The impact of ADHD persistence, recent cannabis use, and age of regular cannabis use onset on subcortical volume and cortical thickness in young adults

Abstract

Background-Both Attention Deficit Hyperactivity Disorder (ADHD) and chronic cannabis (CAN) use have been associated with brain structural abnormalities, although little is known about the effects of both in young adults.Methods-Participants included: those with a childhood diagnosis of ADHD who were CAN users (ADHD_CAN; n=37) and non-users (NU) (ADHD_NU; n=44) and a local normative comparison group (LNCG) who did (LNCG_CAN; n=18) and did not (LNCG_NU; n=21) use CAN regularly. Multiple regressions and MANCOVAs were used to examine the independent and interactive effects of a childhood ADHD diagnosis and CAN group status and age of onset (CUO) on subcortical volumes and cortical thickness.Results-After controlling for age, gender, total brain volume, nicotine use, and past-year binge drinking, childhood ADHD diagnosis did not predict brain structure; however, persistence of ADHD was associated with smaller left precentral/postcentral cortical thickness. Compared to all non-users, CAN users had decreased cortical thickness in right hemisphere superior frontal sulcus, anterior cingulate, and isthmus of cingulate gyrus regions and left hemisphere superior frontal sulcus and precentral gyrus regions. Early cannabis use age of onset (CUO) in those with ADHD predicted greater right hemisphere superior frontal and postcentral cortical thickness.Discussion-Young adults with persistent ADHD demonstrated brain structure abnormalities in regions underlying motor control, working memory and inhibitory control. Further, CAN use was linked with abnormal brain structure in regions with high concentrations of cannabinoid receptors. Additional large-scale longitudinal studies are needed to clarify how substance use impacts neurodevelopment in youth with and without ADHD.

Assessing the Role of Cannabis Use on Cortical Surface Structure in Adolescents and Young Adults: Exploring Gender and Aerobic Fitness as Potential Moderators

“…None of the prior studies examining these outcomes tested whether gender or aerobic fitness moderated these effects or controlled for aerobic fitness level. Although we found the relationship between cannabis use and cortical surface structure was moderated by two-way interactions which were observed between gender, cannabis and aerobic fitness in frontal, cingulate, and parietal regions; regions that have been found to be abnormal in previous studies [21,23,24,36,37,39]. Thus, we will focus on these novel interactions.…”

“…Specifically within the United States, cannabis is the second most commonly used substance within adolescents and young adults [2]. Approximately 29.7% of adolescents (Grades 8, 10, and 12) [3] and 52% of young adults (aged [18][19][20][21][22][23][24][25] [4] have used cannabis within their lifetime; and, these prevalence rates can vary by state policies [5]. Heavy and chronic cannabis use is associated with adverse psychopathological [6], neurocognitive, and aberrant brain morphology outcomes [7].…”

Distinct effects of childhood ADHD and cannabis use on brain functional architecture in young adults

“…These findings are in line with those of Tamm et al (2013), who examined neurocognitive performance in an overlapping sample – while individuals with a childhood diagnosis of ADHD exhibited decrements in EFs such as response inhibition and decision-making, there were no significant effects of recent cannabis use and no interactions between ADHD history and cannabis use. Task-based fMRI data collected from an overlapping sample of participants while they performed a Go/NoGo task revealed a similar pattern (Rasmussen et al, 2015), as did an analysis of cortical thickness (Lisdahl et al, 2016). Taken together, these data suggest that weekly cannabis use does not exacerbate underlying neuronal vulnerabilities in individuals with a childhood diagnosis of ADHD.…”

“…It is important to note that this set of findings does not mean that negative effects of cannabis use on brain function are not observed, however. Indeed, analyses examining the impact of age of onset suggest that early age of regular cannabis use onset in participants with ADHD is associated with additional structural abnormalities (Lisdahl et al, 2016) and executive function deficits (Tamm et al, 2013). As emphasized by Batalla et al (2013), large-scale, prospective, longitudinal studies are required to fully delineate the evolution of such effects and the long-term impact of cannabis use on cognitive function and behavior, particularly when use is initiated in adolescence and in the context of neurodevelopmental disorders such as ADHD.…”

The Relation of Focal Lesions to Cortical Thickness in Pediatric Traumatic Brain Injury

“…In contrast, more severely injured children would likely remain longer in the hospital regardless of GCS and in this instance, for the SOBIK TBI group, LOS and GCS controlling for age and sex resulted in different distributions of reduced cortical thickness with both showing reductions in occipitoparietal regions. There may also be a host of other variables that could relate to cortical thickness including pre-injury factors, neuropsychiatric sequelae and medication treatment and/or medical interventions that the SOBIK investigation was not designed to assess 46, 47 . Future studies will need to more thoroughly explore pre-injury and potential treatment variables as they relate to cortical thickness in pediatric TBI.…”