We (as in the Royal We) here at The Neurophile, Inc. consider it an essential part of our daily tasks to track down and bring to your attention examples of exaggeration in popular science articles about drugs and addiction. Today we have for your perusal a classic example of this innate tendency towards hyperbole of this sort. We noticed in our RSS links the other day a ScienceDaily article with the title, Both Alcoholism And Chronic Smoking Can Damage The Brain's Prefrontal Cortex.
As we are always keeping a keen eye out for intriguing articles about drug addiction, we immediately noted it for later viewing. Upon reading it today, the first thing that came to our attention: nowhere in the article is potential damage caused by alcohol consumption or smoking mentioned. In fact, the journal article they are referring to has a much more conservative (not to mention technically accurate) title: "Chronic Smoking and Alcoholism Change Expression of Selective Genes in the Human Prefrontal Cortex." So a change in gene expression = brain damage?
Oh, I don't think so.
However, it is an intriguing article nonetheless. Basically, they seem to be looking at some genes that seem to be implicated in the neural response to chronic alcohol use but have had some contradictory reports of the changes in expression. They theorized that these differences are due to inattention to the comorbidity between heavy alcohol use and heavy smoking. So they did a comparison between both smoking and nonsmoking alcoholics and nonalcoholics, vs. both alcoholic and nonalcoholic smokers and nonsmokers. This allowed them to distinguish between those effects that are due to smoking, those that are due to chronic alcohol use, and those that are due to interactions between the two. In this respect, it's all quite neat.
Although they did find some evidence of potential damage to the prefrontal cortex (PFC), it's all by implication. One of the genes, GLAST1, is a glial glutamate transporter which can be upregulated in response to excitotoxicity caused by excessive glutamate. Two of the other genes, MDK and TIMP3, can also be potential signs of excitotoxicity or drug-induced apoptosis. However, this is far from being a conclusive explanation for the change in expression in this instance, and the authors of the article make no attempt to claim it is anything more than conjecture at this point.
It is of note that alcoholism is well known to induce some long-term damage to the PFC, in the form of a loss of grey and white matter. However, a cursory review of the article refers to a role of smoking in changing grey and white matter levels in temporal and parietal areas (see picture here), but I saw no mention of any direct evidence that smoking actually causes damage to the PFC itself.
So the title of the ScienceDaily piece seems to just be an attempt to grab some attention by making a claim that the article they're talking about doesn't even attempt to support. Sigh.
On the upside? I was mightily impressed by their one paragraph explanation of what gene expression means:
All of our cells have exactly the same deoxyribonucleic acid (DNA), which means they all have the same genes. Different cells can appear and work so differently with the same genes (giving us, for example, unique eyes, skin, hair, etc.) because only some genes are used or 'turned on' in each cell. This is called gene expression. The sequence of events is for DNA, or genes, to make ribonucleic acid (RNA), also called a 'message,' which is then used to make proteins. These proteins determine the appearance and function of each cell and, in turn, the proteins' existence depends on gene expression. Thus, gene expression is a normal function of all cells and is well regulated by the body to avoid mistakes.
I'm not just impressed that they covered it so well with great brevity, I'm incredibly impressed that they covered it at all. It's the sort of things that too often gets glossed over due to lack of space and the desire to get to the meaty bits of someone's results. So for that part, at least, we here at the Neurophile salute ScienceDaily.
But cut down on the fear-mongering a bit, okay? It's not like we don't already know that alcoholism and heavy smoking are bad for us.