Panic attacks are more common in  females than in males, but clinical features or symp-
toms of panic attacks do not di ffer between males and females.
Diagnostic Markers
Physiological recordings of naturally occurring panic attacks in individuals with panic
disorder indicate abrupt surges  of arousal, usually of heart rate, that reach a peak within
minutes and subside within minu tes, and for a proportion of  these individu als the panic
attack may be preceded by cardiorespiratory instabilities.