Predicting physical activity by the personality styles of the five-factor model.

OBJECTIVE: Low neuroticism, high extraversion, and high conscientiousness are related to physical activity (PA). We tested whether the small size and heterogeneity of these relationships result because personality traits influence one another as well as because some narrow facets rather than the broad domains contain more specific variance relevant to PA. METHOD: Participants were men and women enrolled in the University of North Carolina Alumni Heart Study who completed the Revised NEO Personality Inventory (NEO-PI-R) and reported their past month's average activity on an 8-point scale. In Study 1, we examined prospective correlations between the five NEO-PI-R domains and PA. In Studies 2 and 3, we used multinomial logistic regression to examine associations between PA and trait pair combinations (personality styles) controlling for age, sex, educational achievement, relationship status, and depression. RESULTS: Study 1 revealed that lower neuroticism (N) and agreeableness (A) and higher conscientiousness (C) predicted more PA. Taken together, Studies 2 and 3 found that the combination of high Extraversion (E) and high openness (O) was related to higher PA and that combinations of low E and high A and low E and low C were related to lower PA. Study 3, which examined the activity facet of E (E4), found that E4 is an important driver of E-PA associations. CONCLUSIONS: Personality traits do not operate in isolation. They may influence how other traits are expressed and such nonadditive effects can impact PA. Assessment of personality styles could help to identify individuals at risk for PA avoidance and may be useful for developing personalized interventions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Genome-Wide Genetic Analysis of Dropout in a Controlled Exercise Intervention in Sedentary Adults With Overweight or Obesity and Cardiometabolic Disease.

BACKGROUND: Despite the benefits of exercise, many individuals are unable or unwilling to adopt an exercise intervention. PURPOSE: The purpose of this analysis was to identify putative genetic variants associated with dropout from exercise training interventions among individuals in the STRRIDE trials. METHODS: We used a genome-wide association study approach to identify genetic variants in 603 participants initiating a supervised exercise intervention. Exercise intervention dropout occurred when a subject withdrew from further participation in the study or was otherwise lost to follow-up. RESULTS: Exercise intervention dropout was associated with a cluster of single-nucleotide polymorphisms with the top candidate being rs722069 (T/C, risk allele = C) (unadjusted p = 2.2 × 10-7, odds ratio = 2.23) contained within a linkage disequilibrium block on chromosome 16. In Genotype-Tissue Expression, rs722069 is an expression quantitative trait locus of the EARS2, COG7, and DCTN5 genes in skeletal muscle tissue. In subsets of the STRRIDE genetic cohort with available muscle gene expression (n = 37) and metabolic data (n = 82), at baseline the C allele was associated with lesser muscle expression of EARS2 (p < .002) and COG7 (p = .074) as well as lesser muscle concentrations of C2- and C3-acylcarnitines (p = .026). CONCLUSIONS: Our observations imply that exercise intervention dropout is genetically moderated through alterations in gene expression and metabolic pathways in skeletal muscle. Individual genetic traits may allow the development of a biomarker-based approach for identifying individuals who may benefit from more intensive counseling and other interventions to optimize exercise intervention adoption. CLINICAL TRIAL INFORMATION: STRRIDE I = NCT00200993; STRRIDE AT/RT = NCT00275145; STRRIDE-PD = NCT00962962.

Regular participation in exercise can provide a myriad of health benefits. Although individuals recognize these benefits, many are unable or unwilling to adopt an exercise intervention once initiated. The purpose of this analysis was to identify genetic variants associated with dropout from an exercise training intervention. We found exercise intervention dropout to be genetically moderated through changes in gene expression and metabolic pathways in muscle. Thus, individual genetic traits may allow for the development of a biomarker-based targeted approach for identifying individuals who may benefit from more intensive counseling and interventions to optimize the adoption of an exercise intervention program.

Sensory over-responsivity and orbitofrontal cortex connectivity in obsessive-compulsive disorder.

