Disease, contagious cannibalism, and associated population crash in an omnivorous bug, Geocoris pallens.

Disease and cannibalism are two strongly density-dependent processes that can suppress predator populations. Here we show that California populations of the omnivorous predatory bug Geocoris pallens are subject to infection by a pathogen, as yet unidentified, that elicits elevated expression of cannibalism. Laboratory experiments showed that the pathogen is moderately virulent, causing flattened abdomens, elevated nymphal mortality, delayed development, and reduced body size of adult females. Infection furthermore increases the expression of cannibalism. Field populations of Geocoris spp. declined strongly in association with sharp increases in the expression of egg cannibalism by adult G. pallens. Increased cannibalism was accompanied by a strongly bimodal distribution of cannibalism expression, with some females (putatively uninfected) expressing little cannibalism and others (putatively infected) consuming most or all of the eggs present. Highly cannibalistic females did not increase their consumption of Ephestia cautella moth eggs, suggesting that the high cannibalism phenotype reflected a specific loss of restraint against eating conspecifics. Highly cannibalistic females also often exhibited reduced egg laying, consistent with a virulent pathogen; less frequently, more cannibalistic females exhibited elevated egg laying, suggesting that cannibalism might also facilitate recycling of nutrients in eggs. Elevated cannibalism was not correlated with reduced prey availability or elevated field densities of G. pallens. Geocoris pallens population crashes appear to reflect the combined consequences of direct virulence-adverse pathogen effects on the infected host's physiology-and indirect virulence-mortality of both infected and uninfected individuals due to elevated cannibalism expression by infected individuals.

Association of Frailty With Risk of Suicide Attempt in a National Cohort of US Veterans Aged 65 Years or Older.

Importance: Frailty is associated with reduced physiological reserve, lack of independence, and depression and may be salient for identifying older adults at increased risk of suicide attempt. Objectives: To examine the association between frailty and risk of suicide attempt and how risk differs based on components of frailty. Design, Setting, and Participants: This nationwide cohort study integrated databases from the US Department of Veterans Affairs (VA) inpatient and outpatient health care services, Centers for Medicare & Medicaid Services data, and national suicide data. Participants included all US veterans aged 65 years or older who received care at VA medical centers from October 1, 2011, to September 30, 2013. Data were analyzed from April 20, 2021, to May 31, 2022. Exposures: Frailty, defined based on a validated cumulative-deficit frailty index measured using electronic health data and categorized into 5 levels: nonfrailty, prefrailty, mild frailty, moderate frailty, and severe frailty. Main Outcomes and Measures: The main outcome was suicide attempts through December 31, 2017, provided by the national Suicide Prevention Applications Network (nonfatal attempts) and Mortality Data Repository (fatal attempts). Frailty level and components of the frailty index (morbidity, function, sensory loss, cognition and mood, and other) were assessed as potential factors associated with suicide attempt. Results: The study population of 2 858 876 participants included 8955 (0.3%) who attempted suicide over 6 years. Among all participants, the mean (SD) age was 75.4 (8.1) years; 97.7% were men, 2.3% were women, 0.6% were Hispanic, 9.0% were non-Hispanic Black, 87.8% were non-Hispanic White, and 2.6% had other or unknown race and ethnicity. Compared with patients without frailty, risk of suicide attempt was uniformly higher among patients with prefrailty to severe frailty, with adjusted hazard ratios (aHRs) of 1.34 (95% CI, 1.27-1.42; P < .001) for prefrailty, 1.44 (95% CI, 1.35-1.54; P < .001) for mild frailty, 1.48 (95% CI, 1.36-1.60; P < .001) for moderate frailty, and 1.42 (95% CI, 1.29-1.56; P < .001) for severe frailty. Lower levels of frailty were associated with greater risk of lethal suicide attempt (aHR, 1.20 [95% CI, 1.12-1.28] for prefrail veterans). Bipolar disorder (aHR, 2.69; 95% CI, 2.54-2.86), depression (aHR, 1.78; 95% CI, 1.67-1.87), anxiety (aHR, 1.36; 95% CI, 1.28-1.45), chronic pain (aHR, 1.22; 95% CI, 1.15-1.29), use of durable medical equipment (aHR, 1.14; 95% CI, 1.03-1.25), and lung disease (aHR, 1.11; 95% CI, 1.06-1.17) were independently associated with increased risk of suicide attempt. Conclusions and Relevance: This cohort study found that among US veterans aged 65 years or older, frailty was associated with increased risk of suicide attempts and lower levels of frailty were associated with greater risk of suicide death. Screening and involvement of supportive services across the spectrum of frailty appear to be needed to help reduce risk of suicide attempts.

