Abstract

Introduction:

Moral injury, the psychological harm resulting from events that violate one’s deeply held moral beliefs, has been extensively studied in military and healthcare populations but remains largely unexamined among animal care workers.

Methods:

This cross-sectional survey of 291 animal care workers across six sectors (rescue, shelter, animal control, veterinary medicine, volunteer/foster, and other) provides the first empirical prevalence estimate of moral injury in this cross-sector population using a validated syndrome measure.

Results:

Findings from the Moral Injury Outcome Scale (MIOS) indicate that 83.5% of participants endorsed at least one morally injurious experience pathway; most common was witnessing (63.9%), followed by being affected by others’ transgressions (38.5%) and direct participation (29.2%). Applying published caseness thresholds, 18.9% of the potentially morally injurious event (pMIE) endorsers met criteria for moral injury as a clinical syndrome and an additional 21.4% for moral distress (subclinical), with blended shame and trust violation presentations characterizing the majority (53.1%) of clinical cases. Patient Health Questionnaire-9 scores exceeded the clinical threshold for moderate depression (M = 10.96, SD = 6.27). One-way analysis of variance revealed significant sector differences in functional impairment, trust violations, and depression, with shelter workers reporting the highest levels across nearly all measures. The MIOS Shame subscale was more strongly associated with both depression (r = .646) and functional impairment (r = .343) than the Trust Violations subscale, which showed no significant relationship with functional impairment (r = .045, p = .456). Endorsement of the direct participation pathway was the only exposure pathway significantly associated with caseness classification, with 31.8% of direct participation endorsers meeting criteria for moral injury compared to 12.0% of non-endorsers (p < .001). A departure from standard MIOS administration presenting impact items to all participants revealed that a small number of pMIE non-endorsers met caseness thresholds despite actively denying exposure, raising questions about the comprehensiveness of current pathway categories.

Discussion:

These findings identify moral injury as a prevalent and clinically significant occupational experience among animal care workers, with distinct shame-based and trust violation-based mechanisms in predicting functional decline and clinical severity, respectively. Implications for targeted intervention and organizational reform are discussed.

Introduction

Animal care workers experience significant occupational distress, and the field’s understanding of these challenges has been shaped predominantly by constructs of burnout (1, 2), compassion fatigue (3, 4), and secondary traumatic stress (5). While attention to these constructs has meaningfully advanced awareness of worker well-being, inconsistent terminology and persistent conceptual confusion among these constructs continues to impede both research and targeted intervention (6, 7), and a growing body of evidence suggests that these frameworks may be insufficient to capture the full phenomenology of occupational harm in this population (8–10). The construct of moral injury offers a framework for understanding ethical and systemic dimensions of professional suffering that these existing constructs do not address.

Moral injury refers to the lasting psychological, behavioral, social, and spiritual harm resulting from exposure to events that transgress one’s deeply held moral beliefs and expectations (11). While many traumatic events can wound an individual physically and psychologically (12), moral injury draws attention to a distinct mechanism of harm that is rooted not in threats to one’s life but in threats to one’s values (13). A potentially morally injurious event (pMIE) is an event that has the capacity to violate an individual’s moral code and deeply held concepts of right and wrong, including acts of perpetration or omission by the self or others (11). Moral injury is conceptualized as occurring through three pathways—transgression-self, transgression-other, and betrayal—each of which carries distinct phenomenological implications (11, 14, 15) and differential consequences for moral emotions, relational behavior, and prosocial functioning (16). It has been emphasized that moral injury is best understood as a dimensional construct with clinical significance ranging from subclinical moral distress to a fully expressed clinical syndrome, an approach that has now been operationalized through validated caseness thresholds for the Moral Injury Outcomes Scale (MIOS) in military populations (17).