BACKGROUND: Sensory over-responsivity (SOR) in obsessive-compulsive disorder (OCD) is associated with illness severity and functional impairment. However, the neural substrates of SOR in OCD have not yet been directly probed. METHODS: We examined resting-state global functional connectivity markers of SOR in 119 adults with OCD utilizing the CONN-fMRI Functional Connectivity Toolbox for SPM (v21a). We quantified SOR with the sensory sensitivity and sensory avoiding subscales of the Adult and Adolescent Sensory Profile (AASP). We also measured: OCD severity, with the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and Obsessive-Compulsive Inventory-Revised (OCI-R); sensory phenomena with the Sensory Phenomena Scale (SPS); general anxiety, with the Beck Anxiety Inventory (BAI); and depressive symptomatology, with Quick Inventory of Depressive Symptoms, Self-Report (QIDS-SR). RESULTS: There was a significant positive relationship of SOR with global connectivity in anterior and medial OFC (Brodmanns area 11, k = 154, x = 14, y = 62, z = -18, whole-brain corrected at FWE p < 0.05). LIMITATIONS: Future investigations should explore neural responses to sensory stimulation tasks in OCD and compare findings with those obtained in other conditions also characterized by high SOR, such as autism spectrum disorder. CONCLUSIONS: This study implicates OFC functional connectivity as a neurobiological mechanism of SOR in OCD and suggests that the substrates of SOR in OCD may be dissociable from both that of other symptoms in OCD, and SOR in other disorders. With replication and extension, the finding may be leveraged to develop and refine treatments for OCD and investigate the pathophysiology of SOR in other conditions.

Demographic, Clinical, and Psychosocial Predictors of Exercise Adherence: The STRRIDE Trials.

Purpose: To identify baseline demographic, clinical, and psychosocial predictors of exercise intervention adherence in the Studies of a Targeted Risk Reduction Intervention through Defined Exercise (STRRIDE) trials. Methods: A total of 947 adults with dyslipidemia or prediabetes were enrolled into an inactive control group or one of ten exercise interventions with doses of 10-23 kcal/kg/week, intensities of 40-80% of peak oxygen consumption, and training for 6-8-months. Two groups included resistance training. Mean percent aerobic and resistance adherence were calculated as the amount completed divided by the prescribed weekly minutes or total sets of exercise times 100, respectively. Thirty-eight clinical, demographic, and psychosocial measures were considered for three separate models: 1) clinical + demographic factors, 2) psychosocial factors, and 3) all measures. A backward bootstrapped variable selection algorithm and multiple regressions were performed for each model. Results: In the clinical and demographic measures model (n=947), variables explained 16.7% of the variance in adherence (p<0.001); lesser fasting glucose explained the greatest amount of variance (partial R2 = 3.2%). In the psychosocial factors model (n=561), variables explained 19.3% of the variance in adherence (p<0.001); greater 36-Item Short Form Health Survey (SF-36) physical component score explained the greatest amount of variance (partial R2 = 8.7%). In the model with all clinical, demographic, and psychosocial measures (n=561), variables explained 22.1% of the variance (p<0.001); greater SF-36 physical component score explained the greatest amount of variance (partial R2 = 8.9%). SF-36 physical component score was the only variable to account for >5% of the variance in adherence in any of the models. Conclusions: Baseline demographic, clinical, and psychosocial variables explain approximately 22% of the variance in exercise adherence. The limited variance explained suggests future research should investigate additional measures to better identify participants who are at risk for poor exercise intervention adherence.

A Randomized Controlled Trial of Repeated Ketamine Administration for Chronic Posttraumatic Stress Disorder.

