Lab members and affiliates presented recent research conducted by the team - see summaries of each project below.

Recent or Lifetime Stressor Exposure? Associations With Insomnia Symptom Severity

Presented by Harrison Dickens, M.A

This study aimed to investigate the association between recent stressor exposure, lifetime stressor exposure, and insomnia symptoms severity. We hypothesized that lifetime stressor exposure and perceived lifetime stressor severity but not recent stressor exposure or severity, would be associated with greater insomnia severity. Data was collected from 134 participants (55% female, Mage = 19.83, 28% Black/African American, 34% Latinx/ Hispanic, and 39% White) completed a laboratory visit consisting of questionnaires. The Stress and Adversity Inventory (STRAIN) was used to assess lifetime and recent (past 3 months) stressor exposure and perceived stressor severity. Insomnia symptoms were measured using the Insomnia Severity Index (ISI). Race and sex were included as covariates in all models. Results from the regression model showed that recent stressor exposure was negatively associated with insomnia symptom severity (b = -1.37, SE = 0.53, p = .01). Recent stressor severity was associated with greater insomnia symptom severity (b = 0.28, SE = 0.14, p = 0.04). Neither lifetime stressor exposure nor perceived lifetime stressor severity was associated with insomnia symptom severity. Results suggest a counterintuitive negative relation between recent stressor exposure on insomnia severity, where more recent stressors are associated with less severe insomnia symptoms. However, greater recent stressor severity was associated with greater insomnia symptom severity. These findings suggest that recent stressor severity may be a better predictor of insomnia risk than both recent or lifetime stressor exposure.

Sleep Health Training Among Recent Graduates from Professional Psychology Programs

Presenting Author: Ivan Vargas, PhD

The present study aimed to quantify the extent to which recent graduates from psychology programs received training in sleep, feel comfortable providing sleep-related services, and meet basic competencies in sleep health. We surveyed 174 recent graduates (within the past 10 years) from professional psychology programs (i.e., clinical or counseling psychology PhD or PsyD) in the United States. Respondents provided demographic information and answered questions about their prior training and experiences working with patients who have sleep or circadian rhythm concerns. The sample was primarily young (mean age = 34.9 years), identified as women (81%), and White (80%). 77% of respondents reported being licensed in their state. A subset of participants (n = 35) were randomly invited to complete a brief health assessment to evaluate their sleep health knowledge and competency. Approximately three-quarters of respondents reported receiving six hours or less of formal educational training related to sleep, sleep disorders, or circadian rhythms during graduate school (73.0%) and postgraduate training (75.3%). A large proportion of respondents reported feeling not or only a “little” prepared to assess (43%) and treat (41%) sleep-related problems. Similarly, 40% reported feeling not or only a “little” confident in treating insomnia disorder. Among participants who completed the sleep health assessment, the mean score was 69.8% (SD = 9.0; Range = 40.0 – 82.9). While the present findings are primarily descriptive, they provide insight into the training, experiences, and relative competency of professional psychologists. That is, in this sample of recent graduates from psychology programs, the majority endorse having minimal training and comfort working with sleep-disordered populations. This is also consistent with more objective metrics of competency.

Hormonal Contraceptive Use and Sleep in Women

Presented by Daniella Cristando

This study aimed to identify differences in sleep quality and insomnia between women who are naturally cycling and women who use hormonal contraceptives. Data were collected from 590 young adult women (mean age = 30.5) via an online survey posted to Cloud Research Connect, a secure data collection platform. Participants were asked about menstrual health, hormonal and/or non-hormonal contraceptive usage, and sleep habits. Participants were also asked to complete the Insomnia Severity Index and Insomnia Symptom Questionnaire. There were no statistically significant differences between the hormonal contraceptive and naturally cycling groups with respect to ISI scores, F(1,5) = 2.44, r = .004, p = .11. A Chi-squares test was used to analyze ISQ scores between groups, there were no statistically significant differences, x² = 0.002, p > 0.20. Overall, hormonal contraceptive users showed a small, but not statistically significant difference in insomnia scores compared to naturally cycling women. Based on our results, we failed to replicate previous research indicating that hormonal contraceptive use was related to sleep disturbance with respect to insomnia.

