Burden of cannabis use and disorder in the U.S. veteran population: Psychiatric comorbidity, suicidality, and service utilization

Herbal Cannabis and Depression: A Review of Findings Published over the Last Three Years

Public perception contrasts scientific findings on the depression-related effects of cannabis. However, earlier studies were performed when cannabis was predominantly illegal, its production was mostly uncontrolled, and the idea of medical cannabis was incipient only. We hypothesized that recent changes in attitudes and legislations may have favorably affected research. In addition, publication bias against cannabis may have also decreased. To investigate this hypothesis, we conducted a review of research studies published over the last three years. We found 156 relevant research articles. In most cross-sectional studies, depression was higher in those who consumed cannabis than in those who did not. An increase in cannabis consumption was typically followed by an increase in depression, whereas withdrawal from cannabis ameliorated depression in most cases. Although medical cannabis reduced depression in most studies, none of these were placebo-controlled. In clinical studies published in the same period, the placebo also ameliorated depression and, in addition, the average effect size of the placebo was larger than the average effect size of medical cannabis. We also investigated the plausibility of the antidepressant effects of cannabis by reviewing molecular and pharmacological studies. Taken together, the reviewed findings do not support the antidepressant effects of herbal cannabis.

Prevalence and Correlates of Cannabis Use among U.S. Veterans during the Second Wave of the COVID-19 Pandemic

INTRODUCTION

Military veterans are at increased risk of substance use disorders. Limited research is available about veterans' cannabis use (CU) during the coronavirus disease 2019 (COVID-19) pandemic. This study estimated the prevalence of past 30-day CU, investigated individual-level correlates of past 30-day CU, and evaluated the reasons (medical, recreational, or both) of past 30-day CU among U.S. Veterans during the second wave of the COVID-19 pandemic.

MATERIALS AND METHODS

We used population-based, cross-sectional data from the 2021 Behavioral Risk Factor Surveillance System Survey Marijuana Use model. The sample included nationally representative military veterans aged 18+ years (n = 11,167). The outcome was past 30-day CU. Individual-level demographic, socioeconomic, behavioral, and clinical correlates were examined. Analyses were weighted to account for the survey's complex design with results generalizable to nearly 2.9 million veterans. We conducted weighted descriptive statistics, prevalence estimates, and multivariable logistic regression analyses.

RESULTS

Out of 2.9 million veterans, 11.1% self-reported as non-Hispanic Black, 3.7% Hispanic, and 79.1% non-Hispanic White; 88.5% were men, and 72.8% were aged 50+ years. About 14.6% were current tobacco smokers, 4.7% were current e-cigarette users, 12.5% were binge alcohol drinkers, and 43.4% had three or more comorbid conditions. Overall, 8.5% reported CU in the past 30 days, of which 30.4% used it for medical reasons and 25.8% used it for nonmedical reasons. The prevalence of past 30-day CU decreased with age, education, and income level. Compared to their counterparts, the odds of past 30-day CU were greater among men, those living in urban areas, those with frequent mental distress, infrequent physical distress, and those who had at least one comorbid condition. Non-Hispanic Black veterans had 89% increased odds of past 30-day CU (adjusted odds ratio [AOR] =1.89, 95% confidence interval [CI], 1.19-3.0) compared with non-Hispanic White veterans. Current tobacco smokers had 3.54 (95% CI, 2.40-5.24) and former smokers had 1.78 (95% CI, 1.28-2.47) times higher odds of reporting past 30-day CU than never smokers. Current e-cigarette use (AOR = 3.37, 95% CI, 2.20-5.16) and binge drinking (AOR = 3.18, 95% CI, 2.29-4.41) were also statistically significantly associated with increased odds of past 30-day CU compared to no e-cigarette use and no binge drinking.

CONCLUSIONS

CU is prevalent among veterans, and certain subgroups are at higher risk of CU. Thus, identifying high-risk subgroups of veterans and adequately educating them about CU's benefits, risks, and safety is crucial.

Genome-wide DNA methylation analysis of cannabis use disorder in a veteran cohort enriched for posttraumatic stress disorder

Cannabis use has been increasing over the past decade, not only in the general US population, but particularly among military veterans. With this rise in use has come a concomitant increase in cannabis use disorder (CUD) among veterans. Here, we performed an epigenome-wide association study for lifetime CUD in an Iraq/Afghanistan era veteran cohort enriched for posttraumatic stress disorder (PTSD) comprising 2,310 total subjects (1,109 non-Hispanic black and 1,201 non-Hispanic white). We also investigated CUD interactions with current PTSD status and examined potential indirect effects of DNA methylation (DNAm) on the relationship between CUD and psychiatric diagnoses. Four CpGs were associated with lifetime CUD, even after controlling for the effects of current smoking (AHRR cg05575921, LINC00299 cg23079012, VWA7 cg22112841, and FAM70A cg08760398). Importantly, cg05575921, a CpG strongly linked to smoking, remained associated with lifetime CUD even when restricting the analysis to veterans who reported never smoking cigarettes. Moreover, CUD interacted with current PTSD to affect cg05575921 and cg23079012 such that those with both CUD and PTSD displayed significantly lower DNAm compared to the other groups. Finally, we provide preliminary evidence that AHRR cg05575921 helps explain the association between CUD and any psychiatric diagnoses, specifically mood disorders.