Objective: Posttraumatic stress disorder (PTSD) is a chronic and disabling disorder, for which available pharmacotherapies have limited efficacy. The authors' previous proof-of-concept randomized controlled trial of single-dose intravenous ketamine infusion in individuals with PTSD showed significant and rapid PTSD symptom reduction 24 hours postinfusion. The present study is the first randomized controlled trial to test the efficacy and safety of repeated intravenous ketamine infusions for the treatment of chronic PTSD. Methods: Individuals with chronic PTSD (N=30) were randomly assigned (1:1) to receive six infusions of ketamine (0.5 mg/kg) or midazolam (0.045 mg/kg) (psychoactive placebo control) over 2 consecutive weeks. Clinician-rated and self-report assessments were administered 24 hours after the first infusion and at weekly visits. The primary outcome measure was change in PTSD symptom severity, as assessed with the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5), from baseline to 2 weeks (after completion of all infusions). Secondary outcome measures included the Impact of Event Scale-Revised, the Montgomery-Åsberg Depression Rating Scale (MADRS), and side effect measures. Results: The ketamine group showed a significantly greater improvement in CAPS-5 and MADRS total scores than the midazolam group from baseline to week 2. At week 2, the mean CAPS-5 total score was 11.88 points (SE=3.96) lower in the ketamine group than in the midazolam group (d=1.13, 95% CI=0.36, 1.91). Sixty-seven percent of participants in the ketamine group were treatment responders, compared with 20% in the midazolam group. Among ketamine responders, the median time to loss of response was 27.5 days following the 2-week course of infusions. Ketamine infusions were well tolerated overall, without serious adverse events. Conclusions: This randomized controlled trial provides the first evidence of efficacy of repeated ketamine infusions in reducing symptom severity in individuals with chronic PTSD. Further studies are warranted to understand ketamine's full potential as a treatment for chronic PTSD.Reprinted from Am J Psychiatry 2021; 178:193-202, with permission from American Psychiatric Association Publishing. Copyright © 2021.

Effects of exercise amount and intensity versus a combined exercise and lifestyle intervention on metabolic syndrome in adults with prediabetes: a STRRIDE-PD randomized trial.

The purpose of this secondary analysis was to determine what portion of the effects of a Diabetes Prevention Program-like intervention on metabolic syndrome (MetS) could be achieved with exercise alone, as well as to determine the relative importance of exercise intensity and amount to the total exercise effect on MetS. Sedentary, overweight adults with prediabetes were randomly assigned to one of four 6-month interventions: 1) low-amount/moderate-intensity (10 kcal/kg/week at 50% peak V˙O2); 2) high-amount/moderate-intensity (16 kcal/kg/week at 50% peak V˙O2); 3) high-amount/vigorous-intensity (16 kcal/kg/week at 75% peak V˙O2); or 4) diet (7% weight loss) plus low-amount/moderate-intensity (10 kcal/kg/week at 50% peak V˙O2). The primary outcome of this secondary analysis was change in the MetS z-score. A total of 130 participants had complete data for all five Adult Treatment Panel (ATP) III MetS criteria. The diet-and-exercise group statistically outperformed the MetS z-score and the ATP III score compared to the exercise alone group. Aerobic exercise alone achieved 24%-50% of the total effect of the combined diet-and-exercise intervention on the MetS score. Low-amount moderate-intensity exercise quantitatively performed equal to or better than the interventions of high-amount moderate-intensity or high-amount vigorous-intensity exercise in improving the MetS score. The combined diet-and-exercise intervention remains more efficacious in improving the MetS z-score. However, all three exercise interventions alone showed improvements in the MetS z-score, suggesting that a modest amount of moderate-intensity exercise is all that is required to achieve approximately half the effect of a diet-and-exercise intervention on the MetS. Clinical Trial Registration: clinicaltrials.gov, identifier NCT00962962.

Failures of Urge Suppression in Obsessive-Compulsive Disorder: Behavioral Modeling Using a Blink Suppression Task.

Many individuals with obsessive-compulsive disorder (OCD) report sensory-based urges (e.g. 'not-just-right experiences') in addition to, or instead of, concrete fear-based obsessions. These sensations may be comparable to normative "urges-for-action" (UFA), such as the urge to blink. While research has identified altered functioning of brain regions related to UFA in OCD, little is known about behavioral patterns of urge suppression in the disorder. Using an urge-to-blink task as a model for sensory-based urges, this study compared failures of urge suppression between OCD patients and controls by measuring eyeblinks during 60-second blocks of instructed blink suppression. Cox shared frailty models estimated the hazard of first blinks during each 60-second block and recurrent blinks following each initial erroneous blink. OCD patients demonstrated a higher hazard of first and recurrent blinks compared to controls, suggesting greater difficulty resisting repetitive sensory-based urges. Within OCD, relationships between task outcomes and symptom severity were inconsistent. Findings provide support for a deficit in delaying initial urge-induced actions and terminating subsequent actions in OCD, which is not clearly related to clinical heterogeneity. Elucidating the nature of behavioral resistance to urges is relevant for informing conceptualizations of obsessive-compulsive psychopathology and optimizing treatment outcomes.

