGCR, HTR2C, IFNL3, NBEA, UGT1A1, ABCB1, ABCC2, ABCG2, SLC6A2, SLC6A3, SLC6A4, MTHFR and OPRM1 variants affect anxiety and depression in Alzheimer's disease.

Bipolar Disorder and Manic-Like Symptoms in Alzheimer's, Vascular and Frontotemporal Dementia: A Systematic Review

BACKGROUND

An increased risk of manic episodes has been reported in patients with neurodegenerative disorders, but the clinical features of bipolar disorder (BD) in different subtypes of dementia have not been thoroughly investigated.

OBJECTIVES

The main aim of this study is to systematically review clinical and therapeutic evidence about manic syndromes in patients with Alzheimer's disease (AD), vascular dementia (VaD), and frontotemporal dementia (FTD). Since manic-mixed episodes have been associated to negative outcomes in patients with dementia and often require medical intervention, we also critically summarized selected studies with relevance for the treatment of mania in patients with cognitive decline.

METHODS

A systematic review of the literature was conducted according to PRISMA guidelines. PubMed, Scopus, and Web of Science databases were searched up to February 2022. Sixty-one articles on patients with AD, VaD, or FTD and BD or (hypo) mania have been included.

RESULTS

Manic symptoms seem to be associated to disease progression in AD, have a greatly variable temporal relationship with cognitive decline in VaD, and frequently coincide with or precede cognitive impairment in FTD. Overall, mood stabilizers, and electroconvulsive therapy may be the most effective treatments, while the benefits of short-term treatment with antipsychotic agents must be balanced with the associated risks. Importantly, low-dose lithium salts may exert neuroprotective activity in patients with AD.

CONCLUSION

Prevalence, course, and characteristics of manic syndromes in patients with dementia may be differentially affected by the nature of the underlying neurodegenerative conditions.

Risk of Suicide After Dementia Diagnosis

Importance

Patients with dementia may be at an increased suicide risk. Identifying groups at greatest risk of suicide would support targeted risk reduction efforts by clinical dementia services.

Objectives

To examine the association between a dementia diagnosis and suicide risk in the general population and to identify high-risk subgroups.

Design, Setting, and Participants

This was a population-based case-control study in England conducted from January 1, 2001, through December 31, 2019. Data were obtained from multiple linked electronic records from primary care, secondary care, and the Office for National Statistics. Included participants were all patients 15 years or older and registered in the Office for National Statistics in England with a death coded as suicide or open verdict from 2001 to 2019. Up to 40 live control participants per suicide case were randomly matched on primary care practice and suicide date.

Exposures

Patients with codes referring to a dementia diagnosis were identified in primary care and secondary care databases.

Main Outcomes and Measures

Odds ratios (ORs) were estimated using conditional logistic regression and adjusted for sex and age at suicide/index date.

Results

From the total sample of 594 674 patients, 580 159 (97.6%) were controls (median [IQR] age at death, 81.6[72.0-88.4] years; 289 769 male patients [50.0%]), and 14 515 (2.4%) died by suicide (median [IQR] age at death, 47.4 [36.0-59.7] years; 10 850 male patients [74.8%]). Among those who died by suicide, 95 patients (1.9%) had a recorded dementia diagnosis (median [IQR] age at death, 79.5 [67.1-85.5] years; median [IQR] duration of follow-up, 2.3 [1.0-4.4] years). There was no overall significant association between a dementia diagnosis and suicide risk (adjusted OR, 1.05; 95% CI, 0.85-1.29). However, suicide risk was significantly increased in patients diagnosed with dementia before age 65 years (adjusted OR, 2.82; 95% CI, 1.84-4.33), in the first 3 months after diagnosis (adjusted OR, 2.47; 95% CI, 1.49-4.09), and in patients with dementia and psychiatric comorbidity (adjusted OR, 1.52; 95% CI, 1.21-1.93). In patients younger than 65 years and within 3 months of diagnosis, suicide risk was 6.69 times (95% CI, 1.49-30.12) higher than in patients without dementia.

Conclusions and Relevance

Diagnostic and management services for dementia, in both primary and secondary care settings, should target suicide risk assessment to the identified high-risk groups.

