Precision Assessment of Real-World Associations Between Stress and Sleep Duration Using Actigraphy Data Collected Continuously for an Academic Year: Individual-Level Modeling Study.

BACKGROUND: Heightened stress and insufficient sleep are common in the transition to college, often co-occur, and have both been linked to negative health outcomes. A challenge concerns disentangling whether perceived stress precedes or succeeds changes in sleep. These day-to-day associations may vary across individuals, but short study periods and group-level analyses in prior research may have obscured person-specific phenotypes. OBJECTIVE: This study aims to obtain stable estimates of lead-lag associations between perceived stress and objective sleep duration in the individual, unbiased by the group, by developing an individual-level linear model that can leverage intensive longitudinal data while remaining parsimonious. METHODS: In total, 55 college students (n=6, 11% second-year students and n=49, 89% first-year students) volunteered to provide daily self-reports of perceived stress via a smartphone app and wore an actigraphy wristband for the estimation of daily sleep duration continuously throughout the academic year (median usable daily observations per participant: 178, IQR 65.5). The individual-level linear model, developed in a Bayesian framework, included the predictor and outcome of interest and a covariate for the day of the week to account for weekly patterns. We validated the model on the cohort of second-year students (n=6, used as a pilot sample) by applying it to variables expected to correlate positively within individuals: objective sleep duration and self-reported sleep quality. The model was then applied to the fully independent target sample of first-year students (n=49) for the examination of bidirectional associations between daily stress levels and sleep duration. RESULTS: Proof-of-concept analyses captured expected associations between objective sleep duration and subjective sleep quality in every pilot participant. Target analyses revealed negative associations between sleep duration and perceived stress in most of the participants (45/49, 92%), but their temporal association varied. Of the 49 participants, 19 (39%) showed a significant association (probability of direction>0.975): 8 (16%) showed elevated stress in the day associated with shorter sleep later that night, 5 (10%) showed shorter sleep associated with elevated stress the next day, and 6 (12%) showed both directions of association. Of note, when analyzed using a group-based multilevel model, individual estimates were systematically attenuated, and some even reversed sign. CONCLUSIONS: The dynamic interplay of stress and sleep in daily life is likely person specific. Paired with intensive longitudinal data, our individual-level linear model provides a precision framework for the estimation of stable real-world behavioral and psychological dynamics and may support the personalized prioritization of intervention targets for health and well-being.

Machine Learning Based Linking of Patient Reported Outcome Measures to WHO International Classification of Functioning, Disability, and Health Activity/Participation Categories.

BACKGROUND: In the primary and secondary medical health sector, patient reported outcome measures (PROMs) are widely used to assess a patient's disease-related functional health state. However, the World Health Organization (WHO), in its recently adopted resolution on "strengthening rehabilitation in all health systems", encourages that all health sectors, not only the rehabilitation sector, classify a patient's functioning and health state according to the International Classification of Functioning, Disability and Health (ICF). AIM: This research sought to optimize machine learning (ML) methods that fully and automatically link information collected from PROMs in persons with unspecific chronic low back pain (cLBP) to limitations in activities and restrictions in participation that are listed in the WHO core set categories for LBP. The study also aimed to identify the minimal set of PROMs necessary for linking without compromising performance. METHODS: A total of 806 patients with cLBP completed a comprehensive set of validated PROMs and were interviewed by clinical psychologists who assessed patients' performance in activity limitations and restrictions in participation according to the ICF brief core set for low back pain (LBP). The information collected was then utilized to further develop random forest (RF) methods that classified the presence or absence of a problem within each of the activity participation ICF categories of the ICF core set for LBP. Further analyses identified those PROM items relevant to the linking process and validated the respective linking performance that utilized a minimal subset of items. RESULTS: Compared to a recently developed ML linking method, receiver operating characteristic curve (ROC-AUC) values for the novel RF methods showed overall improved performance, with AUC values ranging from 0.73 for the ICF category d850 to 0.81 for the ICF category d540. Variable importance measurements revealed that minimal subsets of either 24 or 15 important PROM variables (out of 80 items included in full set of PROMs) would show similar linking performance. CONCLUSIONS: Findings suggest that our optimized ML based methods more accurately predict the presence or absence of limitations and restrictions listed in ICF core categories for cLBP. In addition, this accurate performance would not suffer if the list of PROM items was reduced to a minimum of 15 out of 80 items assessed.

