post traumatic stress disorder

Dynamic duos: Why science loves twins

One of the broadest studies of twins in the United States suggests that our genes tend to influence the diseases that afflict us more than where we live, according to research published Monday in the journal Nature Genetics.

What nightmares can tell us about our health

What's your most frequent nightmare? Is it dreaming that you're dying, or that one of your loved ones is suffering but you can't do anything about it? Or maybe you're waking up with confusion and a racing heart, simply glad that the dream ended.