The short answer from my reviewing of the literature? Not much. And it had so much POTENTIAL!
Dangit that’s like blowing the punchline before I tell the joke. I must be becoming my mother…
So. I’d like to start this post out with a shout out to the last author (last author on a paper is traditionally the most badass position), Dr. Nora Volkow.
(From wikipedia)
Dr. Volkow is the current head of the National Institute on Drug Abuse, part of the National Institute of Health. She’s a masterful researcher, a great administrator, and one heck of a brilliant mind (she’s also Trotsky’s great-granddaughter! The things you learn.). As a woman in science, and a woman in drug abuse research, Sci finds it REALLY amazingly cool to go to a conference, look up at the keynote speaker, and see a woman in one of the most powerful positions in my field, publishing like gangbusters, and generally being awesome. It makes me hopeful and confident that we are getting somewhere, and that someday, I could do the same. You are an Inspiration with a capital I, Dr. Volkow!!
Anyway, back to the subject at hand.
As you might be aware, cocaine is a stimulant. Interestingly, Ritalin (the chemical name is methylphenidate) is ALSO a stimulant, just longer acting (and much lower dosing when given as a pill). Given that we have been able to successfully treat opiate addictions like heroin with similar, but longer acting drugs like methadone, scientists have been very curious if it would be possible to treat cocaine addiction like we treat heroin addiction, only instead of using methadone, use Ritalin as the replacement. The idea is that Ritalin would stop the craving for cocaine that coke users experience, and so be able to prevent relapse to drug abuse. The more you prevent relapse, the longer that person stays clean, and the better chances they have at staying clean in the long term.
Unfortunately, it didn’t work. Ritalin, at the oral doses we usually give for treatment of ADHD and narcolepsy, etc, doesn’t appear to do much to affect cocaine craving in humans. Other studies are trying Adderall with a little more success. But in the meantime, the question remains. Can stimulants like Ritalin treat people with cocaine abuse? And what benefits would it have?
Goldstein et al. “Oral methylphenidate normalizes cingulate activity in cocaine addiction during a salient cognitive task” PNAS, 2010.
We’re going to start with a place in the brain called the anterior cingulate cortex. We call it the ACC.
Whoops.
(Source)
This is an area of the brain that is interestingly messed up in patients with certain types of disorders. It’s been implicated to play a role in cognitive and emotional control, and people with disorders such as post traumatic stress disorder, depression, and drug addiction have issues in this area. In the case of drug addiction, addicts (such as cocaine addicts) have lower activity in this area compared to controls when they are doing a cognitive task.
So in this study, the scientists wants to see how treatment with Ritalin changed the low activity in coke addicts’ ACCs during a cognitive task. They took 13 coke users and 14 controls (controls used no cocaine, the coke users had used on average 13 times in the last month, and had used for, on average, 18 YEARS). They stuck them in an fMRI and gave them a cognitive task.
The task went like this: You get two types of words on the screen. One type is neutral (a word like, say “boxing” or “inside”), and the other type is drug related (“smoking” or “high”). Each word appears in a COLOR, and the patients had to press a keypad corresponding to the color. During this task, there were two kinds of errors they could make: errors of omission and errors of comission. An error of omission is when you miss a response and don’t respond at all, while an error of comission is when you make the wrong response.
They then gave the patients Ritalin and looked to see what happened.
On the left is a graph showing the change in BOLD signals. BOLD is blood oxygen level dependent, and it is thought to be a measure of activity in a given brain area. You can see that the coke users had a low response in the ACC when presented with drug cues (dark bars, second set from the left in the left graph). Giving them Ritalin (the set of bars on the far left) brought their ACC activation up to normal levels, and maybe a little higher than controls (the two sets of bars on the far right of the left graph). The coke addicts displayed a much bigger change following Ritalin than controls did.
The graph on the right shows the number of errors the patients made, and you can that that Ritalin decreased the number of errors of comission in both the coke patients and the controls.
This was their basic main finding, though they also found a correlation between decreased ACC activity and alcohol consumption in their patients and controls, it didn’t affect the main improvement following Ritalin.
So this seems nice, and like Ritalin may help with the low activity in the brain during a cognitive task. But WILL IT? After all, you can see in the errors graph that, even though the coke users had lower activation in the ACC during the cognitive task…they didn’t PERFORM worse. They performed just the same as controls, in fact. The Ritalin improved their performance, but it improved the performance in the controls as well. The authors conclude that this means that Ritalin could be looked into because “enhancing PFC function and associated cognitive performance (decreasing commission errors/impulsivity), clinical outcome may be improved.” I don’t know about that so much . I mean, yes it improved the PFC function, but it didn’t do much for the cognitive performance because…there was no PROBLEM with the cognitive performance. Was the task not hard enough? The coke addicts not addicted enough? The task not calibrated well enough to pick up differences in this particular brain area? Well dang, we don’t know. But it’s not looking hot for Ritalin in coke addiction treatment right now.
On the other hand, I do want to praise PNAS for being unafraid to publish a paper of what was essentially negative data. That’s something to cheer about right there!
Goldstein RZ, Woicik PA, Maloney T, Tomasi D, Alia-Klein N, Shan J, Honorio J, Samaras D, Wang R, Telang F, Wang GJ, & Volkow ND (2010). Oral methylphenidate normalizes cingulate activity in cocaine addiction during a salient cognitive task. Proceedings of the National Academy of Sciences of the United States of America, 107 (38), 16667-72 PMID: 20823246