Race and sex differences in dropout from the STRRIDE trials.

Purpose: To determine if race and sex differences exist in determinants and timing of dropout among individuals enrolled in an exercise and/or caloric restriction intervention. Methods: A total of 947 adults with dyslipidemia (STRRIDE I, STRRIDE AT/RT) or prediabetes (STRRIDE-PD) were randomized to either inactive control or to 1 of 10 exercise interventions, ranging from doses of 8-23 kcal/kg/week, intensities of 50%-75% V˙O2 peak, and durations of 6-8 months. Two groups included resistance training, and one included a dietary intervention (7% weight loss goal). Dropout was defined as an individual withdrawn from the study, with the reasons for dropout aggregated into determinant categories. Timing of dropout was defined as the last session attended and aggregated into phases (i.e., "ramp" period to allow gradual adaptation to exercise prescription). Utilizing descriptive statistics, percentages were generated according to categories of determinants and timing of dropout to describe the proportion of individuals who fell within each category. Results: Black men and women were more likely to be lost to follow-up (Black men: 31.3% and Black women: 19.6%), or dropout due to work responsibilities (15.6% and 12.5%), "change of mind" (12.5% and 8.9%), transportation issues (6.3% and 3.6%), or reported lack of motivation (6.3% and 3.6%). Women in general noted lack of time more often than men as a reason for dropout (White women: 22.4% and Black women: 22.1%). Regardless of race and sex, most participants dropped out during the ramp period of the exercise intervention; with Black women (50%) and White men (37.1%) having the highest dropout rate during this period. Conclusion: These findings emphasize the importance of targeted retention strategies when aiming to address race and sex differences that exist in determinants and timing of dropout among individuals enrolled in an exercise and/or caloric restriction intervention.

Change in circulating klotho in response to weight loss, with and without exercise, in adults with overweight or obesity.

Introduction: Klotho is a protein associated with protection from aging-related diseases and health conditions. Obesity is associated with lower Klotho concentrations. Thus, this secondary analysis of adults with obesity examined 1) the change in serum Klotho concentration in response to a behavioral weight loss intervention by the magnitude of weight loss achieved; and 2) the association among serum Klotho concentration and weight, body composition, and cardiorespiratory fitness. Methods: Participants were randomized to either diet alone (DIET), diet plus 150 min of physical activity per week (DIET + PA150), or diet plus 250 min of physical activity per week (DIET + PA250). Participants [n = 152; age: 45.0 ± 7.9 years; body mass index (BMI): 32.4 ± 3.8 kg/m2] included in this secondary analysis provided blood samples at baseline, 6-, and 12 months, and were classified by weight loss response (Responder: achieved ≥10% weight loss at 6 or 12 months; Non-responder: achieved <5% weight loss at both 6 and 12 months). Serum Klotho was measured using a solid-phase sandwich enzyme-linked immunosorbent assay (ELISA). Analyses of covariance (ANCOVA's) were used to examine changes in weight, body composition, cardiorespiratory fitness, and Klotho concentration by weight loss response across the 12-month weight loss intervention. Results: Responders had a greater reduction in measures of weight and body composition, and a greater increase in cardiorespiratory fitness, compared to Non-Responders (p < 0.05). Change in Klotho concentration differed between Responders and Non-Responders (p < 0.05), with the increase in Klotho concentration from baseline to 6 months for Responders being statistically significant. The 6-month change in Klotho concentration was inversely associated with the 6-month change in weight (r s = -0.195), BMI (r s = -0.196), fat mass (r s = -0.184), and waist circumference (r s = -0.218) (p-values <0.05). Discussion: Findings provide evidence within the context of a behavioral intervention, with and without exercise, that change in Klotho concentration is significantly different between adults with weight loss ≥10% compared to <5% across 12 months. These findings suggest that weight loss and reduction in fat mass may be favorably associated with the change in Klotho concentration. This may reduce the risk of negative health consequences associated with accelerated aging in middle-aged adults.

Ketamine versus ECT for Nonpsychotic Treatment-Resistant Major Depression.

