The longitudinal mediating role of sleep in associations between COVID-19 stressors predicting mental and physical health outcomes among emerging adult college students.

The current study tested a longitudinal mediation model throughout the COVID-19 pandemic focused on whether students' housing instability stress and food/financial instability stress at the beginning of the pandemic in spring 2020 (T1) informed sleep dissatisfaction and duration in fall 2020 (T2) and, in turn, physical and mental health in spring 2021 (T3). Further, we tested whether relations varied based on students' ethnic-racial backgrounds. Participants included 879 Asian, Black, Latine, Multiracial, and White emerging adult college students (Mage = 19.95, SD = 0.33) from a large public university in the mid-Atlantic region of the United States who attended college during the COVID-19 pandemic and completed surveys about their experiences. Findings indicated a significant mediation process, such that T1 housing instability stress predicted greater T2 sleep dissatisfaction and, in turn, less physical health, greater depressive symptoms, and greater anxiety symptoms at T3. Additionally, T1 food/financial instability stress was significantly associated with less T2 sleep duration but was not, in turn, associated with any T3 outcomes. Findings did not vary by students' ethnicity/race. Results highlight that sleep dissatisfaction is an important factor that accounts for relations between COVID-19 stressors predicting mental and physical health outcomes throughout the pandemic.

Genome-wide association analyses identify 95 risk loci and provide insights into the neurobiology of post-traumatic stress disorder.

Post-traumatic stress disorder (PTSD) genetics are characterized by lower discoverability than most other psychiatric disorders. The contribution to biological understanding from previous genetic studies has thus been limited. We performed a multi-ancestry meta-analysis of genome-wide association studies across 1,222,882 individuals of European ancestry (137,136 cases) and 58,051 admixed individuals with African and Native American ancestry (13,624 cases). We identified 95 genome-wide significant loci (80 new). Convergent multi-omic approaches identified 43 potential causal genes, broadly classified as neurotransmitter and ion channel synaptic modulators (for example, GRIA1, GRM8 and CACNA1E), developmental, axon guidance and transcription factors (for example, FOXP2, EFNA5 and DCC), synaptic structure and function genes (for example, PCLO, NCAM1 and PDE4B) and endocrine or immune regulators (for example, ESR1, TRAF3 and TANK). Additional top genes influence stress, immune, fear and threat-related processes, previously hypothesized to underlie PTSD neurobiology. These findings strengthen our understanding of neurobiological systems relevant to PTSD pathophysiology, while also opening new areas for investigation.

Genetic influences on testosterone and PTSD.

Females are twice as likely to experience PTSD as compared to males. Although sex differences in prevalence are well-established, little is known about why such sex differences occur. Biological factors that vary with sex, including sex hormone production, may contribute to these differences. Considerable evidence links sex hormones, such as testosterone, to PTSD risk though less is known about the shared genetic underpinnings. The objective of the present study was to test for genetic relationships between testosterone and PTSD. To do so, we used summary statistics from large, publicly available genetic consortia to conduct linkage disequilibrium score regression to estimate the genetic correlations between PTSD and testosterone in males and females, and two-sample, bi-directional Mendelian randomization to examine potential causal relationships of testosterone on PTSD and the reverse. Heritability estimates of testosterone were significantly higher in males (0.17, SE = 0.02) than females (0.11, SE = 0.01; z = 2.46, p = 00.01). The correlation between testosterone and PTSD was negative in males (rg = -0.11, SE = 0.02, p = 6.7 x 10-6), but not significant in females (rg = 0.002, SE = 0.03, p = 0.95). MR analyses found no evidence of a causal effect of testosterone on PTSD or the reverse. Findings are consistent with phenotypic literature suggesting a relationship between testosterone and PTSD that may be sex-specific. This work provides early evidence of a relationship between testosterone and PTSD genotypically and suggests an avenue for future research that will enable a better understanding of disparities in PTSD.

Interpersonal ethnic-racial discrimination and tobacco products: The moderating role of critical action.