Race and ethnicity moderate the associations between lifetime psilocybin use and crime arrests.

Introduction: Psilocybin use has been linked to lowered odds of crime-related outcomes across a host of observational studies. No studies have investigated how these associations may differ among those of different races and ethnicities. Methods: Using a nationally-representative sample of 734,061 adults from the National Survey on Drug Use and Health (2002-2020), we investigated whether race and ethnicity moderate the associations between lifetime psilocybin use and four measures of crime arrests (property crime, assault, serious violence, and miscellaneous crimes). Results: First, we replicated prior findings and demonstrated that psilocybin confers lowered odds of crime arrests for all four outcomes in question. Second, we demonstrated that race and ethnicity moderate the associations between lifetime psilocybin use and crime arrests for three of our four outcomes. Third, we examined the associations between psilocybin and crime arrests across different races and ethnicities (White, Black, Indigenous, Asian, Multiracial, and Hispanic participants). Psilocybin conferred lowered odds of at least one crime arrest outcome for all racial and ethnic groups except for Black and Hispanic participants. Discussion: Future investigations should take an intersectional approach to studying the interrelationship of sociodemographic factors, psychedelic use, and crime, examine the structural factors (i.e., systemic racism) that may underlie these results, and investigate whether psychedelics can alleviate mental health disorders that contribute to cycles of recriminalization for communities of color.

The Back Muscle Surface Electromyography-Based Fatigue Index: A Digital Biomarker of Human Neuromuscular Aging?

As part of our quest for digital biomarkers of neuromuscular aging, and encouraged by recent findings in healthy volunteers, this study investigated if the instantaneous median frequency (IMDF) derived from back muscle surface electromyographic (SEMG) data monitored during cyclic back extensions could reliably differentiate between younger and older individuals with cLBP. A total of 243 persons with cLBP participated in three experimental sessions: at baseline, one to two days after the first session, and then again approximately six weeks later. During each session, the study participants performed a series of three isometric maximal voluntary contractions (MVC) of back extensors using a dynamometer. These were followed by an isometric back extension at 80% MVC, and-after a break-25 slow cyclic back extensions at 50% MVC. SEMG data were recorded bilaterally at L5 (multifidus), L2 (longissimus dorsi), and L1 (iliocostalis lumborum). Linear mixed-effects models found the IMDF-SEMG time-course changes more rapidly in younger than in older individuals, and more prominently in male participants. The absolute and relative reliabilities of the SEMG time-frequency representations were well compared between older and younger participants. The results indicated an overall good relative reliability, but variable absolute reliability levels. IMDF-SEMG estimates derived from cyclic back extensions proved to be successful in reliably detecting differences in back muscle function in younger vs. older persons with cLBP. These findings encourage further research, with a focus on assessing whether an IMDF-SEMG-based index could be utilized as a tool to achieve the preclinical detection of back muscle aging, and possibly predict the development of back muscle sarcopenia.

Evaluation of a Model to Target High-risk Psychiatric Inpatients for an Intensive Postdischarge Suicide Prevention Intervention.

