Cannabis Use Linked to Weaker Brain Connectivity in Adults with Childhood ADHD

Adults with childhood ADHD who used cannabis showed weaker thalamus-to-parietal brain connectivity compared to non-users, while non-users had stronger-than-normal connections in these regions.

Lee, Sanghyun et al.·PloS one·2022·Preliminary EvidenceCross-Sectional
RTHC-03995Cross SectionalPreliminary Evidence2022RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Cross-Sectional
Evidence
Preliminary Evidence
Sample
N=18

What This Study Found

Cannabis-using adults with childhood ADHD (n=18) had significantly decreased thalamic-parietal functional connectivity compared to non-users (n=15). Non-users showed increased thalamoparietal and thalamofrontal connectivity relative to a normative comparison group.

Key Numbers

18 cannabis users vs 15 non-users with childhood ADHD; 7 normative comparisons; decreased connectivity in inferior parietal regions

How They Did This

Researchers analyzed resting-state fMRI data from the Addiction Connectome Preprocessed Initiative database, comparing thalamic connectivity maps between cannabis users and non-users with childhood ADHD diagnoses.

Why This Research Matters

ADHD and substance use disorders share disrupted brain circuits. Understanding how cannabis interacts with ADHD-related brain connectivity could inform why people with ADHD use cannabis at higher rates.

The Bigger Picture

People with ADHD use cannabis at elevated rates, sometimes reporting self-medication for symptoms. This study suggests cannabis use may weaken brain connections that could otherwise compensate for ADHD-related deficits.

What This Study Doesn't Tell Us

Very small sample size (33 total). Cross-sectional design cannot determine whether cannabis caused connectivity differences or whether pre-existing differences influenced cannabis use.

Questions This Raises

  • ?Do the stronger thalamoparietal connections in non-users serve a protective function against cannabis use?
  • ?Would longitudinal imaging clarify whether cannabis weakens these connections over time?

Trust & Context

Key Stat:
18 cannabis users vs 15 non-users studied
Evidence Grade:
Very small cross-sectional neuroimaging study that cannot establish causation.
Study Age:
Published in 2022
Original Title:
Thalamocortical functional connectivity and cannabis use in men with childhood attention-deficit/hyperactivity disorder.
Published In:
PloS one, 17(11), e0278162 (2022)
Database ID:
RTHC-03995

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study

A snapshot of a population at one point in time.

What do these levels mean? →

Frequently Asked Questions

What does weaker thalamic connectivity mean for ADHD?

The thalamus acts as a relay center for attention and sensory processing. Weaker connections between the thalamus and parietal/frontal regions could contribute to the attention and executive function difficulties seen in ADHD.

Does this mean cannabis worsens ADHD?

The study found an association between cannabis use and weaker brain connectivity in people with ADHD, but the cross-sectional design means it cannot prove cannabis caused the difference.

Read More on RethinkTHC

Cite This Study

RTHC-03995·https://rethinkthc.com/research/RTHC-03995

APA

Lee, Sanghyun; Hong, Soon-Beom. (2022). Thalamocortical functional connectivity and cannabis use in men with childhood attention-deficit/hyperactivity disorder.. PloS one, 17(11), e0278162. https://doi.org/10.1371/journal.pone.0278162

MLA

Lee, Sanghyun, et al. "Thalamocortical functional connectivity and cannabis use in men with childhood attention-deficit/hyperactivity disorder.." PloS one, 2022. https://doi.org/10.1371/journal.pone.0278162

RethinkTHC

RethinkTHC Research Database. "Thalamocortical functional connectivity and cannabis use in ..." RTHC-03995. Retrieved from https://rethinkthc.com/research/lee-2022-thalamocortical-functional-connectivity-and

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.