Suicidal Ideation and Suicide-Attempt-Related Hospitalizations among People with Alzheimer’s Disease (AD) and AD-Related Dementias in the United States during 2016–2018

People living with Alzheimer’s disease (AD) and AD-related dementias (ADRDs) are at a higher risk of suicidal behaviors given intersecting risk factors. Previous studies generally only focused on AD, small clinical samples, or grouped all dementia subtypes together, limiting insights for other ADRD subtypes. The objective of this study was to generate evidence related to the relative burden of suicidal behaviors (suicidal ideation and suicide attempt) among people with AD and ADRDs. This retrospective cross-sectional study identified hospitalizations related to suicidal behaviors (suicidal ideation and suicide attempt) for patients with Alzheimer’s disease (AD) and AD-related dementias using ICD-10-CM codes from the Nationwide Readmissions Database (NRD). A logistic regression model was estimated to assess associations between AD/ADRD subtype and patient characteristics, and the risk for a suicidal-behavior-related hospitalization and modes of harm were reported. During 2016–2018, there were 12,538 hospitalizations related to suicidal behaviors for people with AD/ADRDs. The overall prevalence of suicidal-behavior-related hospitalizations was lowest for AD (0.8%) and highest for frontotemporal dementia (2.6%). Among hospitalizations for suicide attempts, the most common mode of harm was medications or drugs (89.2% of all attempts), followed by weapons (17.7%). We found that there was a difference in the frequency of suicidal-behavior-related hospitalizations among AD/ADRD hospitalized patients across dementia subtypes.

Suicide risk in first year after dementia diagnosis in older adults

INTRODUCTION

Receiving a diagnosis of Alzheimer's disease or related dementias (ADRD) can be a pivotal and stressful period. We examined the risk of suicide in the first year after ADRD diagnosis relative to the general geriatric population.

METHODS

We identified a national cohort of Medicare fee-for-service beneficiaries aged ≥ 65 years with newly diagnosed ADRD (n = 2,667,987) linked to the National Death Index.

RESULTS

The suicide rate for the ADRD cohort was 26.42 per 100,000 person-years. The overall standardized mortality ratio (SMR) for suicide was 1.53 (95% confidence interval [CI] = 1.42, 1.65) with the highest risk among adults aged 65 to 74 years (SMR = 3.40, 95% CI = 2.94, 3.86) and the first 90 days after ADRD diagnosis. Rural residence and recent mental health, substance use, or chronic pain conditions were associated with increased suicide risk.

DISCUSSION

Results highlight the importance of suicide risk screening and support at the time of newly diagnosed dementia, particularly for patients aged < 75 years.

Conceptualising comorbidity and multimorbidity in dementia: A scoping review and syndemic framework

Background

Older people and people with dementia experience a high prevalence of multiple health conditions. The terms ‘comorbidity’ and ‘multimorbidity’ are often used interchangeably to describe this, however there are key conceptual differences between these terms and their definitions. This has led to issues in the validity and comparability of research findings, potentially inappropriate intervention development and differences in quality of health care.

Objective

To review how the terms ‘comorbidity’ and ‘multimorbidity’ are defined within peer-reviewed dementia research and propose an operational framework.

Design

A scoping review of definitions within dementia research was carried out. Searches took place across five databases: Academic Search Premier, CINAHL Complete, MEDLINE, PsycARTICLES and PsycINFO. PRISMA-ScR guidelines were followed.

Results

Content analysis revealed five key themes, showing significant overlap and inconsistencies from both within, and between, the comorbidity and multimorbidity definitions; 1. Number of conditions; 2. Type of health conditions; 3. The co-occurrence of conditions; 4. The inclusion of an index disease (or not); 5. Use of medical language. The analysis also revealed gaps in how the underlying concepts of the definitions relate to people with dementia living with multiple health conditions.

Conclusion

This scoping review found that current definitions of comorbidity and multimorbidity are heterogeneous, reductionist and disease-focussed. Recommendations are made on the design of research studies including transparency and consistency of any terms and definitions used. A syndemic framework could be a useful tool for researchers, clinicians and policy makers to consider a more holistic picture of a person with dementia’s health and wellbeing.