Importance: The months after psychiatric hospital discharge are a time of high risk for suicide. Intensive postdischarge case management, although potentially effective in suicide prevention, is likely to be cost-effective only if targeted at high-risk patients. A previously developed machine learning (ML) model showed that postdischarge suicides can be predicted from electronic health records and geospatial data, but it is unknown if prediction could be improved by adding additional information. Objective: To determine whether model prediction could be improved by adding information extracted from clinical notes and public records. Design, Setting, and Participants: Models were trained to predict suicides in the 12 months after Veterans Health Administration (VHA) short-term (less than 365 days) psychiatric hospitalizations between the beginning of 2010 and September 1, 2012 (299 050 hospitalizations, with 916 hospitalizations followed within 12 months by suicides) and tested in the hospitalizations from September 2, 2012, to December 31, 2013 (149 738 hospitalizations, with 393 hospitalizations followed within 12 months by suicides). Validation focused on net benefit across a range of plausible decision thresholds. Predictor importance was assessed with Shapley additive explanations (SHAP) values. Data were analyzed from January to August 2022. Main Outcomes and Measures: Suicides were defined by the National Death Index. Base model predictors included VHA electronic health records and patient residential data. The expanded predictors came from natural language processing (NLP) of clinical notes and a social determinants of health (SDOH) public records database. Results: The model included 448 788 unique hospitalizations. Net benefit over risk horizons between 3 and 12 months was generally highest for the model that included both NLP and SDOH predictors (area under the receiver operating characteristic curve range, 0.747-0.780; area under the precision recall curve relative to the suicide rate range, 3.87-5.75). NLP and SDOH predictors also had the highest predictor class-level SHAP values (proportional SHAP = 64.0% and 49.3%, respectively), although the single highest positive variable-level SHAP value was for a count of medications classified by the US Food and Drug Administration as increasing suicide risk prescribed the year before hospitalization (proportional SHAP = 15.0%). Conclusions and Relevance: In this study, clinical notes and public records were found to improve ML model prediction of suicide after psychiatric hospitalization. The model had positive net benefit over 3-month to 12-month risk horizons for plausible decision thresholds. Although caution is needed in inferring causality based on predictor importance, several key predictors have potential intervention implications that should be investigated in future studies.

Incorporating macro-social contexts into emotion research: Longitudinal associations between structural stigma and emotion processes among gay and bisexual men.

Research into correlates and predictors of emotion regulation has focused almost exclusively on individual differences and the immediate situation. Here, we consider whether features of macro-social contexts may also shape emotion regulation. To test this hypothesis, we conducted a longitudinal study of 502 gay and bisexual men living in 269 U.S. counties that varied in the level of stigma surrounding sexual minorities. We find that gay and bisexual men living in higher- (vs. lower-) stigma counties consistently reported more suppression, which consequently explained longitudinal increases (vs. decreases) in their lack of emotional clarity over 24 months. Results were robust to demographic characteristics, stigma at the interpersonal level (i.e., sexual orientation-related discrimination), and another form of social inequality (i.e., county-level income inequality). These findings suggest that broadening the lens of emotion regulation research to include characteristics of the macro-social environment may yield new insights into determinants of emotion regulation. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Physical Effort Exertion for Peer Feedback Reveals Evolving Social Motivations From Adolescence to Young Adulthood.

Peer relationships and social belonging are particularly important during adolescence. Using a willingness-to-work paradigm to quantify incentive motivation, we examined whether evaluative information holds unique value for adolescents. Participants (N = 102; 12-23 years old) rated peers, predicted how peers rated them, and exerted physical effort to view each peer's rating. We measured grip force, speed, and opt-out behavior to examine the motivational value of peer feedback, relative to money in a control condition, and to assess how peer desirability and participants' expectations modulated motivated effort across age. Overall, when compared with adolescents, adults were relatively less motivated for feedback than money. Whereas adults exerted less force and speed for feedback when expecting rejection, adolescents exerted greater force and speed when expecting to be more strongly liked or disliked. These findings suggest that the transition into adulthood is accompanied by a self-protective focus, whereas adolescents are motivated to consume highly informative feedback, even if negative.

Reproducibility of the 6-minute walk test in lung transplant recipients.