BACKGROUND: Electroconvulsive therapy (ECT) and subanesthetic intravenous ketamine are both currently used for treatment-resistant major depression, but the comparative effectiveness of the two treatments remains uncertain. METHODS: We conducted an open-label, randomized, noninferiority trial involving patients referred to ECT clinics for treatment-resistant major depression. Patients with treatment-resistant major depression without psychosis were recruited and assigned in a 1:1 ratio to receive ketamine or ECT. During an initial 3-week treatment phase, patients received either ECT three times per week or ketamine (0.5 mg per kilogram of body weight over 40 minutes) twice per week. The primary outcome was a response to treatment (i.e., a decrease of ≥50% from baseline in the score on the 16-item Quick Inventory of Depressive Symptomatology-Self-Report; scores range from 0 to 27, with higher scores indicating greater depression). The noninferiority margin was -10 percentage points. Secondary outcomes included scores on memory tests and patient-reported quality of life. After the initial treatment phase, the patients who had a response were followed over a 6-month period. RESULTS: A total of 403 patients underwent randomization at five clinical sites; 200 patients were assigned to the ketamine group and 203 to the ECT group. After 38 patients had withdrawn before initiation of the assigned treatment, ketamine was administered to 195 patients and ECT to 170 patients. A total of 55.4% of the patients in the ketamine group and 41.2% of those in the ECT group had a response (difference, 14.2 percentage points; 95% confidence interval, 3.9 to 24.2; P<0.001 for the noninferiority of ketamine to ECT). ECT appeared to be associated with a decrease in memory recall after 3 weeks of treatment (mean [±SE] decrease in the T-score for delayed recall on the Hopkins Verbal Learning Test-Revised, -0.9±1.1 in the ketamine group vs. -9.7±1.2 in the ECT group; scores range from -300 to 200, with higher scores indicating better function) with gradual recovery during follow-up. Improvement in patient-reported quality-of-life was similar in the two trial groups. ECT was associated with musculoskeletal adverse effects, whereas ketamine was associated with dissociation. CONCLUSIONS: Ketamine was noninferior to ECT as therapy for treatment-resistant major depression without psychosis. (Funded by the Patient-Centered Outcomes Research Institute; ELEKT-D ClinicalTrials.gov number, NCT03113968.).

Cognitive Neuroscience of Obsessive-Compulsive Disorder.

Cognitive neuroscientific research has the ability to yield important insights into the complex neurobiological processes underlying obsessive-compulsive disorder (OCD). This article provides an updated review of neuroimaging studies in seven neurocognitive domains. Findings from the literature are discussed in the context of obsessive-compulsive phenomenology and treatment. Expanding our knowledge of the neural mechanisms involved in OCD could help optimize treatment outcomes and guide the development of novel interventions.

Effect of behavioral weight-loss program on biomarkers of cardiometabolic disease risk: Heart Health Study randomized trial.

OBJECTIVE: This study aimed to determine whether novel biomarkers of cardiometabolic health improve in response to a 12-month behavioral weight-loss intervention and to compare benefits of diet alone with diet plus physical activity for these biomarkers. METHODS: Participants (N = 374) were randomized to either diet alone (DIET), diet plus 150 min/wk of prescribed moderate-intensity physical activity (DIET + PA150), or diet plus 250 min/wk of prescribed moderate-intensity physical activity (DIET + PA250). Biomarker concentrations were determined using nuclear magnetic resonance spectroscopy. Mixed models assessed for a time effect, group effect, or group by time interaction. RESULTS: All groups significantly improved body weight (time: p < 0.0001), Lipoprotein Insulin Resistance Index score (time: p < 0.0001), Diabetes Risk Index score (time: p < 0.0001), branched-chain amino acid concentration (time: p < 0.0001), and GlycA concentration (time: p < 0.0001), with no group effect or group by time interactions. CONCLUSIONS: All intervention groups prompted a notable beneficial change among biomarkers of insulin resistance and cardiometabolic health. However, the addition of at least moderate-intensity physical activity to a diet-only intervention did not provide any additional benefit. These findings highlight that an average weight loss of approximately 10% profoundly impacts biomarkers of insulin resistance and cardiometabolic disease in adults with overweight or obesity.

