When you're suffering from a life-changing illness, where do you find information about its likely progression? How do you decide among treatment options?

You don't want to rely on studies in medical journals because their conclusion-drawing methodologies are haphazard. You'll be better off getting your prognosis and treatment decisions from a social networking site: PatientsLikeMe.com.

PatientsLikeMe.com lets patients with similar illnesses compare symptoms, treatments and outcomes. As Jamie Heywood at TEDMED 2009 explains, this represents an enormous leap forward in the scope and methodology of clinical trials. I highly recommend his excellent talk, and I will paraphrase part of it below.

Here is a report in the Proceedings of the US National Academy of Sciences (PNAS) about Lithium, which is a drug used to treat Bipolar disorder that a group in Italy found slowed ALS down in 16 patients. When PNAS published this, 10% of the patients in our system started taking Lithium, based on 16 patients' data in a bad publication.

This one patient, Humberto, said, "Can you help us answer these kinds of treatment questions? I don't want to wait for the next trial; I want to know now!"

So we launched some tools to help patients track their medical data like blood levels, symptoms, side effects... and share it.

People said, "You can't run a clinical trial like this. You don't have blinding, you don't have data, it doesn't follow the scientific method -- you can't do it."

So we said, OK, we can't do a clinical trial? Let's do something even harder. Let's use all this data to say whether Lithium is going to work on Humberto.

We took all the patients like Humberto and brought their data together, bringing their histories into it, lining up their timelines along meaningful points, and integrating everything we know about the patient -- full information about the entire course of their disease. And we saw that this orange line, that's what's going to happen to Humberto.

And in fact he took Lithium, and he went down the line. This works almost all the time -- it's scary.

So we couldn't run a clinical trial, but we could see whether Lithium was going to work for Humberto.

Here's the mean decline curve for the most dedicated Lithium patients we had, the ones who stuck with it for at least a year because they believed it was working. And even for this hard core sample, we still have N = 4x the number in the journal study.

When we line up these patients' timelines, it's clear that the ones who took Lithium didn't do any better. And we had the power to detect an effect only 1/4 the strength of the one reported in the journal. And we did this one year before the time when the first clinical trial, funded with millions of dollars by the NIH, announced negative results last week.