Lack of association between joint hyperlaxity and, I: Panic disorder, and II: Reactivity to carbon dioxide in healthy volunteers

This study attempted to replicate previous reports of associations between panic disorder and joint hyperlaxity. The authors also examined possible associations between reacitivity to carbon dioxide (CO₂), a model for panic vulnerability, and hyperlaxity in healthy volunteers. One hundred and one patients with DSM-IV panic disorder and 39 healthy volunteers were assessed for hyperlaxity by Beighton's criteria. Healthy volunteers also received two vital capacity inhalations of CO₂. Thirteen (13%) patients had five or more hyperlax joints. This rate did not differ from that in the healthy volunteers. Anxiety in healthy volunteers as measured by the NIMH self-rating scale, DSM-IV panic symptom scores, and 100 mm visual analog scales of anxiety, increased after CO₂ from a mean of 1.8 to 2.8 (not significant); from 0.5 to 4 (p<0.001) and from 8.7 to 11.6 mm (p<0.1), respectively. There were no associations between responses to CO₂ and hyperlaxity.