Robin's Wish and the Complex Causal Web of Death by Suicide

The documentary film Robin's Wish aims to reclaim the media scrutiny around Robin Williams' death, fixating on causation being solely attributed to a postmortem diagnosis of which Williams was unaware-Lewy Body Dementia. The film and other sources as well defined and animated the view that Williams' death by suicide was fully a result of this medical condition, dismissing any possible role for mental disorders. The need to distance from mental disorders can have a palpable undercurrent of stigmatization of them; the documentary missed the opportunity to make its point and simultaneously build allyship with others who have lost someone to suicide who were clearly battling a mental disorder. In this context, we emphasize the importance of looking at causation mediationally (e.g., a neurological condition triggering a major depressive episode culminating, in turn, in death by suicide). Only through encompassing all elements and complexities of the human spirit and condition can we appropriately pay tribute to those we have lost to suicide and simultaneously de-stigmatize mental disorders.

Associated factors of suicidal ideation among older persons with dementia living at home in eight European countries

OBJECTIVES

This study aimed to investigate the occurrence of suicidal ideation and associated factors in older persons with dementia living at home in eight European countries, and its association with quality of life. Furthermore, changes in suicidal ideation over time were investigated.

METHODS

This cohort study (n = 1,223) was part of the European "RightTimePlaceCare" project conducted in 2010-2013. Participating countries were Estonia, Finland, France, Germany, the Netherlands, Spain, Sweden and the United Kingdom. Baseline and follow-up data were analysed using bivariate and multivariate logistic regression.

RESULTS

The occurrence of suicidal ideation in the participating countries varied between 6% and 24%. Factors significantly (p < 0.0018) associated with suicidal ideation using bivariate analysis were: nationality, depressive symptoms, delusions, hallucinations, agitation, anxiety, apathy, disinhibition, irritability, night-time behaviour disturbances, anxiolytics and anti-dementia medication. In the multivariate regression analysis, country of origin, moderate stage of the dementia, depressive and delusional symptoms, and anti-dementia medication were significantly associated with suicidal ideation (p < 0.05). Over time, suicidal ideation decreased from severe to mild or became absent in 54% of the persons with dementia.

CONCLUSION

It is essential that professionals identify older persons with dementia and suicidal ideation and depressive and other psychological symptoms in order to give them appropriate treatment and provide relief for their informal caregivers. We emphasize the importance of identifying suicidal ideation, irrespective of depressive symptoms, and specifically of paying attention to persons with moderate dementia. Living with the informal caregiver seems to be associated with staying stable without suicidal ideation.

Frequency of suicidal ideation and associated clinical features in Lewy body dementia

INTRODUCTION

Neuropsychiatric disturbance is common in individuals with Lewy body dementia (LBD). Despite this, there is minimal research regarding suicide risks in this population.

METHODS

This study was a retrospective review of a prospectively-collected database at a tertiary movement disorders clinic. Database participants with an LBD diagnosis at their most recent visit and at least one complete Beck Depression Inventory-II (BDI-II) were included. Additional measures included demographics and measures of cognition, psychiatric symptoms, motor function, and the Parkinson Disease Questionnaire-39. The frequency of suicidal ideation was assessed using question 9 of the BDI-II. Features associated with a BDI-II score greater than zero were assessed using logistic regression.

RESULTS

The database included 95 individuals with LBD and at least one BDI-II (visit years 2010-2020). Most participants were older men who identified as white. Eighteen individuals (18.9%; 95% CI 12.3%-28.0%) reported thoughts of killing themselves without an intent to carry them out (BDI-II = 1). No participants reported a desire or plan to kill themselves. The presence of SI was associated with measures of depression, anxiety, and emotional well-being, but not with demographics, measures of disease severity, or other psychiatric concerns.

CONCLUSION

These findings emphasize the importance of routine screening for psychiatric symptoms in LBD and intervention when such concerns are identified. Interventions could include pharmacologic (e.g. depression treatment) and non-pharmacologic (e.g. firearm screening) approaches. More research is needed to assess suicidal ideation and suicide risks in large and more diverse LBD populations. Prospective studies should include measures of additional potential contributors to suicidality.

