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BackgroundPosttraumatic stress disorder (PTSD) is the most highly co-occurring psychiatric disorder among veterans with cannabis use disorder (CUD). Despite some evidence that cannabis use prospectively exacerbates the course of PTSD, which in turn increases the risk for CUD, the causal nature of the relationship between cannabis and psychiatric comorbidity is debated. The longitudinal relationship between PTSD diagnosis and traumatic intrusion symptoms with cannabis use and CUD was examined using cross-lagged panel model (CLPM) analysis.MethodsProspective data from a longitudinal observational study of 361 veterans deployed post-9/11/2001 included PTSD and CUD diagnoses, cannabis use, and PTSD-related traumatic intrusion symptoms from the Inventory of Depression and Anxiety Symptoms.ResultsA random intercept CLPM analysis that leveraged three waves (baseline, 6 months and 12 months) of cannabis use and PTSD-related intrusion symptoms to account for between-person differences found that baseline cannabis use was significantly positively associated with 6-month intrusion symptoms; the converse association was significant but reduced in magnitude (baseline use to 6-month intrusions: β = 0.46, 95% CI 0.155-0.765; baseline intrusions to 6-month use: β = 0.22, 95% CI -0.003 to 0.444). Results from the two-wave CLPM reveal a significant effect from baseline PTSD to 12-month CUD (β = 0.15, 95% CI 0.028-0.272) but not from baseline CUD to 12-month PTSD (β = 0.12, 95% CI -0.022 to 0.262).ConclusionsStrong prospective associations capturing within-person changes suggest that cannabis use is linked with greater severity of trauma-related intrusion symptoms over time. A strong person-level directional association between PTSD and CUD was evident. Findings have significant clinical implications for the long-term effects of cannabis use among individuals with PTSD.

Objective: Attention-deficit/hyperactivity disorder (ADHD) is linked prospectively to cannabis; however, no study has examined mechanisms underlying this comorbidity. We examined 5 cannabis motives (i.e., coping with negative affect, sleep, social anxiety, perceived low risk of cannabis, and altered perception) as mediators of the prospective ADHD-cannabis relation. Method: Veterans reporting lifetime cannabis use (N = 361; 93% male; 80% White) completed three semiannual assessments. Prospective mediation models using structural equation modeling analyzed the indirect effects of baseline ADHD symptoms on 12-month cannabis use and problems via each motive at 6 months. Zero-inflated negative binomial models were employed for both manifest outcomes and ADHD symptoms and motives were each modeled as 1-factor latent variables. Results: Sleep motives was a robust mediator for cannabis use frequency in single mediator models and was marginally significant when examined simultaneously with other motives after accounting for baseline cannabis use, demographics, other substance use, and other psychopathology. Coping with negative affect was the only significant mediator of ADHD symptoms and subsequent cannabis problem severity. Conclusion: Among veterans with ADHD symptoms, sleep disturbance is a salient motive for cannabis use, whereas coping with negative affect is a proximal predictor of cannabis problems. Findings support addressing sleep disturbance in adults with ADHD symptoms and converge with extant literature demonstrating robust associations between coping motives and substance use problems. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

