Resting State Functional Connectivity in Cannabis Users: The Moderating Role of Cannabis Attitudes

467 

Abstract Submission 

Emese Kroon¹, Yara Toenders¹, Lauren Kuhns², Janna Cousijn¹, Francesca Filbey³

¹Erasmus University Rotterdam, Rotterdam, Zuid-Holland, ²University of Amsterdam, Amsterdam, Noord-Holland, ³University of Texas at Dallas, Dallas, TX

Emese Kroon  
Erasmus University Rotterdam
Rotterdam, Zuid-Holland

Yara Toenders  
Erasmus University Rotterdam
Rotterdam, Zuid-Holland

Lauren Kuhns  
University of Amsterdam
Amsterdam, Noord-Holland

Janna Cousijn  
Erasmus University Rotterdam
Rotterdam, Zuid-Holland

Francesca Filbey  
University of Texas at Dallas
Dallas, TX

The global increase in lenient cannabis policy has been paralleled by reduced harm perception, which appears to affect cannabis use initiation and persistent use (1). Substance use disorders have been associated with altered resting-state functional connectivity (RSFC) in various neural networks, including the executive control network (ECN), salience network (SN), and default mode network (DMN). These alterations are thought to result in increased salience of substance-related cues and introspective processes, combined with a lack of control over the motivational urges to use (2). However, studies on RSFC in cannabis users are limited and yield inconsistent results. Furthermore, given evidence from the growing field of cultural neuroscience - demonstrating interactions between sociocultural factors and brain mechanisms (3) - it is likely that similar sociocultural factors affect the brain processes underlying substance use. Nevertheless, it is unclear how cannabis attitudes may affect brain processes including RSFC underlying cannabis use and cannabis use disorder (CUD)

RSFC within the ECN, SN, and DMN was assessed in 110 near-daily cannabis users with CUD and 79 closely matched controls aged 18-30 from The Netherlands and Texas, USA. Matched scan sequences were used to record an 8-minute T2* functional scan assessing BOLD responses while resting with eyes closed. Participants completed an adapted version of the cannabis culture questionnaire (4), assessing the perceived benefits and harms of cannabis use from their personal, friends-family's and country-state's perspective and reported on their cannabis use (gram/week) and DSM-5 CUD symptoms count. After preprocessing, mean time series were extracted from each of the pre-defined ROI templates of the networks of interest (5) before the activity time series from each network were regressed out of the individual timeseries, resulting in an individual within-network RSFC map for each network of interest. Permutation tests were used to assess 1) group differences in within-network RSFC, 2) associations between the measures of cannabis use and 3) within-network RSFC in the CUD group, and whether cannabis attitudes moderated these associations. Site was added as a covariate to all models to control for potential effects of scanner differences.

RSFC within the dorsal SN was lower in the CUD group than controls, and heavier cannabis use within the CUD group was associated with lower dorsal SN RSFC. Perceived benefits and harms of cannabis use moderated associations of cannabis use (Fig. 1) and CUD severity (Fig. 2) with within-network RSFC of multiple networks of interest. The association between CUD scores and ventral DMN RSFC was less negative in those perceiving more positive country-state attitudes. The association between CUD scores and anterior SN RSFC was positive in those perceiving less negative country-state attitudes, while this association was negative in those perceiving more negative country-state attitudes. Focusing on personal negative attitudes, the association between cannabis use and both dorsal DMN and left ECN RSFC appears to be more negative in those with more negative attitudes. Looking at personal positive attitudes, the pattern is reversed: the association between cannabis use and dorsal DMN RSFC is more positive in those with more positive attitudes.

These results indicate that while positive and negative attitudes appear to have opposite moderating effects when assessed within the same brain region, the direction of the effect is highly dependent on the network/area and show that results from a specific region can be conflicting dependent on its role in different networks. Our findings highlight the importance of considering individual differences in the perceived harms and benefits of cannabis use as a factor in the associations between brain functioning and heaviness of cannabis use and CUD severity.

Psychiatric (eg. Depression, Anxiety, Schizophrenia) ¹

Connectivity (eg. functional, effective, structural)

BOLD fMRI ²

Addictions

ADULTS

FUNCTIONAL MRI

Other - Cross-cultural