While moral injury was originally conceptualized in military populations (11, 18), research has increasingly recognized its relevance across civilian occupational contexts where workers routinely encounter ethically complex, high-stakes situations (19). This expansion has been most pronounced in healthcare settings, where the moral dimensions of occupational harm gained significant empirical attention during and after COVID-19 (20) and where scholars have argued that moral injury more accurately captures clinician distress than the burnout framework (21). First responders and public safety personnel represent another emerging area of focus (22), as institutional structures and operational demands in these fields regularly expose workers to potential moral harm (13, 23).

The recognition of moral injury has also recently gained broader institutional momentum. In September 2025, the American Psychiatric Association expanded Z code Z65.8 in the DSM-5-TR to include “Moral, Religious, or Spiritual Problem,” formally acknowledging that experiences which “disrupt one’s understanding of right and wrong, or one’s sense of the goodness of oneself, others, or institutions, may warrant clinical attention (24).” While moral injury remains classified as a condition that may be a focus of clinical attention rather than a formal diagnostic category, this recognition represents a significant step toward integrating moral dimensions of suffering into psychiatric and clinical practice.

As moral injury gains clinical and institutional recognition, empirical data are needed to determine its relevance across occupational populations. Moral injury prevalence data have recently become available for military and healthcare populations; Maguen and colleagues (25) reported prevalence rates across combat veterans, healthcare workers, and first responders, and Litz and colleagues (17) established caseness thresholds in a nationally representative veteran sample using the MIOS. However, no study has applied a validated moral injury syndrome measure with clinical caseness thresholds to an animal care population. While preliminary research has examined moral injury in shelter workers using adapted versions of the Moral Injury Events Scale (8), this measure assesses exposure to morally injurious events rather than the clinical syndrome of moral injury, and these studies have been limited to single sectors. The absence of syndrome-level prevalence data grounded in a validated outcome measure with clinical thresholds leaves the field without empirically grounded estimates of moral injury severity, subvariant presentation, or cross-sector variation, relying instead on proxy indicators of moral harm, such as burnout and compassion fatigue scores, which do not capture the moral-evaluative and relational dimensions central to moral injury.

Furthermore, what empirical attention has been directed toward psychological distress in animal care has been concentrated in a narrow range of sectors, leaving the broader landscape of animal care work largely unexamined. Existing literature has given considerable attention to veterinary medicine (26–30) and demonstrates growing attention to shelter worker mental health (8, 31) contributing substantially to awareness of occupational distress in these populations. At the same time, other sectors within animal care have been dramatically overlooked. Animal control workers, despite being classified alongside police officers and firefighters in the highest-risk occupational group for workplace suicide (32) have been virtually absent from the empirical literature as a distinct population, with no published studies examining their psychological outcomes independent of the broader shelter worker category; existing research dedicated to this sector has focused on job realities rather than worker well-being specifically (33). Other underexamined populations include zoo and aquarium workers (34, 35), wildlife carers (36), laboratory animal care workers, pet care professionals such as groomers and trainers, and animal cremation and burial workers, none of whom have been studied with respect to moral injury. No study to date has systematically measured moral injury endorsement rates across the breadth of animal care sectors.

Animal care work shares the structural conditions associated with moral injury in military and healthcare populations: workers across sectors routinely face euthanasia decisions (2, 8), exposure to animal suffering and death (31, 36), resource constraints that force impossible choices in high-stakes situations (10), institutional limitations on ethical practice (37, 38), and challenging public interactions (38) — conditions that map directly onto the transgression-self, transgression-other, and betrayal pathways through which moral injury is theorized to occur (11).

The present study addresses these gaps by providing the first empirical examination of moral injury endorsement rates and phenomenology in a cross-sector sample of animal care workers. Using the MIOS (39) and the Patient Health Questionnaire-9 (PHQ-9), the author assessed morally injurious experience pathways, impact severity, functional impairment, and depression in 291 participants spanning rescue, shelter, animal control, veterinary medicine, volunteer/foster, and other animal care roles. The present study represents one of the first applications of these recently published caseness thresholds to any non-veteran population. Specifically, this study aimed to:

Estimate the frequency of morally injurious experiences across exposure pathways (witnessed, direct participation, and affected by others’ transgressions).