Unhealthy behaviors associated with mental health disorders: a systematic comparative review of diet quality, sedentary behavior, and cannabis and tobacco use

Background

There are well-established literatures documenting the associations between mental disorders and unhealthy behaviors such as poor diet quality, sedentary behavior, and cannabis and tobacco use. Few studies have attempted to understand the respective findings in light of each other, however.

Objective

The purpose of this review was to assemble comparable data for each behavior-disorder association and assess the associations in terms of their overall strength. The review aimed to include a representative, but not exhaustive, range of studies that would allow for explorative comparisons.

Methods

Eligible studies were identified via Pubmed searches and citation searching, restricted to publications no older than 2015 written in English. To obtain comparable data, only studies that reported findings as odds ratios were included, and risk of bias related to study samples, behavioral measurement disparities, and control variables was assessed via sensitivity analyses. Findings for each disorder were compared on the basis of different measures of central tendency.

Results

From 3,682 records, 294 studies were included. The review found evidence of associations between each of the four unhealthy behaviors and psychosis, depression, anxiety, bipolar disorder, attention-deficit/hyperactivity disorder (ADHD), and post-traumatic stress disorder (PTSD), while personality disorder was only investigated in relation to cannabis and tobacco use. In overall comparison, the associations were generally of similar strength, and only the association between cannabis use and personality disorder was exceptional in terms of being significantly stronger than its counterparts across disorders and across behaviors. Analyses of bias risk identified some influence from behavioral measurement disparities and lack of adequate statistical control, but findings were generally robust across a range of sensitivity analyses.

Conclusion

This explorative and comparative review found that poor diet quality, sedentary behavior, and cannabis and tobacco use are about equally strongly associated with a range of different mental disorders. Given the general nature of these associations, we should probably understand them to reflect a general and shared etiology. However, the findings in this review should be regarded as tentative until confirmed by more comprehensive investigations.

Cannabis Use Among U.S. Military Veterans Following Residential Substance Use Disorder Treatment

INTRODUCTION

Use rates of cannabis, a substance associated with a host of comorbid physical and mental health concerns, continue to rise for military veterans. Despite this prevalence, descriptive patterns of use among veterans and research on treatment factors that predict cannabis outcomes are lacking. This study aimed to conduct a descriptive profile of veterans who endorse cannabis use, compare veterans endorsing cannabis use to those who do not endorse use, and investigate what factors (other substance use, psychiatric symptoms, and treatment outcomes) predicted return to cannabis use following residential treatment.

MATERIALS AND METHODS

The study was a secondary data analysis of a longitudinal sample of U.S. military veterans (N = 200, 193 males, Mage = 50.14, SD = 9) participating in residential substance use disorder treatment through a Veterans Affairs medical center. Interview, survey, and electronic health data were collected over 12 months. Analyses included descriptive and frequency statistics to identify patterns in cannabis use behaviors and motives, independent t-tests to examine differences between the cannabis-using group and non-using group, and a series of univariate logistic regressions to examine potential predictors for cannabis use after treatment discharge.

RESULTS

Lifetime cannabis use was common among veterans (77.5%), and 29.5% reported use during the study. On average, veterans had made one quit attempt before treatment entry. Veterans who endorsed cannabis use consumed more alcohol in the past 30 days at baseline and reported less impulse control and less confidence in maintaining abstinence at discharge. Length of stay in the residential program and no diagnosis of Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV cannabis use disorder criteria predicted post-treatment cannabis use such that veterans who remained in the program longer were more likely to abstain from cannabis use following treatment, and those who did not meet DSM-IV cannabis use disorder criteria were more likely to use following treatment.

CONCLUSIONS

Identification of relevant risk factors and treatment processes, such as impulse control, confidence in treatment, and length of stay in treatment, provides practical recommendations for future intervention efforts. This study calls for further examination of cannabis use outcomes among veterans, particularly those participating in substance use treatment.

Mental and Physical Health Conditions Among U.S. Veterans with Cannabis Use and Cannabis Use Disorders

Purpose of Review

Veterans are a large population that is disproportionately affected by various physical and mental health conditions. The primary aim of this review is to provide a concise overview of recent literature on the prevalence of cannabis use and cannabis use disorder (CUD) among US Veterans, and associations with mental and physical health conditions. We also addressed gaps in the literature by investigating associations between CUD and mental and physical health conditions in 2019 data from the Veterans Health Administration (VHA; N=5,657,277).