OBJECTIVE: The present study aimed to understand the role of critical action, sociopolitical participation, an essential form of consciousness in the relationship between interpersonal discrimination and the use of tobacco products. METHOD: The present study was part of a more extensive longitudinal study on students' genetic and environmental experiences. To examine these associations, 164 racially minoritized college students (Mage = 19.86, SD = 0.28) were surveyed for this study. RESULTS: Findings indicated that the relation between interpersonal ethnic-racial discrimination (IERD) and tobacco products was moderated by critical action. Specifically, IERD was associated with greater use of tobacco products when students had low critical consciousness-critical action. The relation between IERD and the use of tobacco products became nonsignificant when students had high critical action. CONCLUSIONS: Critical action was protective in mitigating increased tobacco use in the context of discrimination experiences. Research, clinical, and policy implications are discussed in efforts to reduce tobacco-related disparities among racially minoritized college students. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The impact of the COVID-19 pandemic on alcohol use disorder symptoms: Testing interactions with polygenic risk.

Objective: The purpose of this study was to test whether COVID impact interacts with genetic risk (polygenic risk score/PRS) to predict alcohol use disorder (AUD) symptoms. Method: Participants were n = 455 college students (79.6% female, 51% European Ancestry/EA, 24% African Ancestry/AFR, 25% Americas Ancestry/AMER) from a longitudinal study during the initial stage (March-May 2020) of the pandemic. Path models allowed for the examination of PRS and previously identified COVID-19 impact constructs. Results: There was a main effect of the AUD PRS on AUD symptoms within the EA group (ß: .165, p < .01). Additionally, food/housing insecurity was predictive in the AMER group (ß.295, p < .05), and greater increases in substance use were associated with AUD symptoms for EA (ß:.459, p < .001) and AMER groups (ß:.468, p < .001). Conclusions: Greater food/housing instability and increases in substance use, as well higher scores on PRS are associated with more AUD symptoms for some ancestral groups within this college sample.

Post-traumatic stress disorder and drug use disorder: examination of aetiological models in a Swedish population-based cohort.

Background: There are two primary phenotypic models of comorbidity between post-traumatic stress disorder (PTSD) and drug use disorder (DUD), i.e. self-medication (PTSD precedes and causes DUD) and susceptibility (DUD precedes and causes PTSD). We sought to clarify the longitudinal relationship between PTSD and DUD, while examining sex differences.Method: We used approximately 23 years of longitudinal data from Swedish population registries to conduct two complementary statistical models: Cox proportional hazard models (N ≈ 1.5 million) and a cross-lagged panel model (N ≈ 3.8 million).Results: Cox proportional hazards models, adjusting for cohort and socioeconomic status, found strong evidence for the self-medication hypothesis, as PTSD predicted increased risk for DUD among both women [hazard ratio (HR) = 5.34, 95% confidence interval (CI) 5.18, 5.51] and men (HR = 3.65, 95% CI 3.54, 3.77), and moreover, that the PTSD to DUD association was significantly higher among women (interaction term 0.68, 95% CI 0.65, 0.71). The results of the susceptibility model were significant, but not as strong as the self-medication model. DUD predicted risk for PTSD among both women (HR = 2.43, 95% CI 2.38, 2.50) and men (HR = 2.55, 95% CI 2.50, 2.60), and HR was significantly higher in men (interaction term 1.05, 95% CI 1.02, 1.08). Investigating the pathways simultaneously in the cross-lagged model yielded support for both pathways of risk. The cross-paths instantiating the susceptibility model (0.10-0.22 in females, 0.12-0.19 in males) were mostly larger than those capturing the self-medication model (0.01-0.16 in females, 0.04-0.22 in males).Conclusions: We demonstrate that the relationship between PTSD and DUD is bidirectional, with evidence that future research should prioritize examining specific pathways of risk that may differ between men and women.

Post-traumatic stress disorder (PTSD) and drug use disorder (DUD) are highly comorbid, and few large population-based longitudinal studies have been conducted to better understand why these disorders co-occur at a rate far greater than chance.We used approximately 23 years of longitudinal data from the Swedish National Registries, in a sample of over 1.5 million people, to look at the prospective relationships between PTSD and DUD, and vice versa.We found evidence for bidirectional risk such that having one disorder increased the future risk for the other disorder, although the effect sizes were higher for PTSD's risk on future DUD, and some patterns differed by sex.

Discovery of 95 PTSD loci provides insight into genetic architecture and neurobiology of trauma and stress-related disorders.