Characterize the severity and functional impact of moral injury in this population. Given the recent publication of norm-referenced caseness thresholds (17), the author further applied these criteria to distinguish moral distress from clinical moral injury and to examine subvariant presentations.

Examine sector differences in moral injury exposure rates, severity, and associated depression.

Investigate the differential relationships between moral injury dimensions (shame vs. trust violations) and psychological outcomes.

Materials and methodsProcedure

This cross-sectional survey study was reviewed for exempt research determination by Pearl IRB and determined to be Exempt according to 45 CFR 46.104(d)(2) on 06/11/2024 (IRB ID 2024-0249). Participants were recruited through convenience and snowball sampling via social media, animal care professional networks, and animal care organizations in the United States. Data were collected between June 2024 and July 2024. Participants provided informed consent electronically prior to beginning the survey. Inclusion criteria required active involvement in animal care work at the time of survey completion. No compensation was provided for participation, though participants had the option to register for a chance to win one of ten $25 Amazon gift cards.

The survey consisted of 106 items and included demographic items (age, gender, race/ethnicity, education, geographic location, years in animal care, weekly hours, species served), care role classification (14 options), an author-constructed 12-item exposure scale (analyzed in a separate publication; 40), the MIOS (comprised of one exposure item, 14 impact items and 8 functional impairment items), the PHQ-9, and additional validated measures analyzed in separate publications. Upon completion of the 106-item survey, participants were presented with an optional Part 2 survey consisting of an additional 99 items. Part 2 (n = 151) included additional validated measures and supplementary items, the results of which are reported in separate publications (38, 40). The present analyses draw exclusively from Part 1 data as a complete stand-alone investigation (N = 291).

Participants

A total of 393 individuals accessed the survey; 390 provided informed consent. Five were excluded for not meeting the inclusion criterion of current involvement in animal care work. Of the remaining 385 respondents, 291 provided sufficient data to be included in the analytic sample. Complete data were available for all 291 participants on the PHQ-9. Ten participants did not complete the MIOS Impact items, yielding n = 281 for MIOS-based analyses, and five additional participants did not complete functional impairment items, yielding n = 286. The remaining 94 were excluded due to incomplete responses on one or more primary measures. Participants were 291 adults who self-identified as currently working or volunteering in animal care (Supplementary Table 1). The sample was predominantly female (64.9%, n = 189), White (81.4%, n = 237), with an age range from 18–80 and a mean age of 36.8 years (SD = 10.12). Participants reported their U.S. state or territory of residence, which was subsequently classified into four geographic regions using U.S. Census Bureau regional definitions. The South was most represented (42.8%, n = 124). The majority held a bachelor’s degree or higher (64.6%, n = 188). Staff members comprised 81.4% (n = 237) of the sample, with 10.3% (n=30) identifying as volunteer/foster only and 8.2% (n=24) in other animal care roles.

