Implicit memory bias for threat in panic disorder: application of the 'white noise' paradigm.

We employed Jacoby's white noise paradigm to investigate implicit memory bias for threat in panic disorder and in normal control subjects. Subjects heard a series of neutral sentences (e.g. "The shiny apple sat on the table") and panic sentences (e.g. "The anxious woman panicked in the supermarket"). Implicit memory for this prior exposure was then tested by having subjects rate the volume of white noise accompanying the presentation of 'old' sentences intermixed with 'new' sentences. Implicit memory for old sentences is revealed when subjects rate the white noise accompanying these sentences as less loud than noise accompanying new sentences. Results revealed that under low noise level, panic patients demonstrated an implicit memory bias for threat information, whereas control subjects did not. This differential priming effect suggests that information about threat may be automatically accessed in these patients.