There is a high comorbidity between symptoms of depression and cannabis and alcohol use in civilian and veteran populations. Prospective studies attempting to clarify the directionality of these comorbidities have yielded mixed results. Further, the relations between these constructs and impulsive personality, particularly negative urgency (NU, the tendency to act rashly when experiencing emotional distress) warrants further attention, as NU relates to symptoms of depression and alcohol and cannabis use. Importantly, NU partially accounts for the association between symptoms of depression and cannabis and alcohol problems in cross-sectional studies. This study examined alternative theories of directionality in order to better understand the longitudinal associations between symptoms of depression, NU, and cannabis or alcohol use. Three semiannual waves of data (baseline, 6-month, and 12-month) were collected in parallel assessments from a sample of Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn veterans (N = 361). Autoregressive cross-lagged panel models were used to test four alternative theory-driven models about the longitudinal associations between the interaction of symptoms of depression and NU and cannabis or alcohol use. Models revealed unique direction of effects specific to each substance, such that the interaction between symptoms of depression and NU at 6 months postbaseline predicted more alcohol use at 12 months postbaseline, whereas more cannabis use at 6 months postbaseline predicted more severe symptoms of depression at 12 months postbaseline. Results suggests alternate directions of effect for cannabis and alcohol use. Future research should examine these patterns over wider assessment periods in order to see more variability and change over time. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Although substance use is considered normative in college, continued examination of factors associated with problematic use is merited. This study identified latent substance user classes and examined their relations with sex, race/ethnicity, impulsivity-like facets, and substance use outcomes among 702 undergraduate students. Non-Alcohol Abstaining Users (NAA), Minimal Users (MU), and Polysubstance Users (PSU) emerged from latent class analysis. Variable-centered analyses indicated that substance user classes did not differ by sex. Students in the Asian and Other groups were at greater odds of being in the MU class than either NAA or PSU class, compared to White students. Differential patterns of impulsigenic trait levels emerged across latent classes. The present study highlights the utility of integrating person- and variable-centered approaches in studying heterogeneous substance use behaviors among college students. College PSU are particularly at risk for problematic outcomes, thus warranting preventive intervention that may target impulsigenic traits or polysubstance use.

Objective: Cannabis demand (i.e., relative value), assessed cross-sectionally via a hypothetical marijuana purchase task (MPT), has been associated with use, problems, and dependence symptoms, among others. However, limited work exists on the prospective stability of the MPT. Furthermore, cannabis demand among veterans endorsing cannabis use, and the prospective cyclical relationship between demand and use over time, have yet to be investigated. Method: Two waves of data from a veteran sample (N = 133) reporting current (past 6-month) cannabis use were analyzed to assess stability in cannabis demand over 6 months. Autoregressive cross-lagged panel models (CLPMs) assessed the longitudinal associations between demand indices (i.e., intensity, Omax, Pmax, breakpoint) and cannabis use. Results: Baseline cannabis use predicted greater intensity (β = .32, p < .001), Omax (β = .37, p < .001), breakpoint (β = .28, p < .001), and Pmax (β = .21, p = .017) at 6 months. Conversely, baseline intensity (β = .14, p = .028), breakpoint (β = .12, p = .038), and Pmax (β = .12, p = .043), but not Omax, predicted greater use at 6 months. Only intensity demonstrated acceptable prospective reliability. Conclusions: Cannabis demand demonstrated stability over 6 months in CLPM models, varying along with natural changes in cannabis use. Importantly, intensity, Pmax, and breakpoint displayed bidirectional predictive associations with cannabis use, and the prospective pathway from use to demand was consistently stronger. Test-retest reliability ranged from good to poor across indices. Findings highlight the value of assessing cannabis demand longitudinally, particularly among clinical samples, to determine how demand fluctuates in response to experimental manipulation, intervention, and treatment. [ABSTRACT FROM AUTHOR]

Objective: Co-use of alcohol and cannabis has been associated with more total negative consequences than single-substance use, but results have been mixed depending on whether the single substance was alcohol or cannabis. The present study used within-person analyses to examine whether co-use increased the risk for experiencing specific acute negative consequences. Method: College students who were co-users of alcohol and cannabis (N = 341; M age = 19.8 years; 51.3% female; 74.8% White) completed 56 days of five daily surveys across two bursts. We used generalized linear mixed effects models to examine the effects of type of substance use day on specific negative consequences, controlling for consumption and covariates. Results: Relative to both alcohol-only and co-use days, cannabis-only days were associated with decreased likelihood of experiencing hangover, blackout, nausea/vomiting, injury, rude/aggressive behavior, and unwanted sex. Relative to alcohol-only days, cannabis-only and co-use days were associated with an increased likelihood of driving high/drunk. Finally, there was an increased likelihood of hangovers on alcohol-only days compared with co-use days. Conclusions: Days with different types of substance use differed in specific consequences. Most of the negative co-use consequences investigated here appear to be driven by alcohol consumption rather than cannabis use. The results also indicated that these young adults were more likely to endorse driving under the influence of cannabis than alcohol. Interventions for co-use should target alcohol consumption to reduce negative consequences such as blackout, injury, rude/aggressive behavior, and unwanted sex and highlight the dangers of driving under the influence of cannabis. [ABSTRACT FROM AUTHOR]