Participants indicated all animal care roles they currently held from a list of 14 options: full-time public shelter employee, part-time public shelter employee, full-time private rescue employee, part-time private rescue employee, animal control/investigation, shelter or rescue volunteer, foster, veterinarian, veterinary technician/assistant, other veterinary role, animal trainer/behaviorist, conservation-related, other animal care role with shelter interaction, and other animal care role without shelter interaction. These were consolidated into six primary sector categories for analysis: animal control, shelter (full- and part-time), veterinary medicine (veterinarian, veterinary technician, and other veterinary staff), rescue (full- and part-time), volunteer/foster, and other animal care roles (including training/behavior, conservation, and roles not fitting the preceding categories). For participants endorsing multiple roles (34.7%, n = 101), primary sector assignment was applied using a hierarchy informed by ecological systems theory (41), which conceptualizes human experience as shaped by nested environmental systems. Roles were prioritized by the extent to which they are structurally defined by multiple institutional systems including statutory legal mandates, governmental authority, professional licensure, and organizational formality, with the resulting hierarchy ranking animal control as the most institutionally embedded, followed by shelter, veterinary medicine, rescue, and volunteer/foster. This approach is consistent with the Job Demands-Resources model (42), which identifies organizational context as a moderator of the relationship between job demands and worker outcomes. Participants represented six primary sectors: rescue (29.9%, n = 87), shelter (22.7%, n= 66), animal control (18.2%, n = 53), veterinary medicine (10.7%, n = 31), volunteer/foster (10.3%, n = 30), and other animal care roles (8.2%, n = 24). Volunteers and fosters were included because they represent a substantial proportion of the animal care workforce, are exposed to many of the same occupational conditions and stressors as paid staff (36), and their inclusion enables examination of whether employment status moderates moral injury outcomes.

A majority had worked in animal care for 3 or more years (89.3%, n = 259), and the majority of participants reported substantial weekly engagement, with 62.4% (n = 181) working or volunteering 40 or more hours per week in animal care roles and 80.0% (n = 232) reporting 30 or more hours per week. Overall, 30.7% (n = 89) reported no hours in paid or volunteer work outside of animal care, suggesting that for many participants, animal care represented their primary or sole occupational role. Participants primarily worked with dogs and cats (81.1%, n = 236), though the sample also included workers serving wildlife (16.2%, n = 47), farm animals (16.2%, n = 47), exotic animals (10.3%, n = 30), marine animals (6.5%, n = 19), and research/laboratory animals (1.7%, n = 5), reflecting the diversity of the animal care workforce.

MeasuresMoral Injury Outcome Scale

The MIOS (39) was selected based on an extensive review of moral injury measurement approaches conducted during prior research on moral injury in military populations (16). Existing measures were evaluated on their capacity to separately assess exposure and syndrome impact, their applicability beyond military contexts, and their ability to capture dimensional variation in moral injury presentations. The MIOS was identified as the most suitable measure for cross-sector occupational research because: (a) it independently assesses both pMIE exposure pathways and moral injury impact as a syndrome, enabling prevalence estimation at both levels; (b) it was developed and validated across multinational civilian and military samples through the Moral Injury Outcome Scale Consortium (39, 43) establishing its applicability beyond military contexts; and (c) its two-subscale structure (Shame and Trust Violations) permits examination of differential mechanisms of harm. Following the 2024 data collection in this study, newly published norm-referenced caseness thresholds enabled improved and clinically meaningful severity classification not available for other measures (17).

The MIOS (39) is a self-report measure of morally injurious experiences and their psychological and functional impact. The exposure component consists of a single item presenting three pathway options from which participants could select all that applied: “I did something or failed to do something that went against my moral code or values” (hereafter DID), “I saw or witnessed something that went against my moral code or values” (hereafter SAW), and “I was directly affected by someone doing something or failing to do something that went against my moral code or values” (hereafter AFFECTED), along with a “None of the above” option. The Impact scale comprises 14 items rated on a 0 (strongly disagree) to 4 (strongly agree) scale, yielding a total score (range: 0–56) and two subscale scores: Shame (7 items; range: 0–28) and Trust Violations (7 items; range: 0–28). The Functional Impairment scale comprises 8 items rated on a 0 (not at all) to 6 (extremely) scale assessing impairment across life domains (work, relationships, spirituality, daily activities, education). In the present sample, internal consistency was excellent for the Impact Total (α = .906), Shame subscale (α = .883), Trust Violations subscale (α = .836), and Functional Impairment scale (α = .936).