Posttraumatic stress disorder (PTSD) genetics are characterized by lower discoverability than most other psychiatric disorders. The contribution to biological understanding from previous genetic studies has thus been limited. We performed a multi-ancestry meta-analysis of genome-wide association studies across 1,222,882 individuals of European ancestry (137,136 cases) and 58,051 admixed individuals with African and Native American ancestry (13,624 cases). We identified 95 genome-wide significant loci (80 novel). Convergent multi-omic approaches identified 43 potential causal genes, broadly classified as neurotransmitter and ion channel synaptic modulators (e.g., GRIA1, GRM8, CACNA1E ), developmental, axon guidance, and transcription factors (e.g., FOXP2, EFNA5, DCC ), synaptic structure and function genes (e.g., PCLO, NCAM1, PDE4B ), and endocrine or immune regulators (e.g., ESR1, TRAF3, TANK ). Additional top genes influence stress, immune, fear, and threat-related processes, previously hypothesized to underlie PTSD neurobiology. These findings strengthen our understanding of neurobiological systems relevant to PTSD pathophysiology, while also opening new areas for investigation.

Genetic associations between alcohol phenotypes and life satisfaction: a genomic structural equation modelling approach.

Alcohol use (i.e., quantity, frequency) and alcohol use disorder (AUD) are common, associated with adverse outcomes, and genetically-influenced. Genome-wide association studies (GWAS) identified genetic loci associated with both. AUD is positively genetically associated with psychopathology, while alcohol use (e.g., drinks per week) is negatively associated or NS related to psychopathology. We wanted to test if these genetic associations extended to life satisfaction, as there is an interest in understanding the associations between psychopathology-related traits and constructs that are not just the absence of psychopathology, but positive outcomes (e.g., well-being variables). Thus, we used Genomic Structural Equation Modeling (gSEM) to analyze summary-level genomic data (i.e., effects of genetic variants on constructs of interest) from large-scale GWAS of European ancestry individuals. Results suggest that the best-fitting model is a Bifactor Model, in which unique alcohol use, unique AUD, and common alcohol factors are extracted. The genetic correlation (rg) between life satisfaction-AUD specific factor was near zero, the rg with the alcohol use specific factor was positive and significant, and the rg with the common alcohol factor was negative and significant. Findings indicate that life satisfaction shares genetic etiology with typical alcohol use and life dissatisfaction shares genetic etiology with heavy alcohol use.

Study protocol for the Mindful Moms Study: A randomized controlled trial evaluating a mindful movement intervention for marginalized pregnant people experiencing depression.

More than 1 in 5 pregnant people in the United States experience depressive symptoms. Although treatments exist, many people remain under- or un-treated due to concerns about stigma, side effects, and costs of medications or psychotherapy, particularly those who are marginalized (defined as those who are minoritized, low-income, or with low-educational attainment). Further, the standard depression treatments do not address social connectedness, which is a potentially modifiable factor involved in depressive symptom etiology. This protocol presents the rationale, design, and status of the two-arm longitudinal parallel group randomized controlled trial - the Mindful Moms Study - which aims to evaluate the effects and mechanisms of a group-based mindful physical activity (yoga) intervention in marginalized pregnant people with depressive symptoms (n = 200) compared to a prenatal education control group. The primary aim is to evaluate effects of group assignment on depressive symptom severity, anxiety, and perceived stress over time from baseline to six weeks postpartum. Secondary aims include understanding the role of social connectedness as a moderator of the effects and to identify genome-wide DNA methylation patterns associated with depressive symptoms and perceived social connectedness at postpartum. A focus on adequate symptom management through non-pharmacologic, accessible therapies that address social connectedness during pregnancy in marginalized women is an urgent clinical and research priority. The successful completion of this study will provide important insights into social connectedness as a mechanism to decrease depressive symptoms in a largely understudied population. Trial registration: NCT04886856.

A summary of the 38th Annual International Society for Traumatic Stress Studies Presidential Panel: How the traumatic stress community can assist individuals affected by the war in Ukraine.

As the premier global traumatic stress society, the International Society for Traumatic Stress Studies (ISTSS) has an important role to play in educating and raising awareness about the consequences of traumatic events, such as the war in Ukraine. On November 12, 2022, during its 38th annual meeting, the ISTSS hosted an invited Presidential Panel, chaired by Ananda Amstadter during her term as ISTSS President, that brought together trauma experts Peter Ventevogel, Marit Sijbrandij, Vitalii Klymchuck, Iryna Frankova, and Angela Nickerson to highlight how traumatic stress professionals can assist individuals affected by the war in Ukraine. The present paper summarizes the key points from the panel and discusses future challenges anticipated for people affected by the war.

Interactions between COVID-19 family home disruptions and relationships predicting college students' mental health over time.

