Advertised Explanations of How SSRI Anti-Depressants Work May Be Misleading

A new commentary in PLoS Medicine (full citation: Lacasse JR, Leo J (2005) Serotonin and Depression: A Disconnect between the Advertisements and the Scientific Literature. PLoS Med 2(12): e392 ) suggests that direct-to-consumer advertisement (DTCA) of the newer selective serotonin reuptake inhibitor (SSRI) medications for depression and anxiety may be misleading.
In particular, such advertisements sometimes suggest that these drugs correct an imbalance of serotonin chemistry in the brain. For example, the article quoted these advertisements:

• “Celexa helps to restore the brain’s chemical balance by increasing the supply of a chemical messenger in the brain called serotonin."
• “When you’re clinically depressed, one thing that can happen is the level of serotonin (a chemical in your body) may drop. So you may have trouble sleeping. Feel unusually sad or irritable. Find it hard to concentrate. Lose your appetite. Lack energy. Or have trouble feeling pleasure…to help bring serotonin levels closer to normal, the medicine doctors now prescribe most often is Prozac®”
• “Chronic anxiety can be overwhelming. But it can also be overcome…Paxil, the most prescribed medication of its kind for generalized anxiety, works to correct the chemical imbalance believed to cause the disorder."
• “While the cause is unknown, depression may be related to an imbalance of natural chemicals between nerve cells in the brain. Prescription Zoloft works to correct this imbalance. You just shouldn’t have to feel this way anymore”

Providing such a physiologic explanation for these drugs' actions makes it more plausible that they benefit patients.
Yet the theory that depression or anxiety are due to imbalances in brain levels of serotonin is just that. There is no proof that it is correct, and in my humble opinion, it seems overly simplistic given our increasing but still fragmentary understanding of neuroscience. Thus the advertisements may be misleading because they provide seemingly authoritative mechanistic explanations of why these drugs should work that are not necessarily true.
Again, neither patients nor doctors are served well by potentially misleading marketing, especially when there are new questions whether the class of drugs being marketed is really superior to older (and cheaper) alternatives.
Thanks to Schwitzer's Health News blog for the tip.