In the standard MIOS administration protocol, participants who do not endorse any exposure pathway are not administered the impact or functional impairment items (39). In the present study, all participants were presented with the impact and functional impairment items for optional completion regardless of pathway endorsement. This departure from standard protocol was a deliberate design choice for four reasons: (a) as the first broad application of the MIOS to an animal care population, there was no prior basis for assuming the three pathway categories would comprehensively capture morally injurious experiences in this workforce; (b) presenting impact items to all participants enabled exploratory examination of potential measurement gaps in a population not previously studied; (c) the optional completion format preserved participants’ autonomy to skip items they deemed irrelevant while allowing those with clinical-level symptoms to report them regardless of pathway endorsement; and (d) given the theoretical possibility that moral distress may operate below full conscious awareness in chronically exposed populations, administering impact items regardless of pathway endorsement provided an empirical test of the author’s hypothesis that workers in morally saturated environments may internalize the effects of ongoing ethical violations without identifying discrete precipitating events.

Patient Health Questionnaire-9

The PHQ-9 (44) is a 9-item self-report measure of depressive symptom severity over the past two weeks, rated on a 0 (not at all) to 3 (nearly every day) scale. Total scores range from 0 to 27, with established clinical cutoffs of 5 (mild), 10 (moderate), 15 (moderately severe), and 20 (severe). The PHQ-9 demonstrated good internal consistency in the present sample (α = .887). The PHQ-9 was selected as the convergent validity comparator because depression has been consistently associated with moral injury across populations (13, 19) and represents the most commonly documented clinical correlate.

Data analysisScoring and variable construction

MIOS Impact Total scores were computed as the sum of 14 impact items (range: 0–56). Shame and Trust Violations subscale scores were computed as the sum of their respective 7-item sets (range: 0–28 each). The MIOS Functional Impairment scale includes a not-applicable option for non-relevant life domains; functional impairment scores were calculated as mean scores across applicable items, consistent with B-IPF scoring procedures (45). PHQ-9 scores were computed as the sum of 9 items (range: 0–27). One participant did not respond to the MIOS exposure pathway item and was conservatively coded as not endorsing any pathway, as this participant completed all other survey items, suggesting engaged responding, and treating non-response as non-endorsement provides a conservative estimate. Sensitivity analyses excluding this participant did not alter any reported findings.

Recent caseness classification (17) was published subsequent to data collection and is applied here as the most current empirically supported framework for MIOS interpretation.1 The present analyses apply the norm reference T-score-derived thresholds for distinguishing among no clinically significant moral distress or injury, moral distress (subclinical, T = 60–64; raw scores 26–30), and moral injury (clinical syndrome, T ≥ 65; raw scores ≥ 31) (17). These thresholds were validated in a nationally representative veteran sample (N = 3,002) through concurrent comparison with established measures of PTSD, depression, functioning, and suicidality, demonstrating clear progressive differentiation across classification groups. Subvariant classification was determined by whether participants exceeded 1 SD above the sample mean on the Shame subscale, the Trust Violations subscale, both, or neither. Population-specific norms for animal care workers have not yet been established; the present study applies the veteran-derived raw score thresholds as the best available empirically supported framework for MIOS caseness classification.

Statistical analyses

All analyses were conducted in IBM SPSS Statistics (Version 29). Descriptive statistics were computed for all study variables, including means, standard deviations, skewness, and kurtosis. Moral injury exposure rates were calculated as the proportion of participants endorsing each MIOS exposure pathway and combinations thereof. Internal consistency was assessed using Cronbach’s alpha. One-way analyses of variance (ANOVA) with Tukey HSD post-hoc comparisons examined sector differences on MIOS scales and PHQ-9 scores, with eta-squared (η²) as the effect size measure. Levene’s test assessed homogeneity of variance; Welch’s robust test was applied where Levene’s test indicated unequal variances across groups. Normality was assessed within each sector group; skewness values ranged from -.657 to.658 and kurtosis values ranged from -1.618 to 1.311 across all sector × outcome variable combinations, all within acceptable ranges for parametric tests. Although some Shapiro-Wilk tests reached significance in larger subgroups, ANOVA is robust to moderate departures from normality with the group sizes in this study (n = 21–85). Bivariate Pearson correlations examined relationships among MIOS subscales, functional impairment, and depression. Chi-square analyses examined the association between each pMIE pathway and caseness classification independently; for each analysis, participants were classified as endorsing or not endorsing the specific pathway (e.g., DID endorsers vs. non-DID endorsers), creating independent groups within each test. Each chi-square test evaluated the null hypothesis that caseness classification was independent of pathway endorsement status, that is, the proportion of participants meeting each caseness threshold would not differ between those who endorsed a given pathway and those who did not. Because participants could endorse multiple pathways, these pathway-specific analyses are not independent of one another across tests. A separate chi-square examined the association between subvariant classification and caseness. Cramér’s V was used as the effect size measure for all chi-square analyses. Statistical significance was set at p <.05 for all tests.

