The researchers did not try to identify the causes of the increase, but they have some theories.

VOA: special.2009.08.06

But first,we report about some special young people who have taken on some big causes.

VOA: special.2009.07.31

Lyrica causes side-effects in some patients, including problems with mental concentration and attention.

VOA: special.2011.08.02

There is some debate about exactly what causes the brain to release endorphins.

VOA: special.2010.06.08

It also causes bad side effects, some of which can be deadly.

VOA: special.2010.01.04

The young people offered prayers for some of his beloved causes.

VOA: special.2009.09.13

Ten of Kennedy's children,grandchildren, nieces and nephews offered prayers for some of Kennedy's beloved causes, including health care as a right for all Americans.

VOA: standard.2009.08.29