PURPOSE: There is reason to believe that the favorable measurement properties of the 6­minute walk test (6MWT) reported for retest reliability and its capability to detect a true change in healthy individuals or persons with chronic respiratory disease may not apply to lung transplant recipients (LuTXr). We therefore investigated retest reliability of the 6MWT and, in addition, made an attempt to explore whether the 6MWT was sensitive enough to detect important changes that occur with postacute rehabilitation in LuTXr after first time LuTX. METHODS: Immediately before postacute rehabilitation, 50 LuTXr completed 6MWT testing twice, separated by 1-2 workdays (retest reliability), and were reassessed after completion of rehabilitation 2 months later (sensitivity to changes). Body function measures and health-related quality of life (HRQoL) assessments were collected at baseline. RESULTS: Baseline retest 6­minute walk distance (6MWD) and the age-related predicted walking distance (6MWD%pred) scores significantly increased before postacute rehabilitation. The intraclass coefficient of correlation ICC of the 6MWD was 0.93 (95% confidence interval, CI: 0.88-0.96) and its smallest real difference (SRD) 79 m (95% CI: 52;107). Receiver operating curve analyses revealed the rehabilitation associated changes in 6MWD/6MWD%pred to exceed the SRD/SRD% values in a highly accurate way. CONCLUSION: The 6MWT overall represents a reliable functional performance tool in LuTXr that is sensitive to detect changes in physical performance as a result of medical postacute rehabilitation.

Shifting qualities of negative affective experience through adolescence: Age-related change and associations with functional outcomes.

Research shows negative affect increases in healthy adolescents, and this normative change is paralleled by increasing risk for the onset of psychopathology. However, research is limited in characterizing qualitative differences in the type of negative affect experienced beyond the positive-negative valence dimension. In the current study, we establish the relationship between different forms of negative affect and functioning outcomes (i.e., different facets of social functioning and life satisfaction), and examine whether these forms of negative affect are differentially prevalent across late childhood and adolescence. Seven-hundred and 70 participants aged 8-17 years completed self-report measures that assessed a wide range of negative affective experiences. A factor analysis on the negative affect items revealed a four-factor solution that characterized the dimensions of affective experience, with factors reflecting general anxiety, anger, evaluative anxiety, and sadness. Generalized additive model approaches revealed general anxiety increased nonlinearly with age and was associated with decreased reports of emotional support, a facet of social functioning. Anger was associated with increased perceived hostility, perceived rejection, and decreased life satisfaction, and remained stable across the age range. Evaluative anxiety was associated with greater loneliness and increased linearly with increasing age. Sadness was associated with all outcome measures and showed nonlinear changes with age, with notable increases in midadolescence. These results show that subsuming these subtypes of negative affect under a singular concept may obscure meaningful relationships between affect, age, and functioning. Exploring diverse forms of negative affect may help refine theories of emotional development and ultimately inform windows of risk for psychopathology. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Using Support Vector Machines for Facet Partitioning in Multidimensional Scaling.

In this article we focus on interpreting multidimensional scaling (MDS) configurations using facet theory. The facet theory approach is attempting to partition a representational space, facet by facet, into regions with certain simplifying constraints on the regions' boundaries (e.g., concentric circular sub-spaces). A long-standing problem has been the lack of computational methods for optimal facet-based partitioning. We propose using support vector machines (SVM) to perform this task. SVM is highly attractive for this purpose as they allow for linear as well as nonlinear classification boundaries in any dimensionality. Using various classical examples from the facet theory literature we elaborate on the combined use of MDS and SVM for facet-based partitioning. Different types of MDS are discussed, and options for SVM kernel specification, tuning, and performance evaluation are illustrated.

Do the WHO-ICF personal factors "age" and "sex" impact limited activity and restricted participation category profiles differently between younger and older women and men in multimodal chronic back pain rehabilitation?