The Moderating Role of Cognitive-Affective Processes on the Relationship between Sleep Reactivity and Depressive Symptoms

Presented by Emma Janes

The present study aimed to determine the roles of cognitive-affective processes, such as rumination, suppression, and cognitive reappraisal, in influencing the relationship between sleep reactivity and depressive symptoms. Cross-sectional data were collected via an online Qualtrics survey from 641 undergraduate students at the University of Arkansas (Mage=19.1 years, 68% female, 80% White). Eighty-three participants were excluded due to substantial missing data (final N = 558), and multiple imputation was used to correct for missing data. Participants completed measures of depression and anhedonia symptoms (MASQ-90), perceived stress (PSS-10), insomnia symptoms (ISI), sleep reactivity (FIRST), cognitive reappraisal and suppression (ERQ), and rumination (RRS-22). Two 3-step hierarchical multiple regressions were performed to determine whether cognitive-affective processes (rumination, suppression, cognitive reappraisal) –including their interactions with sleep reactivity– accounted for additional variance in depressive and anhedonic symptoms beyond insomnia symptoms and perceived stress. Our findings suggest that all variables had a significant main effect on depressive symptoms, however, only rumination significantly moderated the link between sleep reactivity and depression symptoms (B = .008, t(548) = 2.75, p < .01). That is, the association between sleep reactivity and depressive symptoms was greater among those with greater ruminative tendencies. The two-way interactions for suppression and cognitive reappraisal were not significant, indicating that these processes did not moderate the sleep reactivity-depression link. No cognitive-affective process significantly predicted the relationship between sleep reactivity and anhedonic symptoms. As expected, our findings supported that rumination, suppression, and cognitive reappraisal individually predict depressive symptoms. Additionally, the association between sleep reactivity and depressive symptoms was greater for individuals with greater ruminative tendencies. No cognitive-affective process was found to significantly impact the relationship between sleep reactivity and anhedonic symptoms.

Congratulations to Jamie Walker!

This past weekend, Jamie became the first student from the Sleep and Health Research Lab to officially graduate with their PhD. The University of Arkansas had its 2026 Spring Commencement on Friday, May 8th. We are all very proud of Jamie! She will complete her predoctoral internship next month and defend her dissertation in three weeks before heading off for postdoc.

Members of the Sleep and Health Research Lab recently published a review examining potential mechanistic pathways linking insomnia and depression. Their analyses spanned biological, behavioral, and cognitive affective domains, focusing specifically on hypothalamic-pituitary-adrenal (HPA) axis and inflammatory functioning, behavioral activation, and emotional processes. This review summarizes how sleep improvements via CBT-I may lead to reduced depressive symptoms, and in turn inform future research and clinical efforts to enhance the overall effectiveness of CBT-I in patients with comorbid depression.

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(Vargas et al., 2026)

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Members of the Sleep and Health Research Lab recently published their study examining the effectiveness of a single session of cognitive behavioral therapy for insomnia within an integrated primary care setting.

The findings indicate that when compared to an active attentional control group, patients who received just one-session of CBT-I showed increased sleep efficiency and reductions in total wake time, both immediately and at a 1-month follow-up. The single session CBT-I group also reported lower insomnia symptom severity at the 1-month and 3-month follow-ups.
This study aims to support the use of one-session CBT-I as a brief, and possibly scalable insomnia intervention in a primary care setting, and highlights its potential to expand access to evidence-based insomnia management with immediate and long lasting impacts on sleep health for patients who otherwise may not receive treatment.

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(Walker et al., 2026)

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During her APA-accredited internship at the Madison VA, Mara will focus on providing patient-centered care while refining the clinical expertise necessary to navigate complex psychological cases. We are incredibly proud of Mara and know she will make outstanding contributions to the program. Congratulations, Mara!

Members of the Sleep and Health Research Lab recently published a study examining public knowledge and use of insomnia treatments, with a particular focus on Cognitive Behavioral Therapy for Insomnia (CBT-I).

Findings indicate that individuals are far more familiar with, and more likely to rely on, pharmacological treatments compared to behavioral interventions such as CBT-I. Demographic differences were also observed, with women and White participants reporting greater awareness of insomnia treatments than men and individuals from other racial groups.

Overall, this study identifies significant gaps in public understanding of CBT-I and calls attention to disparities in treatment knowledge. Addressing these gaps is essential for improving access to treatment along with promoting CBT-I as a first line, evidence-based approach to treating insomnia.

Click here to read the full article.

(Assar et al., 2026)

Members of the Sleep and Health Research Lab: Arash Assar¹ and Dr. Ivan Vargas¹, et al., recently published their study examining the mechanisms linking self-compassion to sleep quality among college students.Using data from 340 undergraduates, researchers evaluated whether perceived stress, general worry, and rumination explained this relationship through simple and parallel mediation models.

