ADHD Patients in Drug Rehab Started Using Cannabis and Cocaine Earlier and Had More Severe Use Patterns

What the researchers found

Researchers evaluated 80 adult patients in therapeutic communities (drug rehabilitation) for ADHD and substance use patterns.

While the overall prevalence of drug use did not differ between ADHD and non-ADHD patients, important pattern differences emerged. ADHD patients were admitted to rehabilitation at younger ages (p=0.004) and first used cocaine at younger ages (p=0.033).

Among ADHD patients specifically, there was a significant negative correlation between age of first cannabis use and subsequent severity of both cannabis use (p=0.017) and cocaine use (p=0.033). In other words, the earlier ADHD patients started using cannabis, the more severe their later use of both cannabis and cocaine became.

Why it matters

ADHD is common among people seeking substance use treatment, and this study suggests it may be associated with different addiction trajectories. The finding that earlier cannabis use in ADHD patients predicted more severe cocaine and cannabis use could inform targeted prevention strategies.

The numbers in context

80 patients studied. ADHD patients had younger admission age (p=0.004) and earlier cocaine initiation (p=0.033). In ADHD patients: earlier cannabis use correlated with more severe cannabis use (p=0.017) and cocaine use (p=0.033).

How the study worked

Cross-sectional study of 80 adult patients in therapeutic communities. ADHD presence and severity were assessed through validated questionnaires, alongside substance use history and patterns.

What this study cannot tell us

The small sample size (80 patients) limits statistical power. The cross-sectional design cannot determine whether ADHD causes earlier substance use or whether other factors are involved. Patients in therapeutic communities represent the most severe end of substance use disorders and may not represent all ADHD individuals who use substances.

How to read the evidence

This is a small cross-sectional study of 80 patients in therapeutic communities, providing preliminary evidence on ADHD and substance use patterns.

When this study was published

Published in 2016. Research on ADHD and substance use trajectories has continued to develop.

The bigger picture

The relationship between ADHD and substance use disorders is well-documented but the specific patterns differ. This study suggests that early cannabis exposure in the context of ADHD may create a particularly problematic trajectory toward more severe substance use.

Questions still open

• Would treating ADHD earlier reduce the risk of early substance initiation and subsequent severe use? Is the ADHD-cannabis-cocaine pathway mediated by impulsivity or self-medication?

Common questions

Read the original research

Attention deficit hyperactivity disorder and drug addiction rehabilitation patients.

Arquivos de neuro-psiquiatria, 74(12), 1003-1007

Citation

Camargo, Carlos Henrique Ferreira; Dornelles, Tarcísio Fanha; Barszcz, Karin; Martins, Eduardo Antunes. (2016). Attention deficit hyperactivity disorder and drug addiction rehabilitation patients.. Arquivos de neuro-psiquiatria, 74(12), 1003-1007. https://doi.org/10.1590/0004-282X20160163

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