Posttraumatic stress disorder, suicide, and unintended overdose death in later life: A national cohort study of veterans aged 50 and older.

BACKGROUND/OBJECTIVES: Although studies have shown posttraumatic stress disorder (PTSD) associated with risk of suicide, the relationship in later life, especially for overdose death, remains unclear. Thus, the aim of the current study was to determine associations between PTSD, suicide, and unintended overdose death in mid- to late-life. METHODS: A nationwide cohort study integrating Department of Veterans Affairs' (VA) data, Centers for Medicare & Medicaid Services data, and national cause-specific mortality data. Participants were US veterans aged ≥50 years with PTSD diagnoses at baseline (2012-2013) and were propensity-matched 1:1 with patients without PTSD based on sociodemographics, Charlson Comorbidity Index, and neuropsychiatric disorders (N = 951,018). Information on suicide attempts and unintended death by overdose through December 31, 2017 was provided by the VA's National Suicide Prevention Applications Network (non-fatal attempts) and Mortality Data Repository (death). RESULTS: Veterans with PTSD (N = 475,509) had increased risk of suicide attempt (Hazard Ratio [HR], 1.59; 95% CI, 1.54-1.65; p < 0.001), non-fatal attempt (HR, 1.74; 95% CI, 1.67-1.81; p < 0.001), drug overdose death overall (HR, 1.32; 95% CI, 1.22-1.42; p < 0.001), and suicide overdose death (HR, 1.44; 95% CI, 1.15-1.80; p = 0.002), even after adjusting for sociodemographics, Charlson comorbidity index, and neuropsychiatric disorders. We found increased risk for overdose death by narcotics (HR, 1.30; 95% CI, 1.15-1.46; p < 0.001), antiepileptic/sedative-hypnotics (HR, 1.29; 95% CI, 1.02-1.62; p = 0.032), and for other/unspecified drugs (HR, 1.35; 95% CI, 1.20-1.51; p < 0.001), the last category indicative of polydrug. Results remained robust when examined for unintentional, suicide, and undetermined intent for cause-specific death by other/unspecified drugs. CONCLUSIONS: PTSD persists throughout mid- to late-life with considerable increased risk for non-fatal suicide attempts and suicide overdose death. These findings suggest the importance of drug-monitoring in preventing late-life suicide.

Prevalence of dementia and mild cognitive impairment before incarceration.

BACKGROUND: Accumulating evidence indicates that behaviors in Alzheimer's disease and related dementias could result in incarceration. Yet, the proportion of persons diagnosed with dementia and mild cognitive impairment (MCI) before they were incarcerated is largely unknown. By leveraging a national sample of mid- to late-life adults who were incarcerated, we determined the prevalence of dementia and MCI before their incarceration. METHODS: In this current study, participants were Medicare-eligible U.S. veterans who transitioned from incarceration to the community in mid- to late-life from October 1, 2012, to September 30, 2018, after having been incarcerated for ≤10 consecutive years (N = 17,962). Medical claims data were used to determine clinical diagnoses of dementia and MCI up to three years before incarceration. Demographics, comorbidities, and duration of incarceration among those with dementia and MCI were compared to those with neither diagnosis. RESULTS: Participants were >97% male, 65% non-Hispanic white, 30% non-Hispanic black, and 3.3% had a diagnosis of either dementia (2.5%) or MCI (0.8%) before their most recent incarceration. Individuals with MCI or dementia diagnoses were older, were more likely to be non-Hispanic white, had more medical and psychiatric comorbidities, and experienced homelessness and traumatic brain injury at higher rates than those with neither diagnosis. Average duration of incarceration was significantly shorter among those with MCI (201.8 [±248.0] days) or dementia (312.8 [±548.3] days), as compared to those with neither diagnosis (497.0 [±692.7] days) (p < 0.001). CONCLUSIONS: These findings raise awareness of the proportion of incarcerated persons in the United States who have a diagnosis of MCI or dementia before they are incarcerated. Improved understanding of pathways linking cognitive impairment to incarceration in mid- to late-life are needed to inform appropriateness of incarceration, optimization of health care, and prevention of interpersonal harm in this medically vulnerable population.