PURPOSE: To investigate if the International Classification of Functioning and Health (ICF) context factors "age" and "sex" would impact the disablement and respective improvement with rehabilitation defined with the ICF core set for chronic low back pain (cLBP). Furthermore, associations between limitations/restrictions and measures of body function or quality of life were of interest. MATERIALS AND METHODS: One thousand five hundred and twelve employed cLBP patients who completed 6 months of outpatient rehabilitation and for whom complete assessments were available before and after rehabilitation. Rehabilitation comprised of progressive resistance training, psychological counseling, and educational sessions. Main outcome measures were the ICF-activity/participation core categories automatically predicted from random forests and utilizing information from the Roland Morris Disability Questionnaire and Pain Disability Index. RESULTS: Generalized linear-mixed models revealed that upon completion of rehabilitation the presence of a limitation within the ICF activity "walking" significantly decreased with significant between-group differences. The category "doing housework" demonstrated gender-specific differences, and both gender- and age-specific differences were observed for work-related participation categories. There were no meaningful associations between ICF limitation/restriction categories and body function measures (point-biserial/Spearman's correlations). CONCLUSIONS: The personal factors "age" and "sex" impact some ICF limitation/restriction categories in cLBP; appropriately addressing these personal features could further improve phase III rehabilitation outcome.Implications for rehabilitationConsistent with calls to explore the age and sex/gender influence on health and disease, little is known how these factors affect the disablement of individuals with chronic back pain.The factors "age" and "sex" drive differences in some categories within the ICF activity/restriction categories.If age- and gender-specific features in activities and participation are not appropriately addressed through interventions, rehabilitation outcome may remain suboptimal in cLBP.

Perceived psychosocial stressors and coping resources in chronic low back pain patients as classified by the avoidance-endurance model.

Objectives: The Avoidance-Endurance Model distinguishes between subgroups of low back pain (LBP) patients with three maladaptive styles of coping with pain: fear-avoidance (FAR), distress-endurance (DER), eustress-endurance (EER), and one adaptive coping style (AR). This study aimed to compare the quantity of patients' perceived psychosocial stressors and coping resources across these subgroups. Materials and methods: This cross-sectional study was conducted at an outpatient rehabilitation center for patients with chronic musculoskeletal pain. One hundred and thirty-seven patients (69 women/68 men) with chronic LBP were assessed using the following: a demographic checklist, the visual analogue scale, Avoidance-Endurance Questionnaire, Roland-Morris Disability Questionnaire, Pain Disability Index, and 36-Item Short Form. Subsequently, patients participated in semi-structured interviews led by clinical psychologists, which were intended to identify their perception of stressors and coping resources. The quantity of psychosocial stressors and coping resources were analyzed using deductive and inductive content analyses and then compared between subgroups using chi-square-tests. Results: FARs experienced significantly higher levels of "mental suffering" (p = <0.001) and "other workplace problems" compared to ARs and EERs (p = <0.001). DERs reported significantly higher levels of "mental suffering" (p = <0.001), "job stress" (p = 0.022), and "familial losses" (p = 0.029) compared to ARs, whereas the AR group demonstrated significantly more "coping resources" (p = 0.001) compared to FARs. Conclusion: AEM-subgroups differed in the quantity of perceived psychosocial stressors and coping resources with AR, who demonstrated a lower risk for pain chronicity and reported the highest quantity of resources. The variability across subgroups may imply differences in patients needs regarding therapeutic interventions and suggests that a resource-centered approach to cope with stress and pain may be beneficial.

Graded Variation in T1w/T2w Ratio during Adolescence: Measurement, Caveats, and Implications for Development of Cortical Myelin.