Suicidal Ideations and Behavior in Patients With Young and Late Onset Dementia

Background and Objectives: Data on suicidal ideation, behavior and the risk factors in patients with dementia is scarce. To evaluate the prevalence of death wishes, suicidal ideation, and suicidal behavior of young (YOD) and late onset dementia (LOD) and to identify risk factors for suicidal ideation and behavior. Methods: We interviewed 157 family caregivers of patients with advanced dementia using questions from the Columbia-Suicide Severity Rating Scale to gather information about suicidal ideation and behavior before the onset of symptoms of dementia, after the onset of dementia and within 30 days prior to the interview. At the time of the interview, we also assessed disease severity, cognitive function, and other psychological, behavioral and physical symptoms of the patients as well as the caregivers' psychological well-being. Results: Forty four (28%) of the patients expressed suicidal ideation or behavior at some time after the onset of symptoms, and 14 (9%) of these within the month prior to the assessment. Two patients had attempted suicide after the onset of dementia. There were no statistically significant differences between patients with and without suicidal ideations or behavior with regards to demographics or age at onset of dementia. In patients with advanced dementia, Alzheimer's disease (rather than frontotemporal lobar degeneration), better cognitive function, more severe psychological, behavioral, and physical symptoms, and a reduced quality of life were associated with the expression of suicidal ideation. Conclusions: According to caregivers' reports, majority of patients with dementia did not express suicidal ideation or show suicidal behavior. Patients who expressed suicidal ideation during early stages of dementia often stopped expressing them in advanced stages. It remains unclear if this was due to reduced communication abilities, a reduction of disease awareness, and/ or an adjustment to their situation.

Risk of Suicide Attempt in Patients With Recent Diagnosis of Mild Cognitive Impairment or Dementia

IMPORTANCE

Little is known about the association between mild cognitive impairment (MCI) and suicide. Most studies have focused on dementia and suicidal behavior, with inconsistent results.

OBJECTIVES

To examine the association between diagnoses of MCI and dementia and suicide attempt and explore potential psychiatric moderators and to assess whether the association differs based on recency of diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

This nationwide cohort study integrated 5 national databases from the Department of Veterans Affairs (VA) and Centers for Medicare & Medicaid Services and included all VA medical centers in the US. US veterans 50 years or older with MCI diagnoses at baseline (October 1, 2011, to September 30, 2013) or earlier (October 1, 2007, to September 30, 2011) were propensity matched 1:3 with (1) patients with dementia diagnoses and (2) patients without either diagnosis based on demographic characteristics and the Charlson Comorbidity Index. Diagnoses of MCI or dementia were defined as recent if there were no diagnosis codes before baseline. Data were analyzed from March 16, 2020, to January 15, 2021.

MAIN OUTCOMES AND MEASURES

Information on suicide attempts through December 31, 2016, provided by the National Suicide Prevention Applications Network (nonfatal) and Mortality Data Repository (fatal).

RESULTS

The study population of 147 595 participants included 21 085 patients with MCI, 63 255 with dementia, and 63 255 in the propensity-matched comparison group. Participants had a mean (SD) age of 74.7 (10.3) years, 143 353 (97.1%) were men, 4242 (2.9%) were women, and 127 065 (86.1%) were non-Hispanic White. A total of 138 patients with MCI (0.7%) and 400 patients with dementia (0.6%) attempted suicide during follow-up, compared with 253 patients without MCI or dementia (0.4%). Exploratory analyses revealed that no psychiatric comorbidity moderated the association between MCI or dementia and suicide attempt. After adjustment for demographic details and medical and psychiatric comorbidities, risk of suicide attempt was consistently highest for patients with a recent MCI or dementia diagnosis, with adjusted hazard ratios (HRs) of 1.73 (95% CI, 1.34-2.22; P < .001) for recent MCI and 1.44 (95% CI, 1.17-1.77; P = .001) for recent dementia. Risk associated with prior diagnosis was not significant (HR for prior MCI, 1.03 [95% CI, 0.78-1.36; P = .84]; HR for prior dementia, 1.14 [95% CI, 0.95-1.36; P = .15]).

CONCLUSIONS AND RELEVANCE

This study found that older adults with recent MCI or dementia diagnoses were at increased risk of attempting suicide. These findings suggest that involvement of supportive services at the time of or soon after diagnoses of MCI or dementia may help mitigate risk of suicide attempts.

