Evaluation of delay discounting as a transdiagnostic research domain criteria indicator in 1388 general community adults.

BACKGROUND: The Research Domain Criteria (RDoC) approach proposes a novel psychiatric nosology using transdiagnostic dimensional mechanistic constructs. One candidate RDoC indicator is delay discounting (DD), a behavioral economic measure of impulsivity, based predominantly on studies examining DD and individual conditions. The current study sought to evaluate the transdiagnostic significance of DD in relation to several psychiatric conditions concurrently. METHODS: Participants were 1388 community adults (18-65) who completed an in-person assessment, including measures of DD, substance use, depression, anxiety, posttraumatic stress disorder, and attention-deficit hyperactivity disorder (ADHD). Relations between DD and psychopathology were examined with three strategies: first, examining differences by individual condition using clinical cut-offs; second, examining DD in relation to latent psychopathology variables via principal components analysis (PCA); and third, examining DD and all psychopathology simultaneously via structural equation modeling (SEM). RESULTS: Individual analyses revealed elevations in DD were present in participants screening positive for multiple substance use disorders (tobacco, cannabis, and drug use disorder), ADHD, major depressive disorder (MDD), and an anxiety disorder (ps < 0.05-0.001). The PCA produced two latent components (substance involvement v. the other mental health indicators) and DD was significantly associated with both (ps < 0.001). In the SEM, unique significant positive associations were observed between the DD latent variable and tobacco, cannabis, and MDD (ps < 0.05-0.001). CONCLUSIONS: These results provide some support for DD as a transdiagnostic indicator, but also suggest that studies of individual syndromes may include confounding via comorbidities. Further systematic investigation of DD as an RDoC indicator is warranted.

Getting high to cope with COVID-19: Modelling the associations between cannabis demand, coping motives, and cannabis use and problems.

During the COVID-19 pandemic, people may use substances like cannabis for enhancement or coping purposes. Behavioral economic demand for a substance is a key determinant of its use and misuse and can be measured via hypothetical purchase tasks. Previous research suggests that motivations to use a substance play a mediational role between elevated substance demand and problems, but comparable mechanistic research has yet to be done in the COVID-19 context and on the effects of cannabis demand on cannabis use patterns. Participants (n = 137) were recruited via the online crowdsourcing platform Prolific. Participants completed measures of cannabis use and problems, motivations for cannabis use, and the Marijuana Purchase Task. Two indices of demand, Persistence (i.e., sensitivity to increasing cost of cannabis) and Amplitude (i.e., consumption of cannabis at unrestricted cost), were related to increased cannabis problems via the use motive of coping during the COVID-19 pandemic. This model did not support the mediational role of enhancement motives. Those with increased cannabis demand who tend to use cannabis to cope are at increased risk of experiencing negative cannabis-related consequences during the COVID-19 pandemic.

Consistent evidence of indirect effects of impulsive delay discounting and negative urgency between childhood adversity and adult substance use in two samples.

RATIONALE: Exposure to adverse life experiences (ACEs) is robustly associated with problematic alcohol and other drug use. In addition, both ACEs and substance use have been independently associated with impulsivity. OBJECTIVE: To examine whether impulsivity is implicated in the link between ACE and adult substance use in two samples. METHODS: The primary sample was a cohort of community adults (N = 1431) who completed a one-time in-person assessment. A second sample was crowdsourced using Amazon Mechanical Turk (N = 3021). All participants were assessed for ACEs using the Adverse Childhood Experience Questionnaire and for current alcohol and other drug use. Given its multidimensional nature, impulsivity was assessed using the UPPS-P measure of impulsive personality traits, Go/NoGo (GNG) task (in-person community adult sample only), and delay discounting (Monetary Choice Questionnaire [MCQ] in the community adults and Effective Delay-50 [ED50] in the crowdsourced sample. Structural equation modeling was used to examine the hypothesized indirect effects for the measures of impulsivity between ACEs and substance use. RESULTS: In the community adults, significant indirect effects were observed from ACEs to substance use via UPPS-Negative Urgency (ß = 0.07, SE = 0.02, 95% CI [0.04, 0.10]), and the MCQ (ß = 0.02 SE = .01, 95% CI [0.01, 0.03]). In the crowdsourced sample, significant indirect effects were observed from ACEs to substance use via UPPS-Negative Urgency (ß = 0.05, SE = .01, 95% CI [0.04, 0.07]), UPPS-Premeditation (ß = 0.04, SE = .01, 95% CI [0.02, 0.05), and the ED50 (ß = 0.02, SE = .01; 95% CI [0.01, 0.03]). CONCLUSION: These findings provide consistent evidence that decrements in regulation of negative emotions and overvaluation of immediate rewards indirectly link ACE and substance use. These robust cross-sectional findings support the need for elucidating the underlying neural substrates implicated and for longitudinal evaluations.

