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Study breakdown

People With ADHD Start Using Cannabis and Other Drugs Earlier

Cross SectionalModerate evidence
The takeaway

Adults with ADHD and substance use disorder started using substances at a younger age and had higher rates of cannabis, alcohol, and methamphetamine use compared to those without ADHD.

Addiction psychiatrists, ADHD clinicians, and parents of children with ADHD

ADHD group started substance use at a younger age

What the researchers found

The ADHD group had a lower age of onset for substance use. ADHD individuals had higher rates of alcohol, cannabis, methamphetamine, and tramadol use, while the non-ADHD group had higher rates of Ritalin, methadone, ecstasy, morphine, and hypnotics. The pattern suggests ADHD is associated with earlier initiation and preference for stimulating and cannabis-type substances.

Why it matters

The lower age of onset in ADHD has clinical implications: earlier substance initiation is associated with worse long-term outcomes. Identifying ADHD in young people could provide a window for preventive intervention before substance use begins.

The numbers in context

50 ADHD, 90 non-ADHD. ADHD group: higher alcohol, cannabis, methamphetamine, tramadol. Non-ADHD: higher Ritalin, methadone, ecstasy, morphine, hypnotics. ADHD group started substances earlier.

How the study worked

Longitudinal study of 140 adults (50 with ADHD, 90 without) with substance use disorder in addiction detention in Tehran (2021-2022). ADHD diagnosed via SCID and Conner's questionnaire. Onset age and patterns of 10 substances compared.

What this study cannot tell us

Study conducted in addiction detention, limiting generalizability. Small ADHD sample (n=50). Cross-sectional assessment of retrospectively reported onset ages introduces recall bias. Iranian cultural context may differ from other countries.

How to read the evidence

Small clinical sample with validated ADHD diagnosis, but limited by addiction detention setting and retrospective design.

When this study was published

2024 study using 2021-2022 data

The bigger picture

ADHD persists into adulthood in 60% of cases and affects 4% of adults. The overlap with substance use disorders suggests shared neurodevelopmental pathways, with impulsivity and sensation-seeking as potential mechanisms driving earlier and broader substance experimentation.

Questions still open

  • Would treating ADHD earlier reduce substance use initiation? Why do ADHD individuals prefer different substances than non-ADHD individuals? Could cannabis use in ADHD be partly self-medication for attention symptoms?

Common questions

Do people with ADHD use more cannabis?
In this study, adults with ADHD had higher rates of cannabis use (and alcohol and methamphetamine) compared to those without ADHD, and they started using substances at a younger age.
Should ADHD be screened in substance use treatment?
This study supports early ADHD screening, as the ADHD group started substances younger and used a broader range of high-risk substances, suggesting ADHD treatment could be an intervention point.

Read the original research

Patterns of substance use and initiation timing in adults with substance abuse: a comparison between those with and without attention deficit hyperactivity disorder.

Annals of medicine and surgery (2012), 86(8), 4397-4401

Citation

Vaziri-Harami, Roya; Khademi, Mojgan; Zolfaghari, Anahita; Vaziri-Harami, Saharnaz. (2024). Patterns of substance use and initiation timing in adults with substance abuse: a comparison between those with and without attention deficit hyperactivity disorder.. Annals of medicine and surgery (2012), 86(8), 4397-4401. https://doi.org/10.1097/MS9.0000000000002272

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