What is Your Brain Worth?

According to two European epidemiological studies, approximately one-third of disease resources are spent on neurological disorders, including Parkinson's disease, dementia, and stroke. According to the Alzheimer's Association, someone develops the disease every 72 seconds. That's about the time it will take you to skim this column.

As the population ages, these brain diseases will become even more expensive, complex and challenging. In July, neuroscientist Lars Sundstrom of Southampton University argued in EMBO Reports (8:S40-S43, 2007) that our institutions of science and medicine are not prepared to create a plethora of new drugs to help those with brain disorders. He's right.

To tackle this seemingly-insurmountable problem, Sundstrom proposes that we come up with an entirely new system for finding new drugs that target neurological disorders. Specifically, he suggests we construct in vitro systems that mimic the functions of an entire organ, using tissues generated by stem cells (preferably embryonic). This system would create a perfect "black box," he notes: "A theoretically unlimited supply of human tissue, which can cope with the requirements of modern screening methods and is amenable to automation." He imagines a world in which scientists use stem cells to create human disease models. In theory, this sounds like a great idea.

But is it? Before we get into that, let's take a quick look at what is currently spent on neurological research, and whether the approaches to finding new treatments are working. In Europe, brain diseases cost society €400 billion per year, but the continent dedicates only €855 million in public funds to brain research. If you do the math, it shows that European spending on brain research constitutes 0.2% of what those diseases cost.

Naturally, one might assume that the solution to the enormous public health burden of brain disease is to spend more money on brain research. Spend more, and you'll get more therapies, reducing the public cost of these diseases. But throwing money at the problem does not necessarily work. We already spend millions each year, and have established new brain disorder research centers and institutions in most major academic medical centers. In the United States, where millions suffer from Alzheimer's and Parkinson's diseases, enormous expenditure and political pressure have resulted in little progress in any kind of disease-modifying therapies - and the prevalence rate of these diseases is increasing dramatically.

The reasons are myriad and oft discussed. So-called targeted drug discovery, already highly complex and difficult, is made much more difficult in brain disorders by the fact that we rarely know what is actually "wrong" in a brain disorder. If you don't know the "target," your odds of hitting it diminish to the level of, well, predicting the stock market. This makes me wonder if spending more on brain research will lead to any more products, given that we already spend millions with little result. So even though research constitutes only a miniscule fraction of the social costs of brain research, making that fraction any bigger could be equivalent to throwing our research dollars in the trash, when we could spend them on dozens of diseases - such as those of the heart, kidneys, and liver - for which drug discovery has been fruitful.

And spending even more money to develop and validate an entirely new system seems equally wasteful to me. Using stem cells to generate tissues that mimic the functions of an entire organ will be incredibly expensive, with little indication the effort will result in a usable model. Furthermore, any new approach toward drug discovery will require a paradigm shift in practices of researchers and companies who have pursued another route for decades.

Limited scientific dollars means frugal, intelligent spending on science. New drug discovery for brain disorders is important, and the radical increase in prevalence of brain diseases, and their link to the rest of the body, cannot be ignored. But when it comes to brain research, more is not necessarily better.

Glenn McGee is the director of the Alden March Bioethics Institute at Albany Medical College, where he holds the John A. Balint Endowed Chair in Medical Ethics.