© 2018 Miraculo Inc. All Rights Reserved
Children diagnosed with attention-deficit/hyperactivity disorder (ADHD) are at increased risk for substance abuse. Response inhibition is a hallmark of ADHD, yet the combined effects of ADHD and regular substance use on neural networks associated with response inhibition are unknown.
Task-based functional Magnetic Resonance Imaging (fMRI) data from young adults with childhood ADHD with (n=25) and without (n=25) cannabis use ≥ monthly in the past year were compared with a local normative comparison group (LNCG) with (n=11) and without (n=12) cannabis use.
Go/NoGo behavioral and fMRI data were evaluated for main and interaction effects of ADHD diagnosis and cannabis use. ADHD participants made significantly more commission errors on NoGo trials than controls. ADHD participants also had less frontoparietal and frontostriatal activity, independent of cannabis use.
Here is the full scientific article if you wish to download it.
No main effects of cannabis use on response inhibition or functional brain activation were observed. An interaction of ADHD diagnosis and cannabis use was found in the right hippocampus and cerebellar vermis, with increased recruitment of these regions in cannabis-using controls during correct response inhibition. ADHD participants had impaired response inhibition combined with less frontoparietal/striatal activity, regardless of cannabis use history.
Cannabis use did not impact behavioral response inhibition. Cannabis use was associated with hippocampal and cerebellar activation, areas rich in cannabinoid receptors, in LNCG but not ADHD participants. This may reflect the recruitment of compensatory circuitry in cannabis-using controls but not ADHD participants. Future studies targeting hippocampal and cerebellar-dependent function in these groups may provide further insight into how ADHD and cannabis use alter this circuitry. While this is all said and done, more studies are still needed on the topic to get a proper evaluation. Cannabis is still relatively new, therefore we still know little about it.