Predictability, controllability, and fear of symptoms of anxiety in epinephrine-induced panic

Background: Psychological manipulations (supplied information, safety cues) may influence panic rates during pharmacologic challenge tests in subjects with panic disorder (PD). Psychological panic models assume that fear of stress-related bodily sensations is central to the etiology of PD. Methods: Prior to infusion of epinephrine, 50 subjects with PD were randomly assigned to one out of four experimental conditions: with or without extensive information and with or without external control, according to a 2 × 2 design. The panic rate was hypothesized to be lower in subgroups possessing extensive information and/or control. Fear of bodily sensations was used as a predictor. Results: Thirty-four out of 50 patients (68%) panicked during the infusion. Subjects who received extensive information were marginally less likely to panic, but manipulation of control did not influence panic rates. Panickers did not differ from nonpanickers in measures of fear of fear. Anxiety sensitivity best predicted baseline anxiety and cognitive symptom scores, but was not associated with other outcome measures in panickers. Only baseline partial pressure of CO2 discriminated between panickers and nonpanickers. Conclusions: Manipulating external safety cues appears to be of limited value in modulating responses to epinephrine challenge. Together with our finding that fear of anxiety symptoms does not predict panic rates, these data argue against “fear of fear” as a key mechanism in epinephrine-induced panic.