Patterns of substance use among adolescents: A systematic review.

PURPOSE: This review characterizes empirically derived patterns of multiple (multi-) substance use among adolescents. A secondary objective was to examine the extent to which mental health symptomatology was included in the empirical analyses examining substance use patterns. METHODS: Eligible studies included those that used cluster-based approaches, included the assessment of at least two different substances, and were based on study samples with mean ages between 11 and 18 years. 4665 records were screened including 461 studies for full-text screening. RESULTS: 70 studies were included with common clusters being: low use, single or dual substance use, moderate general multi-use, and high multi-use. The most common patterns of single or multi-substance use were: alcohol only, alcohol with cannabis and/or tobacco, and use of alcohol, tobacco, and cannabis with and without other drugs. Lower socioeconomic status, older age, and male gender were consistent predictors of multi-use clusters. Only 37 % of studies compared differences in levels of mental health across clusters with symptoms consistently associated with a greater likelihood of multi-use. Only 29 % of studies included mental health indicators in cluster-based analyses, with over half identifying distinct mental health and substance use clusters. Fit indices in cluster analyses and measurement properties of substance use were heterogeneous and inconsistently reported across studies. CONCLUSIONS: Distinct patterns of substance use were derived but methodological differences prevented direct comparison and reduced capacity to generalize across studies. There is a need to establish standardized methodological approaches to identify robust patterns of substance use to enhance etiological, prognostic, and intervention research.

Steep discounting of delayed monetary and food rewards in obesity: a meta-analysis.

BACKGROUND: An increasing number of studies have investigated delay discounting (DD) in relation to obesity, but with mixed findings. This meta-analysis synthesized the literature on the relationship between monetary and food DD and obesity, with three objectives: (1) to characterize the relationship between DD and obesity in both case-control comparisons and continuous designs; (2) to examine potential moderators, including case-control v. continuous design, money v. food rewards, sample sex distribution, and sample age (18 years); and (3) to evaluate publication bias. METHOD: From 134 candidate articles, 39 independent investigations yielded 29 case-control and 30 continuous comparisons (total n = 10 278). Random-effects meta-analysis was conducted using Cohen's d as the effect size. Publication bias was evaluated using fail-safe N, Begg-Mazumdar and Egger tests, meta-regression of publication year and effect size, and imputation of missing studies. RESULTS: The primary analysis revealed a medium effect size across studies that was highly statistically significant (d = 0.43, p < 10-14). None of the moderators examined yielded statistically significant differences, although notably larger effect sizes were found for studies with case-control designs, food rewards and child/adolescent samples. Limited evidence of publication bias was present, although the Begg-Mazumdar test and meta-regression suggested a slightly diminishing effect size over time. CONCLUSIONS: Steep DD of food and money appears to be a robust feature of obesity that is relatively consistent across the DD assessment methodologies and study designs examined. These findings are discussed in the context of research on DD in drug addiction, the neural bases of DD in obesity, and potential clinical applications.