ResultsDescriptive statistics and scale properties

All MIOS and PHQ-9 distributions approximated normality, with skewness values ranging from.045 to.257 and kurtosis values ranging from –1.172 to –.016, supporting the use of parametric tests. Descriptive statistics for all study scales are presented in Table 1. The mean MIOS Impact Total score was 21.49 (SD = 10.45) on a 0–56 scale, representing 38.4% of the maximum score. The Trust Violations subscale mean (M = 11.88, SD = 5.51) exceeded the Shame subscale mean (M = 9.62, SD = 6.11) on the same 0–28 range, indicating that trust violation was the more commonly endorsed dimension of moral injury impact in this sample. The mean PHQ-9 score of 10.96 (SD = 6.27) exceeded the established clinical cutoff of 10 for moderate depression (44) indicating that the animal care workforce represented in this sample is experiencing clinically meaningful depressive symptomatology.

VariableNMSDRangeSkewnessKurtosisαMIOS Total Score28121.4910.450-56.18-.02.906MIOS Shame2819.626.110-28.26-.57.883MIOS Trust Violations28111.885.510-28.06-.15.836MIOS Functional Impairment2862.421.770-6.13-1.17.936PHQ-9 Depression29010.966.270-27.05-.56.887

Descriptive statistics and internal consistency for study scales (N = 291).

MIOS Functional Impairment scores reflect the item mean across 8 domains (0–6 scale). All other scores reflect scale totals.

Internal consistency was excellent across all MIOS scales (α range: .836–.906; see Table 1). These values are comparable to or exceed those reported by Litz et al. (39) in the multinational validation sample (α = .90 total) and by Litz et al. (17) in a nationally representative veteran sample (α = .89 total, .88 shame, .78 trust violation), supporting the reliability of the MIOS in a non-military occupational population.

Aim 1: exposure frequency to morally injurious experiences

The vast majority of participants (83.5%, n = 243) endorsed at least one morally injurious experience pathway. Witnessing morally violative events was the most frequently endorsed pathway (63.9%, n = 186), followed by being affected by others’ transgressions (38.5%, n = 112) and direct participation (29.2%, n = 85). Of the total sample, 49.5% (n = 144) endorsed a single pathway, 19.9% (n = 58) endorsed two pathways, and 14.1% (n = 41) endorsed all three. The most common single-pathway endorsement was witnessing only (31.6%, n = 92). The most common multi-pathway combination was endorsement of all three pathways simultaneously (14.1%, n = 41), followed by witnessing combined with being affected by others’ transgressions (12.7%, n = 37). Exposure rates for all pathway combinations are presented in Table 2.

Pathwayn%Any pathway endorsed24383.5Witnessed (SAW)18663.9Affected by others’ transgressions (AFFECTED)11238.5Direct participation (DID)8529.2No pathway endorsed4816.5CombinationSingle pathway SAW only9231.6 AFFECTED only2910.0 DID only237.9 Single pathway subtotal14449.5Two pathways SAW + AFFECTED3712.7 DID + SAW165.5 DID + AFFECTED51.7 Two pathway subtotal5819.9Three pathways DID + SAW + AFFECTED4114.1

Moral injury pathway endorsement and combinations (N = 291).

