Human beings are an interesting mix of fragility and hardiness, and we have a tendency to overestimate both traits. We also tend to be somewhat over-confident in our own ability to make sense of patterns. This combination of traits often blinds us to the real magnitude of risks we encounter every day---we're often scared of airplanes, but very few people have cigarette phobias. And when we really do get sick, in our desperation our faults often become magnified. As patients we often cast blindly for hope; as doctors we look to give hope, but the hope we give must be qualified by reality.
I would love to tell a patient of mine, "hey, everything's gonna be alright, so don't you worry about a thing." But that's not the way life works. Finding new ways to prevent and treat disease is a slow process and no amount of wishing can speed it up. One of my favorite examples is the discovery of Gleevec, a drug for chronic myeloid leukemia (CML). First, the mechanism of the disease had to be discovered. Then someone had to come up with a molecule to target. Then small trials had to be run to assess the drug for safety and potential efficacy. Then larger trials were done to get a better handle on efficacy and on less common side effects. And when all that worked out, the drug was marketed. Though not a common disease, CML does kill people, and lots of people died waiting for this drug. They also died before anyone knew the cause of the disease and before anyone had conceived of a way to fight it. And they still die, but not as many as used to. Many other candidate drugs to treat CML and other diseases have come and gone, and people have lived and died.
MS sufferers are excited because they now have a more clever medical model that might explain cause rather than the merely descriptive neurological explanation. Don't trash their hopes.
We must not confuse hypotheses with actual treatments. While I hope for effective treatments for many diseases, I cannot change my practice based on hope alone. Many of the comments on my MS post were similar---excitement about a new treatment, anger than anyone should downplay it. But the status quo has not changed. New hypotheses come and go, and people continue to suffer and die of disease. If we start to act on new ideas without proper testing, we usually create suffering by briefly giving people hope and then dashing these hopes against the hard reality of science. Anyone can propose a new treatment for a disease---quacks do this every day, and prey on people's hope while enriching themselves.