Search for solutions, learning, simulation, and choice processes in suicidal behavior

Suicide may be viewed as an unfortunate outcome of failures in decision processes. Such failures occur when the demands of a crisis exceed a person's capacity to (i) search for options, (ii) learn and simulate possible futures, and (iii) make advantageous value‐based choices. Can individual‐level decision deficits and biases drive the progression of the suicidal crisis? Our overview of the evidence on this question is informed by clinical theory and grounded in reinforcement learning and behavioral economics. Cohort and case–control studies provide strong evidence that limited cognitive capacity and particularly impaired cognitive control are associated with suicidal behavior, imposing cognitive constraints on decision‐making. We conceptualize suicidal ideation as an element of impoverished consideration sets resulting from a search for solutions under cognitive constraints and mood‐congruent Pavlovian influences, a view supported by mostly indirect evidence. More compelling is the evidence of impaired learning in people with a history of suicidal behavior. We speculate that an inability to simulate alternative futures using one's model of the world may undermine alternative solutions in a suicidal crisis. The hypothesis supported by the strongest evidence is that the selection of suicide over alternatives is facilitated by a choice process undermined by randomness. Case–control studies using gambling tasks, armed bandits, and delay discounting support this claim. Future experimental studies will need to uncover real‐time dynamics of choice processes in suicidal people. In summary, the decision process framework sheds light on neurocognitive mechanisms that facilitate the progression of the suicidal crisis.

This article is categorized under:

Economics > Individual Decision‐Making

Psychology > Emotion and Motivation

Psychology > Learning

Neuroscience > Behavior

Influence of Pathogenic and Metabolic Genes on the Pharmacogenetics of Mood Disorders in Alzheimer's Disease

Background: Mood disorders represent a risk factor for dementia and are present in over 60% of cases with Alzheimer’s disease (AD). More than 80% variability in drug pharmacokinetics and pharmacodynamics is associated with pharmacogenetics. Methods: Anxiety and depression symptoms were assessed in 1006 patients with dementia (591 females, 415 males) and the influence of pathogenic (APOE) and metabolic (CYP2D6, CYP2C19, and CYP2C9) gene variants on the therapeutic outcome were analyzed after treatment with a multifactorial regime in a natural setting. Results and Conclusions: (i) Biochemical, hematological, and metabolic differences may contribute to changes in drug efficacy and safety; (ii) anxiety and depression are more frequent and severe in females than males; (iii) both females and males respond similarly to treatment, showing significant improvements in anxiety and depression; (iv) APOE-3 carriers are the best responders and APOE-4 carriers tend to be the worst responders to conventional treatments; and (v) among CYP2D6, CYP2C19, and CYP2C9 genophenotypes, normal metabolizers (NMs) and intermediate metabolizers (IMs) are significantly better responders than poor metabolizers (PMs) and ultra-rapid metabolizers (UMs) to therapeutic interventions that modify anxiety and depression phenotypes in dementia. APOE-4 carriers and CYP-related PMs and UMs deserve special attention for their vulnerability and poor response to current treatments.

Severe Suicidality in Athletes with Chronic Traumatic Encephalopathy: A Case Series and Overview on Putative Ethiopathogenetic Mechanisms

Chronic traumatic encephalopathy (CTE) results from repetitive brain injuries and is a common neurotraumatic sequela in contact sports. CTE is often accompanied by neuropsychiatric symptoms, which could escalate to suicidal ideation (SI) and suicidal behaviour (SB). Nevertheless, fairly limited emphasis about the association between suicidality and CTE exists in medical literature. Here, we report two cases of retired professional athletes in high contact sports (boxing and ice hockey) who have developed similar clinical trajectories characterized by progressive neuropsychiatric symptoms compatible with a CTE diagnosis and subsequent SB in its severe forms (medical serious suicide attempt (SA) and completed suicide). In addition to the description of outlining clinical, neuropsychological, neuroimaging, and differential diagnosis elements related to these cases, we also hypothesized some mechanisms that might augment the suicide risk in CTE. They include those related to neurobiological (neuroanatomic/neuroinflammatory) dysfunctions as well as those pertaining to psychiatry and psychosocial maladaptation to neurotraumas and retirement from professional competitive activity. Findings described here can provide clinical pictures to improve the identification of patients with CTE and also potential mechanistic insights to refine the knowledge of eventual severe SB development, which might enable its earlier prevention.