Adolescence is characterized by the maturation of cortical microstructure and connectivity supporting complex cognition and behavior. Axonal myelination influences brain connectivity during development by enhancing neural signaling speed and inhibiting plasticity. However, the maturational timing of cortical myelination during human adolescence remains poorly understood. Here, we take advantage of recent advances in high-resolution cortical T1w/T2w mapping methods, including principled correction of B1+ transmit field effects, using data from the Human Connectome Project in Development (HCP-D; N = 628, ages 8-21). We characterize microstructural changes relevant to myelination by estimating age-related differences in T1w/T2w throughout the cerebral neocortex from childhood to early adulthood. We apply Bayesian spline models and clustering analysis to demonstrate graded variation in age-dependent cortical T1w/T2w differences that are correlated with the sensorimotor-association (S-A) axis of cortical organization reported by others. In sensorimotor areas, T1w/T2w ratio measures start at high levels at early ages, increase at a fast pace, and decelerate at later ages (18-21). In intermediate multimodal areas along the S-A axis, T1w/T2w starts at intermediate levels and increases linearly at an intermediate pace. In transmodal/paralimbic association areas, T1w/T2w starts at low levels and increases linearly at the slowest pace. These data provide evidence for graded variation of the T1w/T2w ratio along the S-A axis that may reflect cortical myelination changes during adolescence underlying the development of complex information processing and psychological functioning. We discuss the implications of these results as well as caveats in interpreting magnetic resonance imaging (MRI)-based estimates of myelination.SIGNIFICANCE STATEMENT Myelin is a lipid membrane that is essential to healthy brain function. Myelin wraps axons to increase neural signaling speed, enabling complex neuronal functioning underlying learning and cognition. Here, we characterize the developmental timing of myelination across the cerebral cortex during adolescence using a noninvasive proxy measure, T1w/T2w mapping. Our results provide new evidence demonstrating graded variation across the cortex in the timing of T1w/T2w changes during adolescence, with rapid T1w/T2w increases in lower-order sensory areas and gradual T1w/T2w increases in higher-order association areas. This spatial pattern of microstructural brain development closely parallels the sensorimotor-to-association axis of cortical organization and plasticity during ontogeny.

Fluctuations in behavior and affect in college students measured using deep phenotyping.

College students commonly experience psychological distress when faced with intensified academic demands and changes in the social environment. Examining the nature and dynamics of students' affective and behavioral experiences can help us better characterize the correlates of psychological distress. Here, we leveraged wearables and smartphones to study 49 first-year college students continuously throughout the academic year. Affect and sleep, academic, and social behavior showed substantial changes from school semesters to school breaks and from weekdays to weekends. Three student clusters were identified with behavioral and affective dissociations and varying levels of distress throughout the year. While academics were a common stressor for all, the cluster with highest distress stood out by frequent report of social stress. Moreover, the frequency of reporting social, but not academic, stress predicted subsequent clinical symptoms. Two years later, during the COVID-19 pandemic, the first-year cluster with highest distress again stood out by frequent social stress and elevated clinical symptoms. Focus on sustained interpersonal stress, relative to academic stress, might be especially helpful to identify students at heightened risk for psychopathology.

Effect of frequent assessment of suicidal thinking on its incidence and severity: high-resolution real-time monitoring study.

Researchers, clinicians and patients are increasingly using real-time monitoring methods to understand and predict suicidal thoughts and behaviours. These methods involve frequently assessing suicidal thoughts, but it is not known whether asking about suicide repeatedly is iatrogenic. We tested two questions about this approach: (a) does repeatedly assessing suicidal thinking over short periods of time increase suicidal thinking, and (b) is more frequent assessment of suicidal thinking associated with more severe suicidal thinking? In a real-time monitoring study (n = 101 participants, n = 12 793 surveys), we found no evidence to support the notion that repeated assessment of suicidal thoughts is iatrogenic.

Childhood adversities and suicidal thoughts and behaviors among first-year college students: results from the WMH-ICS initiative.