The present study tested whether family home disruptions during the COVID-19 pandemic in the Spring 2020 (Time 1; T1) informed mental health (i.e., posttraumatic stress disorder [PTSD], depressive, and anxiety symptoms) 7 months later in Fall 2020 at T2 and whether family relationship quality moderated relations. Multigroup path analysis models were used to test whether there were significant differences in relations by emerging adults' ethnic-racial backgrounds. Participants were 811 Black, Asian American, Latine, and White emerging adult college students (Mage = 19.95, SD = .33), and the majority (79.6%) who reported their gender identified as cisgender women. Results indicated that across all individuals, T1 family relationship quality moderated relations between T1 family home disruptions and T2 anxiety and depressive symptoms. At lower levels of T1 family relationship quality, family home disruptions predicted greater T2 depressive and anxiety symptoms. At higher levels of T1 family relationship quality, these relations were not significant. Findings highlight that family relationship quality is an important protective factor for diverse emerging adult college students. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A statistical genetic investigation of psychiatric resilience.

Background: Although trauma exposure (TE) is a transdiagnostic risk factor for many psychiatric disorders, not everyone who experiences TE develops a psychiatric disorder. Resilience may explain this heterogeneity; thus, it is critical to understand the etiologic underpinnings of resilience.Objective: The present study sought to examine the genetic underpinnings of psychiatric resilience using genome-wide association studies (GWAS), genome-wide complex trait analysis (GCTA), and polygenic risk score (PRS) analyses.Method: Participants were 6,634 trauma exposed college students attending a diverse, public university in the Mid Atlantic. GWAS and GCTA analyses were conducted, and using GWAS summary statistics from large genetic consortia, PRS analyses examined the shared genetic risk between resilience and various phenotypes.Results: Results demonstrate that nine single-nucleotide polymorphisms (SNPs) met the suggestive of significance threshold, heritability estimates for resilience were non-significant, and that there is genetic overlap between resilience and AD, as well as resilience and PTSD.Conclusion: Mixed findings from the present study suggest additional research to elucidate the etiological underpinnings of resilience, ideally with larger samples less biased by variables such as heterogeneity (i.e. clinical vs. population based) and population stratification. Genetic investigations of resilience have the potential to elucidate the molecular bases of stress-related psychopathology, suggesting new avenues for prevention and intervention efforts.

Resilience may explain the heterogeneity in outcomes following trauma exposure; thus, it is critical to understand the etiologic underpinnings of resilience.The present study sought to examine the genetic underpinnings of psychiatric resilience using genome-wide association studies (GWAS), genome-wide complex trait analysis (GCTA), and polygenic risk score (PRS) analyses.Results demonstrated shared genetic overlap between resilience and Alcohol Dependence, as well as resilience and PTSD.Genetic investigations of resilience have the potential to elucidate the molecular bases of stress-related psychopathology, suggesting new avenues for prevention and intervention efforts.

Testing Phenotypic Models of Posttraumatic Stress Disorder and Alcohol Use Disorder Comorbidity Using Longitudinal Registry Data.

OBJECTIVE: Two predominant phenotypic models of causality exist to explain the high co-occurrence of posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD): the self-medication and susceptibility models. Population-based longitudinal studies that simultaneously examine both models are needed. Thus, the goal of the present study is to test these models using the Swedish National Registries. METHOD: Registries were used to conduct longitudinal Cox proportional hazard models (n ≈ 1.5 million) and cross-lagged panel models (N ≈ 3.8 million) with follow-up periods of ~23 years. RESULTS: Covarying for cohort and socioeconomic status, Cox proportional hazards model results found strong support for the self-medication model. Results showed that PTSD predicted increased risk for AUD among both men (HR = 4.58 [4.42, 4.74]) and women (HR = 4.14 [3.99, 4.30]), significantly more so for men (interaction HR = 1.11 [1.05, 1.16]). Support was also found for the susceptibility model, although the effects were lower in magnitude than those for the self-medication model. AUD increased risk for PTSD among men (HR = 2.53 [2.47, 2.60]) and women (HR = 2.06 [2.01, 2.12]), and significantly more so for men (interaction term HR = 1.23 [1.18, 1.28]). Cross-lagged model results of simultaneously testing both models found support for bidirectionality. The PTSD-to-AUD paths and the AUD-to-PTSD paths were of modest effect for men and women. CONCLUSIONS: The results from both complementary statistical approaches demonstrate that the models of comorbidity are not mutually exclusive. Although the Cox model results evidenced more support for the self-medication pathway, the cross-lagged model results suggest that the prospective relationships between these disorders are nuanced across development.