Aim 2: MIOS severity, caseness, and subvariant classification

Among participants with valid MIOS scores (n = 281; 10 participants did not complete the impact items), the total score distribution was approximately normal (skewness = .18, kurtosis = −.02). Applying the 2025 (17) T-score-derived caseness thresholds to the full analytic sample, 61.6% (n = 173) showed no clinically significant moral distress or injury, 21.0% (n = 59) met criteria for moral distress (subclinical), and 17.4% (n = 49) met criteria for moral injury as a clinical syndrome. Among pMIE endorsers specifically (n = 243), 18.9% (n = 46) met criteria for moral injury and 21.4% (n = 52) for moral distress, with 59.7% (n = 145) falling below clinical thresholds.

Chi-square analyses examined the association between pMIE pathway endorsement and caseness classification among pMIE endorsers (n = 243). Endorsement of the agentic pathway (DID: “I did something or failed to do something”) was significantly associated with caseness, χ²(2) = 14.09, p <.001, Cramér’s V = .241. Among participants who endorsed the DID pathway (n = 85), 31.8% met criteria for moral injury, compared to 12.0% of those who did not endorse this pathway (n = 158). Neither the witnessing pathway (SAW), χ²(2) = 4.69, p = .096, Cramér’s V = .139, nor the directly affected pathway (AFFECTED), χ²(2) = 0.47, p = .792, Cramér’s V = .044, was significantly associated with caseness. The number of pathways endorsed (1–3) was not significantly associated with caseness, χ²(4) = 2.34, p = .673, Cramér’s V = .069, though the proportion meeting moral injury criteria increased descriptively from 16.0% among single-pathway endorsers (n = 144) to 22.4% for two pathways (n = 58) to 24.4% for three pathways (n = 41).

To examine the mechanism through which agentic pathway endorsement was associated with caseness, independent samples t-tests compared MIOS subscale scores between DID endorsers and non-endorsers from among the pMIE endorsers dataset (n = 243). DID endorsers scored significantly higher on both the Shame subscale (M = 12.22, SD = 5.82 vs. M = 9.15, SD = 5.77), t(241) = -3.95, p <.001, d = .53, and the Trust Violations subscale (M = 13.53, SD = 5.11 vs. M = 11.65, SD = 5.00), t(241) = -2.78, p = .006, d = .37. A chi-square analysis examining the association between DID endorsement and subvariant classification was significant, χ²(3) = 12.81, p = .005, Cramér’s V = .230. DID endorsers were three times more likely than non-endorsers to present with both subscales elevated (17.6% vs. 5.7%) and less likely to fall in the neither-elevated category (56.5% vs. 75.9%).

Among moral injury cases (n = 49), the majority presented with blended subvariant symptoms involving both shame-related and trust violation-related elevations (53.1%, n = 26), followed by shame-related only (26.5%, n = 13) and trust violation-related only (20.4%, n = 10). Among moral distress cases (n = 59), 64.4% (n = 38) did not meet the 1 SD threshold on either subscale, 23.7% (n = 14) showed shame-related elevations only, and 11.9% (n = 7) showed trust violation-related elevations only; no moral distress cases presented with both subvariants elevated.

The association between subvariant classification and caseness was highly significant, χ²(3) = 64.191, p <.001, Cramér’s V = .771, a large effect. All participants classified as having both shame and trust violation elevations met criteria for moral injury (n = 26, 100%), while all participants classified as having neither subscale elevated fell below clinical thresholds for moral injury, in the moral distress (subclinical) range (n = 38, 100%). Among single-subvariant presentations, shame-only cases were roughly evenly split between moral distress (51.9%, n = 14) and moral injury (48.1%, n = 13), while trust violation-only cases showed a slight clinical-leaning distribution (58.8% moral injury, n = 10; 41.2% moral distress, n = 7). The distribution of subvariant classifications across caseness categories are presented in Table 3.

