(The American Journal on Addictions, 17: 504, 2008)
In their article Is Attention Deficit Hyperactivity Disorder (ADHD) Symptom Severity Associated With Tobacco Use* authors Upadhyaya and Carpenter present survey data in which the subjects’ marijuana use and tobacco use, but not alcohol use, vary directly with the severity of attentional symptoms. There was no claim to diagnose ADHD or other mental disorder, including substance use disorders, and data regarding concurrent use of prescription drugs or other drugs of abuse were not collected. The authors conclude that the data suggest attentional symptoms drive the substance use.
If their conclusions were valid, we would expect evidence that the attentional symptoms arose from ADHD or other mental disorder and that the symptoms improved with increased use of the drugs. Instead, the symptoms increase with increased drug use. The data suggest that the attentional symptoms may result from or be worsened by use of marijuana and nicotine rather than resulting from ADHD or other mental disorder. The data do not support a hypothesis that the drug use controls or improves the attentional symptoms.
The absence of data about concomitant use of other prescription or recreational drugs or about other mental or medical illness further limits our ability to draw conclusions form these data. In order to draw conclusions about causality we will need to uncover the applicable mechanisms.
*Upadhyaya HP, Carpenter MJ. Is Attention Deficit Hyperactivity Disorder (ADHD) Symptom Severity Associated with Tobacco Use? Am J Addict. 2008; 17:195-198.