A new study published in Nature Mental Health has identified overlapping genetic factors between attention-deficit hyperactivity disorder (ADHD) and cannabis addiction. Researchers discovered 36 shared genetic loci that connect ADHD with cannabis use disorder, providing valuable insights into this troubling comorbidity. Notably, the findings highlight how ADHD’s impulsivity and other traits may render individuals more vulnerable to developing substance dependence, particularly cannabis addiction.

ADHD, a neurodevelopmental condition affecting 5% of children and 2.5% of adults globally, already carries a strong genetic component, with heritability estimated at 74%. This study further explored how shared genetic components contribute to a higher risk of cannabis dependency in individuals with ADHD, especially young adults. People with ADHD have a tenfold increased likelihood of developing substance use disorders, with cannabis use disorder being particularly prevalent.

Through rigorous genome-wide association studies leveraging tens of thousands of genetic datasets, scientists pinpointed genetic regions influencing brain development and dopamine systems, deepening our understanding of these disorders. The DRD2 gene, linked to dopamine reception, played a critical role in both ADHD and cannabis addiction, reflecting dopamine’s established connection to both behavioural disorders and addictive patterns.

Polygenic risk scores further revealed that individuals with both ADHD and a genetic predisposition for cannabis addiction faced a 22% absolute risk of developing dependence—significantly higher than 1.6% in controls without ADHD. Gender differences proved noteworthy, with men in the highest-risk group 10% more likely than women to develop cannabis use disorder. These findings stress the importance of early identification and prevention for those genetically predisposed.

While the study advances understanding of genetic vulnerabilities, it also underscores the dangers of cannabis use and its addictive potential. Researchers noted limitations, including a focus on individuals of European ancestry and broad definitions of cannabis use, paving the way for more refined research. However, the evidence reveals the distinct and biologically significant genetic pathways linking ADHD to cannabis dependence, raising compelling questions on preventing substance addiction.

Source: PsyPost