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

Drug Alcohol Depend. 2016 Apr 1:161:135-46. doi: 10.1016/j.drugalcdep.2016.01.032. Epub 2016 Feb 6.

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.

Keywords: ADHD; ADHD persistence; Cannabis; Cortical thickness; Early onset; MRI; Marijuana; Young adults.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Age of Onset
  • Attention Deficit Disorder with Hyperactivity / diagnosis
  • Attention Deficit Disorder with Hyperactivity / pathology*
  • Attention Deficit Disorder with Hyperactivity / psychology
  • Case-Control Studies
  • Cerebral Cortex / pathology*
  • Female
  • Frontal Lobe / pathology*
  • Gyrus Cinguli / pathology*
  • Humans
  • Longitudinal Studies
  • Magnetic Resonance Imaging
  • Male
  • Marijuana Smoking / psychology*
  • Neuroimaging
  • Young Adult