Suicide risk within 1 year of dementia diagnosis in older adults: a nationwide retrospective cohort study

BACKGROUND

Although severe dementia could protect against suicide death by decreasing a person's capacity to implement a suicide plan, patients with early dementia may have better cognition, giving them more sustained insight into their disease and better enabling them to carry out a suicide plan. This study investigated suicide risk in older adults within 1 year of receiving a diagnosis of dementia.

METHODS

This study used National Health Insurance Service Senior Cohort data and included 36 541 older adults with newly diagnosed dementia (a Mini-Mental State Examination score ≤ 26 and a Clinical Dementia Rating score ≥ 1 or a Global Deterioration Scale score ≥ 3), including Alzheimer disease, vascular dementia and other/unspecified dementia, from 2004 to 2012. We selected older adults without dementia through 1:1 propensity-score matching using sex, age, comorbidities and index year, with follow-up throughout 2013. We estimated adjusted hazard ratios (AHRs) of suicide deaths within 1 year after diagnosis using a time-dependent Cox proportional hazards model.

RESULTS

We verified 46 suicide deaths during the first year after a dementia diagnosis. Older adults with dementia had an increased risk of suicide death compared to those without dementia (AHR 2.57; 95% confidence interval [CI] 1.49-4.44). Older adults with Alzheimer disease (AHR 2.50; 95% CI 1.41-4.44) or other/unspecified dementia (AHR 4.32; 95% CI 2.04-9.15) had an increased risk of suicide death compared to those without dementia. Patients with dementia but without other mental disorders (AHR 1.96; 95% CI 1.02-3.77) and patients with dementia and other mental disorders (AHR 3.22; 95% CI 1.78-5.83) had an increased risk of suicide death compared to patients without dementia. Patients with dementia and schizophrenia (AHR 8.73; 95% CI 2.57-29.71), mood disorders (AHR 2.84; 95% CI 1.23-6.53) or anxiety or somatoform disorders (AHR 3.53; 95% CI 1.73-7.21), respectively, had an increased risk of suicide death compared to patients with those conditions but without dementia.

LIMITATIONS

This study examined only elderly patients in South Korea, a population with a substantially higher suicide rate than the global population. Caution must be exercised when generalizing the results to populations with dissimilar backgrounds.

CONCLUSION

Patients with dementia had an increased risk of suicide death within 1 year after diagnosis compared to those without dementia.

Degenerative dementias: Alterations of emotions and mood disorders

Degenerative dementias such as Alzheimer's disease and frontotemporal dementia result in distinct alterations in emotional processing, emotional experiences, and mood. The neuropathology of these dementias extends to structures involved in emotional processing, including the basolateral limbic network (orbitofrontal cortex, anterior temporal lobe, amygdala, and thalamus), the insula, and ventromedial frontal lobe. Depression is the most common emotion and mood disorder affecting patients with Alzheimer's disease. The onset of depression can be a prodromal sign of this dementia. Anxiety can also be present early in the course of Alzheimer's disease and especially among patients with early-onset forms of the disease. In contrast, patients with behavioral variant frontotemporal dementia demonstrate hypoemotionality, deficits in the recognition of emotion, and decreased psychophysiological reactivity to emotional stimuli. They typically have a disproportionate impairment in emotional and cognitive empathy. One other unique feature of behavioral variant frontotemporal dementia is the frequent occurrence of bipolar disorder. The management strategies for these alterations of emotion and mood in degenerative dementias primarily involve the judicious use of the psychiatric armamentarium of medications.

