Estimation and inference for the mediation effect in a time-varying mediation model

Distal and proximal risk factors of problematic cannabis use associated with psychotic-like experiences

BACKGROUND

Problematic cannabis use is associated with endorsement of psychotic-like experiences (PLEs) in non-clinical samples. However, little is known in regard to predictors of this relationship, which may be relevant to prevention and intervention. In the present research, we investigate impulsivity and cannabis use motives as potential distal and proximal risk factors for PLEs using conditional process analysis.

METHODS

Using an online cross-sectional survey of N = 300 students, we assessed endorsement of PLEs using the Community Assessment of Psychic Experiences (CAPE), problematic cannabis use with the Cannabis Use Disorder Identification Test (CUDIT-R), motivations for using cannabis with the Substance Use Motives Measure, and impulsivity using the Urgency and Premeditation, Perseverance, Sensation Seeking, Positive Urgency Impulsive Behaviour Scale (UPPS-P).

RESULTS

All three subscales on the CAPE were associated with significantly higher scores on the CUDIT-R. Before and after covarying for sex, we found that higher CUDIT-R scores mediated the relations between lack of perseverance and negative urgency impulsivity with higher PLE symptoms. Furthermore, the indirect effect of cannabis use on the relationship between lack of perseverance and high negative PLE symptoms was only significant at high and moderate levels of depression-coping, but not at low depression-coping motives.

CONCLUSION

Impulsivity and depression-coping motives may be distal and proximal psychological risk factors for negative PLEs in the context of problematic cannabis use. Our findings are in line with the broader substance use and mental health literature and may be informative for cannabis use treatment targets.

A Causal Approach to Functional Mediation Analysis with Application to a Smoking Cessation Intervention

The increase in the use of mobile and wearable devices now allows dense assessment of mediating processes over time. For example, a pharmacological intervention may have an effect on smoking cessation via reductions in momentary withdrawal symptoms. We define and identify the causal direct and indirect effects in terms of potential outcomes on the mean difference and odds ratio scales, and present a method for estimating and testing the indirect effect of a randomized treatment on a distal binary variable as mediated by the nonparametric trajectory of an intensively measured longitudinal variable (e.g., from ecological momentary assessment). Coverage of a bootstrap test for the indirect effect is demonstrated via simulation. An empirical example is presented based on estimating later smoking abstinence from patterns of craving during smoking cessation treatment. We provide an R package, funmediation, available on CRAN at https://cran.r-project.org/web/packages/funmediation/index.html, to conveniently apply this technique. We conclude by discussing possible extensions to multiple mediators and directions for future research.

On the associations between videoconference fatigue, burnout and depression including personality associations

Videoconference fatigue (hereafter VC fatigue) presents a new psychological construct, which gained momentum in course of the COVID-19 pandemic with the rise of videoconferences taking place in everyday (work-)life. In order to better characterize VC fatigue, it is of importance not only to investigate associations with age, gender and personality (as has been done earlier and will be revisited). Besides, it is crucial to shed light on relevant psychopathological constructs co-occurring with VC fatigue. In the present survey study, based on data from N = 311 participants recruited via the Internet we investigated the associations between VC fatigue, burnout and depression, and we specifically took the personality trait neuroticism as potential predisposing variable into account. These four constructs were robustly positively associated with each other. Moreover, mediation analyses revealed that the positive associations between neuroticism and burnout/depression might in parts be mediated by VC fatigue. However, future studies are needed to disentangle cause and effect between the aforementioned variables. The present study, to our knowledge, is among the first to reveal associations between VC fatigue and psychopathologies. Moreover, in this paper we present a German version of the Zoom Exhaustion & Fatigue scale (ZEF) by Fauville and colleagues.