Clinical Predictors of Adherence to Exercise Training Among Individuals With Heart Failure: THE HF-ACTION STUDY.

PURPOSE: Suboptimal adherence is a major limitation to achieving the benefits of exercise interventions, and our ability to predict and improve adherence is limited. The purpose of this analysis was to identify baseline clinical and demographic characteristics predicting exercise training adherence in the HF-ACTION study cohort. METHODS: Adherence to exercise training, defined by the total duration of exercise performed (min/wk), was evaluated in 1159 participants randomized to the HF-ACTION exercise intervention. More than 50 clinical, demographic, and exercise testing variables were considered in developing a model of the min/wk end point for 1-3 mo (supervised training) and 10-12 mo (home-based training). RESULTS: In the multivariable model for 1-3 mo, younger age, lower income, more severe mitral regurgitation, shorter 6-min walk test distance, lower exercise capacity, and Black or African American race were associated with poorer exercise intervention adherence. No variable accounted for >2% of the variance and the adjusted R2 for the final model was 0.14. Prediction of adherence was similarly limited for 10-12 mo. CONCLUSIONS: Clinical and demographic variables available at the initiation of exercise training provide very limited information for identifying patients with heart failure who are at risk for poor adherence to exercise interventions.

Understanding the Associations among Social Vulnerabilities, Indigenous Peoples, and COVID-19 Cases within Canadian Health Regions.

Indigenous Peoples are at an increased risk for infectious disease, including COVID-19, due to the historically embedded deleterious social determinants of health. Furthermore, structural limitations in Canadian federal government data contribute to the lack of comparative rates of COVID-19 between Indigenous and non-Indigenous people. To make visible Indigenous Peoples' experiences in the public health discourse in the midst of COVID-19, this paper aims to answer the following interrelated research questions: (1) What are the associations of key social determinants of health and COVID-19 cases among Canadian health regions? and (2) How do these relationships relate to Indigenous communities? As both proximal and distal social determinants of health conjointly contribute to COVID-19 impacts on Indigenous health, this study used a unique dataset assembled from multiple sources to examine the associations among key social determinants of health characteristics and health with a focus on Indigenous Peoples. We highlight key social vulnerabilities that stem from systemic racism and that place Indigenous populations at increased risk for COVID-19. Many Indigenous health issues are rooted in the historical impacts of colonization, and partially invisible due to systemic federal underfunding in Indigenous communities. The Canadian government must invest in collecting accurate, reliable, and disaggregated data on COVID-19 case counts for Indigenous Peoples, as well as in improving Indigenous community infrastructure and services.

Differential Effects of Amount, Intensity, and Mode of Exercise Training on Insulin Sensitivity and Glucose Homeostasis: A Narrative Review.

As type 2 diabetes remains a leading cause of morbidity and mortality, identifying the most appropriate preventive treatment early in the development of disease is an important public health matter. In general, lifestyle interventions incorporating exercise and weight loss via caloric restriction improve cardiometabolic risk by impacting several key markers of insulin sensitivity and glucose homeostasis. However, variations in the effects of specific types of exercise interventions on these markers have led to conflicting results surrounding the optimal amount, intensity, and mode of exercise for optimal effects. Moreover, the addition of weight loss via caloric restriction to exercise interventions appears to differentially impact changes in body composition, metabolism, and insulin sensitivity compared to exercise alone. Determining the optimal amount, intensity, and mode of exercise having the most beneficial impact on glycemic status is both: (1) clinically important to provide guidelines for appropriate exercise prescription; and (2) physiologically important to understand the pathways by which exercise-with and without weight loss-impacts glycemic status to enhance precision lifestyle medicine. Thus, the purposes of this narrative review are to: (1) summarize findings from the three Studies of a Targeted Risk Reduction Intervention through Defined Exercise (STRRIDE) randomized trials regarding the differential effects of exercise amount, intensity, and mode on insulin action and glucose homeostasis markers; and (2) compare the STRRIDE findings to other published dose-response exercise trials in order to piece together the various physiologic pathways by which specific exercise interventions-with or without weight loss-impact glycemic status.

Determinants of Dropout from and Variation in Adherence to an Exercise Intervention: The STRRIDE Randomized Trials.

