Study: Double-Jointed People More Anxious

Someone recently shared with me this Scientific American article on the link between joint hypermobility and anxiety.  Here's an excerpt:

Being double-jointed has long been linked with an increased risk for asthma and irritable bowel syndrome, among other physical disorders. “Joint hypermobility has an impact on the whole body and not just joints,” says Jessica Eccles, a psychiatrist and researcher at the University of Sussex in England. It was only a matter of time before scientists also looked at whether joint hypermobility was linked to mental disorders. The investigation began in 1993 and heated up in 1998 when researcher Rocío Martín-Santos, now at the Hospital Clinic of the University of Barcelona, and her colleagues discovered that patients with anxiety were 16 times more likely to have lax joints. Their findings have since been replicated numerous times in large populations.

They even posit a potential mechanism for this connection: Collagen abnormalities that enable flexibility also lead to increased cardiac output in stressful situations, which means that people with this condition may experience "exaggerated cardiovascular responses," which they interpret as anxiety. 

In any case, I like to see findings like this, which link anxiety disorders to seemingly unrelated or unlikely risk factors. Because it's not uncommon for people to take responsibility (read: feel guilty) about experiencing elevated anxiety. This goes to show that it's just another heritable, hardwired, physiological trait.