PURPOSE: To investigate the associations of childhood adversities (CAs) with lifetime onset and transitions across suicidal thoughts and behaviors (STB) among incoming college students. METHODS: Web-based self-report surveys administered to 20,842 incoming college students from nine countries (response rate 45.6%) assessed lifetime suicidal ideation, plans and attempts along with seven CAs: parental psychopathology, three types of abuse (emotional, physical, sexual), neglect, bully victimization, and dating violence. Logistic regression estimated individual- and population-level associations using CA operationalizations for type, number, severity, and frequency. RESULTS: Associations of CAs with lifetime ideation and the transition from ideation to plan were best explained by the exact number of CA types (OR range 1.32-52.30 for exactly two to seven CAs). Associations of CAs with a transition to attempts were best explained by the frequency of specific CA types (scaled 0-4). Attempts among ideators with a plan were significantly associated with all seven CAs (OR range 1.16-1.59) and associations remained significant in adjusted analyses with the frequency of sexual abuse (OR = 1.42), dating violence (OR = 1.29), physical abuse (OR = 1.17) and bully victimization (OR = 1.17). Attempts among ideators without plan were significantly associated with frequency of emotional abuse (OR = 1.29) and bully victimization (OR = 1.36), in both unadjusted and adjusted analyses. Population attributable risk simulations found 63% of ideation and 30-47% of STB transitions associated with CAs. CONCLUSION: Early-life adversities represent a potentially important driver in explaining lifetime STB among incoming college students. Comprehensive intervention strategies that prevent or reduce the negative effects of CAs may reduce subsequent onset of STB.

Bayesian explanatory additive IRT models.

In this article we extend the framework of explanatory mixed IRT models to a more general class called explanatory additive IRT models. We do this by augmenting the linear predictors in terms of smooth functions. This development offers many new modeling options such as the inclusion of nonlinear covariate effects, the specification of various temporal and spatial dependency patterns, and parameter partitioning across covariates. We use integrated nested Laplace approximation (INLA) for accurate and computationally efficient estimation of the parameters. Uninformative, weakly informative, and informative prior settings for the hyperparameters are discussed. Running time experiments and Monte Carlo parameter recovery simulations are performed in order to study the accuracy and computational efficiency of INLA when applied to the proposed explanatory additive IRT model class. Using a real-life dataset, a variety of application scenarios is explored, and the results are compared with classical maximum likelihood estimation when possible. R code is included in the supplemental materials to allow readers to fully reproduce the examples computed in the paper.

Functional assessment of restrictive eating: A three-study clinically heterogeneous and transdiagnostic investigation.

Restrictive eating is common and associated with negative psychological outcomes across the life span and eating disorder (ED) severity levels. Little is known about functional processes that maintain restriction, especially outside of narrow diagnostic categories (e.g., anorexia nervosa). Here, we extend research on operant four-function models (identifying automatic negative, automatic positive, social negative, and social positive reinforcement functions) that have previously been applied to nonsuicidal self-injury (NSSI), binge eating, and purging to restricting. We assessed restrictive eating functions in three samples: clinically heterogeneous adolescents (Study 1: N = 457), transdiagnostic adults (Study 2: N = 145), and adults with acute or recently weight-restored anorexia nervosa (Study 3: N = 45). Study 1 indicated the four-function model was a good fit for restricting (root mean square error of approximation [RMSEA] = .06, Tucker-Lewis index [TLI] = .88). This factor structure replicated in Study 2 (comparative fit index [CFI] = .97, RMSEA = .07, TLI = .97, standardized root mean square residual [SRMR] = .09). Unlike NSSI, binge eating, and purging, which have been found to primarily serve automatic negative reinforcement functions, all three present studies found automatic positive reinforcement was most highly endorsed (by up to 85% of participants). In Studies 1 and 3, automatic functions were associated with poorer emotion regulation (ps < .05). In Study 1, social functions were associated with less social support (ps < .001). Across studies, automatic functions were associated with greater restriction ps < .05). Functions varied slightly by ED diagnosis. Across ED presentation, severity, and developmental stage, restrictive eating may be largely maintained by automatic positive reinforcement, with some variability across presentations. Continued examination of restrictive eating functions will establish processes that maintain restriction, allowing more precise treatment targeting for these problematic behaviors. (PsycInfo Database Record (c) 2021 APA, all rights reserved).