Results indicated that higher self-compassion was associated with better sleep quality, and that lower perceived stress and lower general worry partially explained this relationship. Rumination did not account for unique variance once stress and worry were included in the parallel model.

These results suggest that perceived stress and general worry are key factors in the association between self-compassion and sleep quality.

Read the full article here

(Assar et al., 2026)

Notre Dame¹

Sleep disturbances during the perinatal period constitute a major public health concern, with postpartum insomnia being associated with an increased risk for psychological health issues, including postpartum depression. Despite these risks, sleep problems in new mothers are often unrecognized and go untreated.

This study will partner with pediatric providers in order to identify postpartum mothers who are experiencing insomnia during pediatric primary care visits. This distinct approach will utilize the frequency and consistency of newborn visits to better treat postpartum insomnia. Upon recruitment, we plan to engage with various maternal health stakeholders (physicians, clinic directors, patients) in order to develop an effective approach to best implement evidence-based sleep interventions, such as cognitive behavioral therapy for insomnia (CBT-I), for postpartum individuals.

Members of the Sleep and Health Research Lab: Harrison Dickens¹, Jamie Walker¹, and Dr. Ivan Vargas², et al., recently published their study investigating how the hypothalamic-pituitary-adrenal (HPA) axis responds to a laboratory-based 10% CO₂-inhalation challenge in healthy adults.

Findings indicated that inhaling CO2 can reliably activate multiple stress-response systems, involving neuroendocrine, autonomic, and emotional pathways.

Researchers evaluated salivary cortisol, heart rate, and fear/stress responses following a 5-minute CO2 challenge.

Results demonstrated (a) robust neuroendocrine, autonomic, and emotional activation in response to the CO₂ challenge, (b) significant increases in salivary cortisol for the majority of participants, and (c) sex differences and hormonal-status differences in cortisol reactivity.”

Read the full article

(Dickens et al., 2025)

University of Arkansas¹

University of Notre Dame²

• Abi Vance, B.A. , “Examining the Effects of Subjective and Objective Measures of Socioeconomic Status on Insomnia Symptoms.”
• Arash Assar, M.A., “Insomnia and Burnout in E-sports Athletes: The Mediating Roles of Competence and Relatedness.”
• Mara Egeler, M.A., “The Effect of Cognitive Behavioral Therapy for Insomnia on Depressive Symptoms: A Symptom-by-Symptom Analysis.”
• Jamie Walker, M.A., LPC, “Chronotype Moderates the Association Between Nighttime Eating and Insomnia Symptom Severity.”

We would also like to congratulate Jamie Walker on receiving the SBSM’s Intern Graduate Student Award, acknowledging her commitment and contributions to behavioral sleep medicine!

Click here if you are interested to find out whether you are eligible for the RESET study.

Daniella Cristando, a McNair Scholar at the University of Nevada, Reno, joined the Sleep and Health Research Lab through the Summer Research Opportunity Program (SROP) at the University of Notre Dame. SROP offers undergraduate students across the US 8-10 weeks of mentored research experience and training, along with opportunities to engage in a blend of professional, academic, and social programming and development.

Under the mentorship of Dr. Ivan Vargas, Daniella spent her summer working in the Sleep and Health Lab investigating two research questions: (1) negative cognitive styles and cortisol reactivity in men, and (2) how hormonal contraceptive use may influence women’s sleep health.

After two months of hardwork, Daniella presented her poster “Cognitive Vulnerability and Endocrine Responses to Stress in Men,” at the Summer Research Poster Session at Notre Dame. Her work indicated that men with a negative cognitive style may have elevated HPA-axis functioning that affects their response to daily stressors. Daniella additionally presented her second project, “Exploring the Relationship between Hormonal Contraceptive Use and Women’s Sleep,” during the 3 Minute Thesis Competition. Out of over 50 presenters, Daniella was selected as one of twelve finalists.

Dr. Vargas’s research has demonstrated the benefit of predictable bed and wake times on everyday functioning.

“...Rather than abruptly going back to the academic year sleep schedule, you can try to take those extra couple of days or the week before classes to slowly start adjusting the sleep schedule back to what it used to be,"

Additionally, Dr. Vargas was asked to share his perspective on melatonin use for children. He explained that melatonin imitates a hormone in our brains that regulates wakefulness, rather than increasing sleepiness or tiredness. As an alternative, Dr. Vargas recommends gradually shifting children’s sleep schedules, allowing one night of adjustment for every hour of difference between their current sleep routine and planned school year schedule.

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