The government has halted a study testing treatments for a condition in the brain that can cause strokes. Early results suggest invasive therapies are riskier than previously thought.

The fairly rare condition involves growing knotted together until eventually some of them burst, causing a bleeding . The question is whether treating these early could prevent that.

Early study results suggest it may be safer to leave these brain tangles alone: Safety monitors found people who received surgery, radiation or other had three times the rate of strokes and death than those given medication for headaches and other symptoms.

The government halted enrollment in the study but participants will be tracked to see how they fare over time.