Resilient phenotypes among bereaved youth: a comparison of trajectory, relative, and cross-domain approaches.

BACKGROUND: Bereavement is a common traumatic event associated with adverse health outcomes across the life course. Despite these risks, not all bereaved individuals experience these negative effects. Limited scientific consensus exists on how to define resilience in individuals who have experienced the death of a loved one. METHODS: Using a sample of N = 3766 youth from the Avon Longitudinal Study of Parents and Children birth cohort, we identified bereavement of a family member between ages 7 and 8.5. We derived and compared three different approaches to assess resilience among bereaved youth. Trajectory-based psychological resilience identified sub-groups with similar psychological symptom profiles between ages 6 and 16 using latent growth mixture models. Relative psychological resilience at age 16 leveraged standardized residuals from a model regressing psychological symptoms on bereavement to determine better-than-expected psychological functioning relative to bereavement status. Relative cross-domain resilience around age 16 was a sum score of the residuals approach applied to eight unique domains of health. Predictive validity of each approach was assessed using depressive symptoms at age 17.5 RESULTS: Overall, N = 877 (23%) youth were bereaved of a family member between ages 7 and 8.5. Using latent growth mixture models, a three-class solution described 84% of bereaved youth with low and stable psychological symptoms over time, 8% with worsening symptoms, and 8% with improving yet elevated symptoms. Each relative resilience score was largely concordant with the trajectory-based approach in identifying individuals as resilient or not, though relative psychological resilience demonstrated a stronger degree of concordance than the cross-domain score. Relative psychological and cross-domain resilience exhibited moderate to low correlation, depending on the domains included (r = 0.14-0.43). For each approach, resilience significantly predicted lower depressive symptoms at age 17.5, highlighting predictive validity of these measures. CONCLUSIONS: Psychological symptom trajectories among bereaved youth aligned with those previously identified among bereaved adults. The residual-based approach to defining resilience exhibited limited utility in the context of bereavement. When identifying risk and resilience after bereavement, researchers and clinicians must address the interplay across psychosocial and physical health domains, as bereaved youth considered resilient from a mental health perspective may benefit from intervention in other domains.

Resilience and alcohol use in adulthood in the United States: A scoping review.

High levels of alcohol use and the development of alcohol use disorder (AUD) are associated with various adverse consequences. Resilience has been proposed as a protective factor against increased alcohol use, though the existing research is limited by inconsistencies in the conceptualization and measurement of resilience. As such, the current scoping review examined 14 studies on individual, trait-level resilience as a protective factor against alcohol use and related consequences in adults over the age of 21 in the United States. Findings from the included studies generally suggest resilience as a protective factor against various outcomes, though methodological limitations should be considered. Although future research in this area should improve upon methodological limitations, the present review suggests clinical implications of resilience as beneficial in prevention and intervention programming for alcohol use outcomes.

Monthly correlates of longitudinal child mental health during the COVID-19 pandemic according to children and caregivers.

Multiple reviews identify the broad, pervasive initial impact of the global COVID-19 pandemic on the mental health of children, who may be particularly vulnerable to long-term psychiatric sequelae of the ongoing pandemic. However, limited longitudinal research examines persistence of, or change in, children's distress or psychiatric symptomatology. From June 2020 through December 2021, we enrolled two cohorts of families of children aged 8-13 from Southwestern Ontario into a staggered baseline, longitudinal design that leveraged multi-informant report (N = 317 families). In each family, one child and one parent/guardian completed a baseline assessment, 6 monthly follow-up assessments, and one final follow-up assessment 9 months post-baseline. At each assessment, the child and parent/guardian completed the CoRonavIruS health Impact Survey and measures of child anxiety, depressive, irritability, and posttraumatic stress syndromes. Children's mental health, indexed by the severity of multiple syndromes, fluctuated over the study period. Elevated local monthly COVID-19 prevalence, hospitalization, and death rates were associated with monthly elevations in children's reported worry about contracting COVID-19 and stress related to stay-at-home orders. In turn, both elevated monthly worry about contracting COVID-19 and stress related to stay-at-home orders were associated with monthly elevations in child- and parent-/guardian-report of children's emotional distress and psychiatric syndromes. This study illustrates the importance of, and informs the potential design of, longitudinal research to track the mental health of children, who may be particularly vulnerable to broad psychosocial sequelae of health crises such as the COVID-19 pandemic.