Mental Disorders, Cognitive Impairment and the Risk of Suicide in Older Adults

More than 600 million people are aged 60 years and over are living in the world. The World Health Organization estimates that this number will double by 2025 to 2 billion older people. Suicide among people over the age of 60 is one of the most acute problems. The factors strongly associated with suicide are mentioned: physical illnesses, such as cancer, neurologic disorder, pain, liver disease, genital disorders, or rheumatoid disorders. Moreover, neurologic conditions, especially stroke, may affect decision-making processes, cognitive capacity, and language deficit. In addition to dementia, the most common mental disorders are mood and anxiety disorders. A common symptom of these disorders in the elderly is cognitive impairment. This study aimed to present the relationship between cognitive impairment due to dementia, mood disorders and anxiety, and an increased risk of suicide among older people. Dementia is a disease where the risk of suicide is significant. Many studies demonstrated that older adults with dementia had an increased risk of suicide death than those without dementia. Similar conclusions apply to prodromal dementia Depression is also a disease with a high risk of suicide. Many researchers found that a higher level of depression was associated with suicide attempts and suicide ideation. Bipolar disorder is the second entity in mood disorders with an increased risk of suicide among the elderly. Apart from suicidal thoughts, bipolar disorder is characterized by high mortality. In the group of anxiety disorders, the most significant risk of suicide occurs when depression is present. In turn, suicide thoughts are more common in social phobia than in other anxiety disorders. Suicide among the elderly is a serious public health problem. There is a positive correlation between mental disorders such as dementia, depression, bipolar disorder, or anxiety and the prevalence of suicide in the elderly. Therefore, the elderly should be comprehensively provided with psychiatric and psychological support.

Perspectives of Veterans Affairs mental health providers on working with older adults with dementia and their caregivers

Continuing education directed at building providers' skills and knowledge in geriatrics represents a practical approach to addressing the geriatric mental health (MH) care workforce shortage. To inform the development of professional training curricula, we surveyed MH providers (N = 65) at a Veterans Affairs medical center on working with older persons with dementia (PwD) and informal caregivers. Providers rated service provision to PwD and caregivers as highly important but endorsed modest self-efficacy. Half of respondents were minimally confident in managing risk of harm to self or others in a PwD. Respondents believed PwD can benefit from MH treatments, yet identified several barriers to providing care, including inadequate time and staffing resources. Interest in geriatric training topics was high. Findings demonstrate that MH providers at this site value care provision to PwD and caregivers, and desire additional training to serve this population. System-level barriers to MH care for PwD should also be identified and addressed.

Bipolar Disorder Among Patients Diagnosed With Frontotemporal Dementia

OBJECTIVE

Previous studies have documented manic and hypomanic symptoms in behavioral variant frontotemporal dementia (bvFTD), suggesting a relationship between bipolar disorder and bvFTD.

METHODS

The investigators conducted a literature review as well as a review of the psychiatric histories of 137 patients with bvFTD, and patients with a prior diagnosis of bipolar disorder were identified. The clinical characteristics of patients' bipolar disorder diagnosis, family history, features of bvFTD, and results from fluorodeoxyglucose positron emission tomography (FDG-PET), as well as autopsy findings, were evaluated.

RESULTS

Among the 137 patients, 14 (10.2%) had a psychiatric diagnosis of bipolar disorder, eight of whom met criteria for bipolar disorder (type I, N=6; type II, N=2) 6-12 years preceding onset of classic symptoms of progressive bvFTD. Seven of the eight patients with bipolar disorder had a family history of mood disorders, four had bitemporal predominant hypometabolism on FDG-PET, and two had a tauopathy involving temporal lobes on autopsy. Three additional patients with late-onset bipolar I disorder proved to have a nonprogressive disorder mimicking bvFTD. The remaining three patients with bvFTD had prior psychiatric symptoms that did not meet criteria for a diagnosis of bipolar disorder. The literature review and the findings for one patient further suggested a shared genetic mutation in some patients.

CONCLUSIONS

Manic or hypomanic episodes years before other symptoms of bvFTD may be a prodrome of this dementia, possibly indicating anterior temporal involvement in bvFTD. Other patients with late-onset bipolar disorder exhibit the nonprogressive frontotemporal dementia phenocopy syndrome. Finally, a few patients with bvFTD have a genetic predisposition for both disorders.

