A caffeine challenge test in panic disorder patients, their healthy first-degree relatives, and healthy controls

Our aim was to observe the induction of anxiety symptoms and panic attacks by a caffeine challenge test in panic disorder (PD) patients (DSM‐IV) and their healthy first‐degree relatives. We randomly selected 25 PD patients, 27 healthy first‐degree relatives of probands with PD, and 22 healthy volunteers with no family history of PD. In a randomized double‐blind experiment performed over two occasions 7 days apart, 480 mg caffeine and a caffeine‐free solution were administered in a coffee form. Using specific panic attack criteria, 52.0% (n=13) PD patients, 40.7% (n=11) first‐degree relatives (χ2=1.81, df=1, P=0.179), and none of the control subjects had a panic attack after the test (χ2=51.7, df=2, P