Chronic fatigue syndrome (CFS) is a debilitating condition that leaves its suffers with many questions but few answers. CFS’s causes are poorly understood, there’s no cure, and there isn’t a definitive way to screen for it.

Now, scientists say they’ve taken a big step toward developing a test to diagnose this confusing and complex disorder that leaves patients with symptoms that range from extreme exhaustion, chronic pain, persistent brain fog, and more.

In a new study published in the