Pharmacogenomics of Cognitive Dysfunction and Neuropsychiatric Disorders in Dementia

Symptomatic interventions for patients with dementia involve anti-dementia drugs to improve cognition, psychotropic drugs for the treatment of behavioral disorders (BDs), and different categories of drugs for concomitant disorders. Demented patients may take >6–10 drugs/day with the consequent risk for drug–drug interactions and adverse drug reactions (ADRs >80%) which accelerate cognitive decline. The pharmacoepigenetic machinery is integrated by pathogenic, mechanistic, metabolic, transporter, and pleiotropic genes redundantly and promiscuously regulated by epigenetic mechanisms. CYP2D6, CYP2C9, CYP2C19, and CYP3A4/5 geno-phenotypes are involved in the metabolism of over 90% of drugs currently used in patients with dementia, and only 20% of the population is an extensive metabolizer for this tetragenic cluster. ADRs associated with anti-dementia drugs, antipsychotics, antidepressants, anxiolytics, hypnotics, sedatives, and antiepileptic drugs can be minimized by means of pharmacogenetic screening prior to treatment. These drugs are substrates, inhibitors, or inducers of 58, 37, and 42 enzyme/protein gene products, respectively, and are transported by 40 different protein transporters. APOE is the reference gene in most pharmacogenetic studies. APOE-3 carriers are the best responders and APOE-4 carriers are the worst responders; likewise, CYP2D6-normal metabolizers are the best responders and CYP2D6-poor metabolizers are the worst responders. The incorporation of pharmacogenomic strategies for a personalized treatment in dementia is an effective option to optimize limited therapeutic resources and to reduce unwanted side-effects.

Etiopathogenesis of Suicide: A Conceptual Analysis of Risk and Prevention Within a Comprehensive, Deterministic Model

Suicide is a rising global health concern receiving disproportionate attention in comparison to other health conditions. In spite of substantial technological and scientific advancements, suicide research has continued to move slowly in terms of clinical translation due to the complexity of neural mechanisms, and subjective experiences that seem to underpin this complex human behavior. This paper analyzes the concepts of risk and prevention in the context of suicide in an attempt to bridge the large methodological and theoretical gaps between the biological, psychological, and sociological dimensions. This paper aims to accomplish the following objectives: (1) operationalize the concepts of suicide risk and prevention as they relate to current knowledge and capabilities; (2) synthesize and integrate suicide research across biological, psychological, and sociological dimensions; (3) discuss limitations of each dimension in isolation; (4) suggest a model of etiopathogenesis that incorporates extant literature and bridges unnecessary gaps between dimensions; and (5) suggest future directions for multidimensional research through the inclusion of principles from the physical sciences. Ultimately, this paper provides a basis for a comprehensive model of suicide within a deterministic, chaotic system.

The Role of TDP-43 in Military-Relevant TBI and Chronic Neurodegeneration

Due largely to the use of improvised explosive devices (IEDs) and other explosives in recent military conflicts, blast-related TBI has emerged as a prominent injury sustained by warfighters. In the recent wars in Iraq and Afghanistan, traumatic brain injury (TBI) has been one of the most common types of injury sustained by soldiers and military personnel; of the ~380,000 TBIs reported in service members from 2000 to 2017, 82.3% were classified as mild (mTBI). While mTBI is associated with normal structural imaging, brief or no loss of consciousness, and rapid recovery of mental state, mTBI can nevertheless lead to persistent behavioral and cognitive effects. As in other cases of mTBI, exposure to low-level blast often does not cause immediate overt neurological effects, but may similarly lead to persistent behavioral and cognitive deficits. These effects are likely to be compounded when multiple exposures to blast and/or impact are sustained, since there is increasing evidence that multiple mTBIs can lead to chronic neurodegeneration. One common form of this deleterious outcome is frontotemporal lobar degeneration (FTLD), which is a progressive neurodegenerative process marked by atrophy of the frontal and temporal lobes, leading to frontotemporal dementia, a common form of dementia affecting behavior, cognition and language. About half of all cases of FTLD are marked by TAR-DNA binding protein (TDP-43)-positive protein inclusions. TDP-43, a DNA/RNA binding protein, controls the expression of thousands of genes and is associated with several neurodegenerative diseases including amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's disease, and chronic traumatic encephalopathy. TDP-43 abnormalities have also been associated with traumatic brain injury in both pre-clinical and clinical studies. The role of TDP-43 in the manifestation of FTLD pathology in military TBI cases is currently unclear, and to date there has been only a limited number of pre-clinical studies addressing the effects of repeated blast-related mild TBI (rbTBI) in relation to FTLD and TDP-43. This review will summarize some of these findings and address the concerns and critical knowledge gaps associated with FTLD manifestation with military populations, as well as clinical findings on other forms of mTBI.