The longitudinal buffering effects of resilience on alcohol use outcomes.

OBJECTIVE: Traumatic events (TE) are a risk factor for alcohol use disorder (AUD). Resilience may be protective of the effects of TE exposure, but few studies have longitudinally tested the buffering hypothesis. Thus, the present study aimed to fill this gap. METHOD: Participants (N = 6,015) were from a longitudinal investigation into substance use and health outcomes at a large, urban university. Participants completed self-report measures on precollege internalizing symptoms and lifetime trauma load. Resilience was calculated as a quantitative variable. At each of the follow-up assessments, participants reported on past month consumption, AUD symptoms, and new onset TEs. Longitudinal path modeling was used to test interactions. RESULTS: Higher new onset TE load was associated with greater AUD symptoms, and higher consumption at one time-point. Results demonstrate a significant main effect of resilience at Y1S and Y3S, and a significant interaction between resilience and new onset TE at the last time-point, whereby higher levels of new onset TE were associated with higher levels of AUD symptoms at low (ß = .19, p < .001), and average (ß = .20, p = .001) levels of resilience. This effect was attenuated at high levels of resilience (ß = .07, p = .051). No significant main nor interaction effects of resilience on consumption were found. CONCLUSIONS: Findings suggest resilience as an important protective factor in relation to the development of AUD symptoms after exposure to a TE, though perhaps less so in relation to consumption. Findings are consistent with prior work demonstrating that AUD symptoms are more clinically relevant than consumption in this population. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Is pre-college interpersonal trauma associated with cannabis use?

OBJECTIVE: To examine the prevalence and correlates of lifetime cannabis use (i.e., experimental [use 1-5 times] and non-experimental [use ≥ 6 times]) in relation to interpersonal trauma (IPT) above and beyond relevant covariates. PARTICIPANTS: A large (n = 9,889) representative sample of college students at an urban university in the southeastern part of the United States. METHODS: Participants were 4 cohorts of first-year college students who completed measures of demographics, cannabis, alcohol, nicotine, and IPT. Associations were estimated using multinomial logistic regressions. RESULTS: The prevalence of lifetime cannabis use was 28.1% and 17.4% for non-experimental and experimental cannabis use, respectively. IPT was significantly associated with experimental and non-experimental cannabis use above and beyond effects of sex, race, cohort, alcohol, and nicotine. CONCLUSIONS: Results show that cannabis use is prevalent among college students and is associated with IPT above and beyond associations with sex, race, and other substance use.

A longitudinal mediational investigation of risk pathways among cannabis use, interpersonal trauma exposure, and trauma-related distress.

OBJECTIVE: College students are at high risk for cannabis use, interpersonal trauma (IPT) exposure, and trauma-related distress (TRD). Two phenotypic etiologic models posited to explain associations between cannabis use and trauma-related phenotypes are the self-medication (trauma/TRD → cannabis use) and high-risk (cannabis use → trauma/TRD) hypotheses. The primary objective of the present study was to investigate direct and indirect associations among cannabis use, IPT exposure, and TRD above and beyond established covariates. METHOD: The current study used data from the first assessment (i.e., baseline survey at Year 1 Fall) and two follow-up assessments (i.e., Year 1 Spring and Year 2 Spring) from an ongoing longitudinal study on college behavioral health. Participants were 4 cohorts of college students (n = 9,889) who completed measures of demographics, substance use, IPT, and TRD. Indirect effects of IPT on cannabis through TRD (i.e., self-medication) and cannabis on TRD through IPT (i.e., high-risk), including tests of covariate effects (e.g., gender, age, race, cohort, alcohol, nicotine), were simultaneously estimated using a longitudinal mediation modeling framework. RESULTS: Results suggest that more IPT exposure increases risk for TRD and subsequent nonexperimental (use 6+ times) cannabis use, and that experimental (use 1-5 times) and nonexperimental cannabis use increases risk for IPT exposure and subsequent TRD. CONCLUSIONS: Both the self-medication and high-risk hypotheses were supported. Findings support a bidirectional causal relationship between cannabis use and trauma-related phenotypes. Additionally, results highlight areas for colleges to intervene among students to help reduce cannabis use and create a safer environment. (PsycInfo Database Record (c) 2023 APA, all rights reserved).