Why is it that the cocaine/Ritalin analogy continues to cause such a stir?

‘Kiddie Cocaine: Behavior Drug Ritalin Abused by Children’

Headlines such as this one (CBS news, February 11th 2009) have justifiably shocked parents worldwide.
Let’s examine this claim and its implications.

Could it mean, Ritalin is addictive like cocaine?

It isn’t. This is because methylphenidate, unlike cocaine, has very little effect on the nucleus accumbens, the area of the brain which mediates euphoria and substance dependence. The rate of uptake into the brain is critical here. Taken orally, Ritalin gets there too slowly to affect this part of the brain. If you take the time and trouble to crush methylphenidate tablets, and then snort or inject the powder, you can certainly induce euphoria, but prescribed in therapeutic doses and taken correctly, you don’t get high on Ritalin.

Could it mean, Ritalin will increase the risk of later drug abuse?

It won’t. The overwhelming message from the scientific literature is that neither ADHD nor its treatment has much bearing at all on the likelihood of eventual substance abuse. The most important factor influencing the risk for later drug abuse is the presence of conduct disorder, a condition characterised by serious violations of societal rules. If anything, stimulant treatment into adolescence is actually protective against this outcome, probably because of reduced impulsiveness, better social functioning and improvements in self-esteem, which have all been independently shown to minimise the risk of drug abuse.

Then surely it must mean, Ritalin wrecks lives like cocaine?

It doesn’t. There is a wealth of research which attests to the positive outcomes of those appropriately treated with ADHD medication. In whichever domain you care to mention, be it academic, social, emotional or interpersonal, this treatment enhances the quality of life of those who need it.

So what does it mean? Is there a grain of truth in this analogy?

On a neurochemical level, both substances affect the dopamine transporter, which controls the amount of dopamine available in the synapse between cells. They both block it, resulting in an increase in the available dopamine (albeit in different parts of the brain). But this is about the extent of the similarity. Like me, you may have experienced the sense of wellbeing derived from cardiovascular exercise. It is well documented that a good workout results in the release of naturally-occurring endorphins, which interact with specific receptors in the brain, causing a mild euphoria. This explains why some long-distance runners get ‘addicted’ to their exercise. As it turns out, opioid drugs such as morphine and heroin act on the very same brain receptors.

Surely you will not use this coincidence of chemistry to condemn my exercise habits?