Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease caused by deficiency of the protein dystrophin and affects approximately 1/3500 boys. Basic/translational studies of exercise effects in DMD have been conducted for decades, but with often contradictory results concerning benefit vs. detriment especially for cardiac muscle. However, these studies have been exclusively performed in a mouse model which does not fully recapitulate the DMD cardiac phenotype. Here we present the first known characterization of exercise and physical function in a new DMD mdx rat model that better mimics human DMD. DMD mdx rats (n=6) and healthy, sibling wild types (WT, n=9) were compared in this study. I performed a battery of functional and exercise tests  when the rats were at 14-15 weeks of age, including max treadmill endurance, volitional wheel running distance, forelimb grip strength, and in-vivo hindlimb force testing. Total work performed in treadmill endurance testing was lower for DMD mdx (2.6±0.3 Kpm) vs. WT (29.3±2.2 Kpm), p<0.001. 24-hr wheel running distance was lower for DMD mdx (702±65m) vs. WT (1038±66m), p<0.001. Forelimb grip strength was lower for DMD mdx (211±16g) vs. WT (318±13g), p<0.001. Finally, in electrically-stimulated in-vivo hindlimb force testing, both muscular endurance (% of initial force at 200-s) and peak torque (at 120Hz) were less in DMDmdx (55±2%, 0.33±0.02nM*m/g) vs. WT (69±2%, 0.45±0.030nM*m/g) p<0.01. Capacity for volitional and forced exercise is severely impaired in the novel DMD rat, congruent with limitations observed in functional muscular strength and endurance. Ongoing work is examining exercise adaptations and cardiac responses in this model which may better represent training responses in DMD patients and be useful for establishing exercise guidelines in this population.

In 2020 marijuana use among college students was at an all-time high with 44% reporting using in the past year. Research demonstrates individuals with ADHD are at risk for increased marijuana use later in life. Additionally, some studies demonstrate self-reported symptoms of ADHD among undiagnosed college students prospectively relate to increased marijuana use, which was mediated by changes in perceptions of typical peer marijuana use (i.e., descriptive norms). However, this is complicated by frequent marijuana use being linked to issues with attention, impulsivity, and memory; all captured by self-reported ADHD measures. This study will evaluate bidirectional relations between ADHD-related symptoms, marijuana descriptive norms, and marijuana use among college students. Data collection is in progress and will be completed in March 2022 as part of a larger study. Students completed assessments at baseline, 6 months, and 12 months. A cross-lagged panel model will be conducted in R using the lavaan package to evaluate the bidirectional associations over a 1-year period, as well as test whether marijuana norms at 6 months mediate the longitudinal associations between ADHD-related symptoms and marijuana use from baseline to 12 months.  We hypothesize those reporting more ADHD-related symptoms will use marijuana more frequently 6 months later. Additionally, those who use marijuana more frequently will report more ADHD-related symptoms after 6 months. We also hypothesize that those experiencing more ADHD-related symptoms at baseline will have increased marijuana norms at 6 months and subsequent greater marijuana use at 12 months. This study attempts to disentangle the bidirectional associations between ADHD-related symptoms, marijuana norms, and marijuana use over a one-year period. Conclusions and future directions for research will be presented. Additionally, this study may have implications for norms-based interventions to better address memory, impulsivity, and other ADHD-related symptoms in association with marijuana use and perceptions.

Soldiers who are transitioning to civilian life have alarmingly high rates of suicide, alcohol abuse, and mental illness. There are multiple facets that may influence these poor outcomes for veterans. Organizational dissatisfaction is a risk factor for poor mental health and lack of access to mental health support for veterans, but this has yet to be studied in-depth. The aim of this project is to assess how demographic variables and organizational dynamics impact mental health during the transition process. First, we will use preliminary data from The Network Study, one of the first longitudinal studies to follow the mental health, alcohol use, and socioeconomic stressors of service members as they transition out of the Army. Multiple regression will be used to analyze the influence of interpersonal support and conflict within the Army on depressive and anxiety symptoms. Mental health symptoms were measured by the PHQ-9 and GAD-7, two common screening questionnaires used to briefly assess depressive and anxiety symptoms, respectively. We will additionally assess various demographic variables as moderators. Next, findings will be used to develop questions for qualitative interviews to be conducted with recent veterans. We predict there will be a positive association between organizational support and positive mental health outcomes, and qualitative interviews will show lower work-related stress and increased access to mental health supports as major themes for those with positive work relationships. In line with previous research, we predict these associations and themes will be strongest for women, racial and ethnic minorities, and those of lower rank. Support and intraunit conflict are potentially modifiable factors, so our research demonstrates a potential pathway for prevention of negative mental health outcomes for veterans.