# The mediating role of anxiety and depression symptoms in the relationship between ADHD symptoms and polysubstance use among French university students: the i-share study

## TL;DR

This study finds that ADHD symptoms are linked to polysubstance use among French university students, with anxiety and depression partially mediating this relationship.

## Contribution

The study identifies anxiety and depression as partial negative mediators between ADHD symptoms and polysubstance use in university students.

## Key findings

- ADHD symptoms are positively associated with polysubstance use.
- Anxiety and depression symptoms act as negative and partial mediators between ADHD and polysubstance use.
- No significant sex differences were found in the relationship between ADHD and polysubstance use.

## Abstract

•ADHD factor is positively associated with polysubstance use factor.•Anxiety and depression factors act as negative and partial mediators between ADHD factor and polysubstance use factor.•Multigroup structural equation modeling revealed no significant differences based on sex.

ADHD factor is positively associated with polysubstance use factor.

Anxiety and depression factors act as negative and partial mediators between ADHD factor and polysubstance use factor.

Multigroup structural equation modeling revealed no significant differences based on sex.

Polysubstance use, depressive disorder, and anxiety disorder are frequent comorbidities in adults with ADHD. This study aimed to explore the mediation role of anxiety and depression symptoms in the association between ADHD symptoms and polysubstance use.

The study included 1675 French university students from February 2013 to July 2020 as part of the i-Share cohort. Time 1: ADHD symptoms were assessed using the Adult ADHD Self-Report Scale. Time 2: Anxiety and depression symptoms were evaluated using the State-Trait Anxiety Inventory-Y trait and the Patient Health Questionnaire-9, respectively. Time 3: Substance use was assessed through a self-reported questionnaire. We conducted a mediation analysis using structural equation modeling.

The study included 1675 participants. At time 1, the level of ADHD symptoms was moderate (m: 10.66, sd: 3.99). At time 2, both anxiety (m: 47.11, sd: 10.57) and depression (m: 6.92, sd: 5.33) symptoms were moderate. At time 3, 93.49% (1566) of participants had used substances. The direct effect between ADHD factor and polysubstance use factor was of 1.66 (1.04–2.48). The indirect effects between ADHD factor and polysubstance use factor were through anxiety factor −0.68 (−1.15 to −0.37) and through depression factor −0.57 (−0.94 to −0.32). Although the mediation effects through anxiety and depression factors were negative, the total effect remained positive and significant (0.41 (0.27 to 0.59)).

Anxiety factor and depression factor acted as negative and partial mediators in the association between ADHD factor and polysubstance use factor.