Recent Findings

In total, 25 studies were reviewed. In 2019, the prevalence of Veteran cannabis use ranged from 11.9%-18.7%. Cannabis use and CUD were associated with bipolar disorders, psychotic disorders, suicidality, pain conditions, and other substance use, but less consistently associated with depressive disorders, anxiety disorders, and posttraumatic stress disorder. Analyses of 2019 VHA data indicated that CUD was strongly associated with a broad array of physical and mental health conditions and mortality.

Summary

Cannabis use and CUD are prevalent and highly comorbid with other conditions among US Veterans. Harm reduction methods tailored to these populations are needed.

Cannabis use among U.S. military veterans with subthreshold or threshold posttraumatic stress disorder: Psychiatric comorbidities, functioning, and strategies for coping with posttraumatic stress symptoms

Cannabis use is common among individuals with posttraumatic stress disorder (PTSD) symptoms, but its impact on psychiatric symptoms and functioning in this population is unclear. To clarify the clinical and functional correlates of cannabis use in individuals with PTSD symptoms, we analyzed data from the 2019-2020 National Health and Resilience in Veterans Study, a nationally representative survey of U.S. military veterans. Participants with current subthreshold or full PTSD (N = 608) reported on their past-6-month cannabis use and current psychiatric symptoms, functioning, treatment utilization, and PTSD symptom management strategies. Veterans with subthreshold/full PTSD who used cannabis more than weekly were more likely to screen positive for co-occurring depression, anxiety, and suicidal ideation than those who did not use cannabis, ORs = 3.4-3.8, or used cannabis less than weekly, ORs = 2.7-3.7. Veterans who used cannabis more than weekly also scored lower in cognitive functioning than veterans with no use, d = 0.25, or infrequent use, d = 0.71, and were substantially more likely to endorse avoidance coping strategies, ORs = 8.2-12.2, including substance use, OR = 4.4, and behavioral disengagement, ORs = 2.7-9.1, to manage PTSD symptoms. Despite more psychiatric and functional problems, veterans with frequent cannabis use were not more likely to engage in mental health treatment, ORs = 0.87-0.99. The results suggest enhanced cannabis use screening, interventions targeting risky use, and strategies promoting treatment engagement may help ameliorate more severe clinical presentations associated with frequent cannabis use among veterans with subthreshold/full PTSD.

Craving and emotional responses to trauma and cannabis cues in trauma-exposed cannabis users: Influence of PTSD symptom severity

Conditioned craving to trauma cues and avoidance learning have both been implicated in the high concurrence of trauma-related distress and substance misuse. Using a cue-exposure paradigm involving personalized trauma, cannabis, and neutral cues, we examined if conditioned craving and/or elevated negative affect to trauma cues are mechanisms linking PTSD and cannabis use disorder. Fifty-one trauma-exposed cannabis users were randomly presented the three cue types. Craving and emotional responses were evaluated after each cue using the Marijuana Craving Questionnaire-Short Form (Heishman et al., 2001) and the Positive and Negative Affect Schedule (Watson et al., 1988). Relief cannabis craving (compulsivity and emotionality) was significantly higher after trauma than cannabis and neutral cues (p's < 0.001) and was also higher among those with more severe PTSD symptoms (p's < 0.05). The relationship between PTSD symptom severity and cannabis craving was stronger after trauma than cannabis cues for the compulsivity component of craving (p < .05). Relief craving was also higher after the cannabis cue than after the neutral cue (expectancy and purposefulness; p < .001). Negative affect was significantly higher: after trauma than cannabis and neutral cues (p's < 0.001); and among those with more severe PTSD symptoms (p < . 005). Positive affect was significantly lower after trauma than cannabis cues (p < .05). Trauma cue exposure might promote cannabis misuse through conditioned craving as well as the desire to relieve negative affect. Conditioned cannabis craving involving an uncontrollable compulsion to use cannabis in response to trauma reminders appears particularly likely among cannabis users with more severe PTSD symptoms.