Purpose: This study aimed to characterize the timing and self-reported determinants of exercise dropout among sedentary adults with overweight or obesity. We also sought to explore variations in adherence among individuals who completed a 6- to 8-month structured exercise intervention. Methods: A total of 947 adults with dyslipidemia [STRRIDE I, STRRIDE AT/RT] or prediabetes [STRRIDE-PD] were enrolled to either control or to one of 10 exercise interventions, ranging from doses of 8-23 kcal/kg/week; intensities of 50%-75% V̇O2 peak; and durations of 6-8 months. Two groups included resistance training and one included dietary intervention (7% weight loss goal). Dropout was defined as an individual who withdrew from the study due a variety of determinants. Timing of intervention dropout was defined as the last session attended and categorized into phases. Exercise training adherence was calculated by dividing weekly minutes or total sets of exercise completed by weekly minutes or total sets of exercise prescribed. General linear models were used to characterize the associations between timing of dropout and determinant category. Results: Compared to exercise intervention completers (n=652), participants who dropped out (n=295) were on average non-white (98% vs. 80%, p<0.01), had higher body mass index (31.0 kg/m2 vs. 30.2 kg/m2; p<0.01), and were less fit at baseline (25.0 mg/kg/min vs. 26.7 ml/kg/min, p<0.01). Of those who dropped out, 67% did so prior to the start of or while ramping up to the prescribed exercise volume and intensity. The most commonly reported reason for dropout was lack of time (40%). Notably, among individuals who completed the ramp training period, subsequent exercise intervention adherence did not waiver over the ensuing 6-8 months of training. Conclusion: These findings are some of the first to delineate associations between the timing of dropout and dropout determinants, providing guidance to future exercise interventions to better support individuals at-risk for dropout.

Relationships between interoceptive sensibility and resting-state functional connectivity of the insula in obsessive-compulsive disorder.

Patients with obsessive-compulsive disorder (OCD) exhibit abnormality in their subjective perception of internal sensation, a process known as interoceptive sensibility (IS), as well as altered functioning of the insula, a key neural structure for interoception. We investigated the multivariate structure of IS in 77 OCD patients and 53 controls and examined associations of IS with resting-state functional connectivity (FC) of the insula within the OCD group. For each group, principal component analysis was performed on 8 subscales of the Multidimensional Assessment of Interoceptive Awareness assessing putatively "adaptive" and "maladaptive" aspects of IS. Associations between IS components and insula FC in the OCD group were evaluated using seed regions placed in each of 3 subdivisions of the insula (posterior, anterior dorsal, and anterior ventral). Behaviorally, controls showed a 2-component solution broadly categorized into "adaptive" and "maladaptive" IS, while OCD patients exhibited a 3-component solution. The general tendency to notice or be aware of sensation loaded onto an "adaptive" IS component in controls but loaded onto both "adaptive" and "maladaptive" IS components in OCD. Within OCD, insula FC was differentially associated with distinct aspects of IS, identifying network connections that could serve as future targets for the modulation of IS in OCD.

Behavioral and neural mechanisms of latent inhibition.

Fear is an adaptive emotion that serves to protect an organism against potential dangers. It is often studied using classical conditioning paradigms where a conditioned stimulus is paired with an aversive unconditioned stimulus to induce a threat response. Less commonly studied is a phenomenon that is related to this form of conditioning, known as latent inhibition. Latent inhibition (LI) is a paradigm in which a neutral cue is repeatedly presented in the absence of any aversive associations. Subsequent pairing of this pre-exposed cue with an aversive stimulus typically leads to reduced expression of a conditioned fear/threat response. In this article, we review some of the theoretical basis for LI and its behavioral and neural mechanisms. We compare and contrast LI and fear/threat extinction-a process in which a previously conditioned cue is repeatedly presented in the absence of aversive outcomes. We end with highlighting the potential clinical utility of LI. Particularly, we focus on how LI application could be useful for enhancing resilience, especially for individuals who are more prone to continuous exposure to trauma and stressful environments, such as healthcare workers and first responders. The knowledge to be gained from advancing our understanding of neural mechanisms in latent inhibition could be applicable across psychiatric disorders characterized by exaggerated fear responses and impaired emotion regulation.