SubvariantMoral distress n(%)Moral injury n(%)Neither elevated38(100.0)0(0.0)Shame related only14(51.9)13(48.1)Trust Violation Only7(41.2)10(58.8)Both elevated0(0.0)26(100.0)Total59(54.6)49(45.4)

MIOS subvariant classification by caseness among participants meeting distress or injury thresholds (n = 108).

χ²(3) = 64.191, p <.001, Cramér’s V = .771. Subvariant classification based on subscale scores ≥ 1 SD above the pMIE endorser mean (Shame ≥ 16; Trust Violations ≥ 17). Moral Distress = MIOS Impact Total 26–30; Moral Injury = MIOS Impact Total ≥ 31.

Aim 3: sector differences in moral injury and depression

One-way ANOVAs revealed statistically significant sector differences on three of five outcome variables (Table 4). Sector accounted for the largest proportion of variance in functional impairment, F(5, 280) = 7.40, p <.001, η² = .117, a medium effect. Significant sector differences also emerged for MIOS Trust Violations, F(5, 275) = 2.96, p = .013, η² = .051 and PHQ-9 Depression, F(5, 284) = 3.31, p = .006, η² = .055. A fourth outcome variable, MIOS Impact Total, F(5, 275) = 2.30, p = .045, η² = .040 revealed an ambiguous effect that should be interpreted cautiously, as it showed statistically significant on one-way ANOVA but did not reach significance under Welch’s robust test (p = .060). Sector differences in the Shame subscale were not significant.

VariableAnimal control
M (SD)
(n = 53)Shelter M (SD) (n = 66)Vet med
M (SD)
(n = 31)Rescue
M (SD)
(n = 87)Vol/foster M (SD) (n = 30)Other
M (SD)
(n = 24)Fpη²MIOS Total Impact21.02 (10.26)24.98 (10.99)20.00 (11.34)20.18 (9.98)18.96 (8.42)22.71 (10.58)2.30.045.040MIOS Shame8.90 (6.02)11.18 (6.47)9.50 (6.56)9.41 (5.80)7.79 (4.80)10.00 (6.82)1.55.173.027MIOS Trust Violations12.12 (5.39)13.80 (5.44)10.50 (5.86)10.76 (5.24)11.18 (5.32)12.71 (5.59)2.96.013.051MIOS Functional Impairment2.50 (1.71)2.47 (1.43)2.08 (1.57)2.99 (1.98)0.84 (1.09)2.31 (1.79)7.40<.001.117PHQ-9 Depression10.13 (6.53)12.98 (6.47)9.03 (6.89)11.67 (5.35)9.38 (6.89)9.04 (5.08)3.31.006.055

Scale means by primary sector with ANOVA results.

Sector n’s reflect primary sector classification. Analytic n’s vary slightly across measures due to missing data (total analytic n: MIOS scales = 281, Functional Impairment = 286, PHQ-9 = 290). Functional Impairment reflects the item mean (0–6 scale). Significant Tukey HSD comparisons: VF < AC, SH, RE, and OT on Functional Impairment (all p <.05); SH > RE on Trust Violations (p = .010); SH > VM on Depression (p = .040). Levene’s test was significant for Functional Impairment (p <.001); Welch’s F(5, 96.09) = 12.30, p <.001 confirmed the result. Impact Total reached significance under standard ANOVA but not under Welch’s test (p = .060).

Tukey HSD post-hoc comparisons identified three specific pairwise differences. First, volunteer/foster workers reported significantly lower functional impairment than animal control, shelter, rescue, and other sector workers (all p <.05), emerging as a distinct homogeneous subset. Second, shelter workers reported significantly higher trust violations than rescue workers (p = .010). Third, shelter workers reported significantly higher depression than veterinary medicine workers (p = .040). Across all measures, shelter workers reported the highest mean scores while vo