title: A caffeine challenge test in panic disorder patients, their healthy first-degree relatives, and healthy controls.
abstract: 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 (chi2=1.81, df=1, P=0.179), and none of the control subjects had a panic attack after the test (chi2=51.7, df=2, P<0.001). In this caffeine challenge test, PD patients and their first-degree relatives were more sensitive than healthy volunteers to the panic attack symptoms but less sensitive to headache, increase in blood pressure, and insomnia. Our data suggest that there is an association between panic attacks after the intake of 480 mg of caffeine in PD patients and their first-degree relatives. There is a clear differentiation of PD patients and their first-degree relatives by a caffeine test from the healthy group.
authors.affiliation: Laboratory of Panic & Respiration, Institute of Psychiatry, Rio de Janeiro, Brazil. antonionardi@terra.com.br
authors.forename: Antonio E
authors.initials: AE
authors.lastname: Nardi
authors.forename: Alexandre M
authors.initials: AM
authors.lastname: Valença
authors.forename: Isabella
authors.initials: I
authors.lastname: Nascimento
authors.forename: Rafael C
authors.initials: RC
authors.lastname: Freire
authors.forename: André B
authors.initials: AB
authors.lastname: Veras
authors.forename: Valfrido L
authors.initials: VL
authors.lastname: de-Melo-Neto
authors.forename: Fabiana L
authors.initials: FL
authors.lastname: Lopes
authors.forename: Anna Lucia
authors.initials: AL
authors.lastname: King
authors.forename: Gastão L
authors.initials: GL
authors.lastname: Soares-Filho
authors.forename: Marco A
authors.initials: MA
authors.lastname: Mezzasalma
authors.forename: Arabella
authors.initials: A
authors.lastname: Rassi
authors.forename: Walter A
authors.initials: WA
authors.lastname: Zin
mesh_terms: D000328:Adult; D001143:Arousal / Q000187:drug effects / Q000235:genetics; D002110:Caffeine; D000697:Central Nervous System Stimulants; D002951:Citrates; D004311:Double-Blind Method; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016584:Panic Disorder / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D010555:Personality Inventory; D010641:Phenotype; D055815:Young Adult