Prevalence of cannabis use, disorder, and medical card possession in U.S. military veterans: Results from the 2019-2020 National Health and Resilience in Veterans Study

More than half of U.S. states legalized medical or recreational sale and possession of cannabis since the prevalence of cannabis use was last estimated among U.S. military veterans in 2014. To provide updated estimates of the prevalence and correlates of cannabis use, cannabis use disorder (CUD), and medical cannabis card possession in this population, data were analyzed from the 2019-2020 National Health and Resilience in Veterans Study, a nationally representative survey of 4,069 veterans ages 22-99 years who reported on their past-6-month cannabis use, CUD symptoms, and possession of a medical cannabis card. An estimated 11.9% [95% confidence interval (CI) = 10.9-12.9%)] of veterans reported using cannabis, 2.7% (95% CI = 2.3-3.3%) screened positive for CUD, and 1.5% (95% CI = 1.2-2.0%) reported possessing a medical card. Prevalence of cannabis use, CUD, and card possession were higher among younger veterans (use: 20.2%, CUD: 5.6%, card: 2.1%) and those with psychiatric conditions (use: 24.0%-30.0%, CUD: 8.9%-13.0%, card: 3.1%-4.0%). Younger age, alcohol use disorder, and childhood adversity explained a large proportion of variance in cannabis use and CUD, and depression was independently associated with CUD (odds ratio [OR] = 2.76). Physical disability (OR = 3.59), combat veteran status (OR = 2.84), and non-Hispanic black (OR = 0.23) relative to white race/ethnicity most strongly predicted using cannabis with a medical card. The estimated prevalence of cannabis use in veterans-nearly 12%-is higher than the most recently reported estimate (9% in 2014). Veteran cannabis use may be increasing and is particularly prevalent among veterans with psychiatric conditions.

Moral injury and suicidal behavior among US combat veterans: Results from the 2019-2020 National Health and Resilience in Veterans Study

BACKGROUND

Recent research suggests that exposure to potentially morally injurious experiences (PMIEs) may be associated with increased risk for suicidal behavior among US combat veterans, but population-based data on these associations are scarce. This study examined the association between PMIEs with current suicidal ideation (SI), lifetime suicide plans (SP), and suicide attempts (SA) in a contemporary, nationally representative sample of combat veterans.

METHODS

Data were analyzed from the 2019-2020 National Health and Resilience in Veterans Study, which surveyed a nationally representative sample of US combat veterans (n = 1321). PMIEs were assessed using the Moral Injury Events Scale (MIES). Multivariable logistic regression analyses were conducted to examine associations between MIES total scores and specific types of PMIEs with suicidal behavior.

RESULTS

Thirty-six point three percent of veterans reported at least one PMIE. Perceived transgressions by self, others, and betrayal were associated with SI, SP, and SA (odds ratios [ORs] = 1.21-1.27, all p s < .05), after adjusting for sociodemographic, trauma, and psychiatric characteristics. MIES total scores were significantly, albeit weakly, associated with SP (OR = 1.03, p < .01), but not SI/SA. Depression, posttraumatic stress disorder (PTSD), and age emerged as the strongest correlates of SI/SP/SA (14.9%-38.1% of explained variance), while PMIEs accounted for a comparatively modest amount of variance (3.3%-8.9%).

CONCLUSIONS

Reports of potentially morally injurious experiences are prevalent among US combat veterans, and associated with increased risk for suicidal behavior, above and beyond severity of combat exposure, PTSD, and depression. Implications for clinical practice and future research are discussed, including the need for methodological advancements in the measurement of moral injury.

Comparative associations of problematic alcohol and cannabis use with suicidal behavior in U.S. military veterans: A population-based study

Alcohol use disorder (AUD) and cannabis use disorder (CUD) are each associated with increased suicidal behavior, but it is unclear how their comorbidity relates to suicide risk. Understanding these associations in U.S. military veterans is especially important, given their heightened risk for suicide, high prevalence of AUD, and increasing access to cannabis. We compared associations of probable AUD, CUD, and AUD/CUD with suicide ideation, plan(s), and attempt(s) in a nationally representative sample of 4,069 veterans surveyed in 2019-2020 as part of the National Health and Resilience in Veterans Study. Among veterans who screened positive for current AUD, 8.7% also screened positive for current CUD. Among veterans who screened positive for current CUD, 33.3% screened positive for current AUD. Current and lifetime positive screens for AUD, CUD, and AUD/CUD were each strongly and independently associated with past-year suicide ideation and lifetime suicide ideation, plan(s), and attempt(s) [odds ratios (ORs) = 1.6-8.7]. Relative to veterans who screened positive for AUD only, veterans who screened positive for AUD/CUD and CUD only had higher odds of past-year suicide ideation (AUD/CUD: OR = 3.3; CUD only: OR = 2.4), lifetime suicide ideation (AUD/CUD: OR = 1.9; CUD only: OR = 2.6) and lifetime suicide plan(s) (AUD/CUD: OR = 1.7; CUD only: OR = 6.1). Collectively, findings suggest that screening positive for CUD might be an especially strong indicator of suicide ideation and planning in veterans with and without AUD, independent of sociodemographic, military, trauma, and other psychiatric factors. These findings underscore the importance of routine screening for CUD in suicide prevention efforts, especially as cannabis becomes more widely available.