The Cleveland Clinic says the cause of cluster headaches is in a brain area known as a trigeminal-autonomic reflex pathway.

VOA: special.2010.03.30

Several years later, researchers discovered the exact cause of pellagra: a lack of the B vitamin known as niacin.

VOA: special.2009.01.27

Anything you see as a problem can cause stress.

VOA: special.2009.03.24

Stuttering's cause has long been a mystery, but it has frequently been diagnosed as a psychological problem.

VOA: standard.2010.02.11

I do not believe we can come to simple conclusions when it comes to the cause and effects of such a complex disorder as autism."

VOA: standard.2010.08.09

Greenhouse gas emissions such as carbon dioxide are thought to be a major cause behind rising temperatures that have lead to extreme weather and food shortages.

VOA: standard.2009.09.28

President Obama endorsed off-shore drilling as part of a comprehensive strategy, but he has halted new drilling projects until investigators determine the cause of the BP accident.

VOA: standard.2010.05.02

Gohel says what no one could have predicted at the time was how Wilson's support for Afghanistan's mujahedeen would encourage Muslims from around the world to rally to their cause or what would come as a result.

VOA: standard.2010.02.11