Whereas Lifetime prevalence rates of panic disorder-as established in epide
miologic surveys-range between 1.6 and 3.5%, 1-month rates usually amount t
o much less than one half of the lifetime rates. This finding indicates tha
t a substantial proportion of patients who had panic disorder at some stage
in their Life must have remitted. In contrast to these results, clinicians
tend to regard panic disorder as a chronic condition because, as a rule, t
hey see panic patients only several years after onset of the disorder. A nu
mber of small, prospective, long-term studies of such clinical populations
indicate that after several years, between 17 and 70% of patients still hav
e panic attacks, and between 36 and 82% have phobic avoidance. In the large
st and longest follow-up study published to date, 45% of all patients showe
d an unremitting-although in a certain proportion waxing and waning-course,
24% followed a pattern of remissions and relapses, whereas 31% went back i
nto a stable remission. The evidence of factors predicting the course of pa
nic disorder in clinical populations suggests that long duration and agorap
hobia at baseline-not the severity and frequency of panic attacks-are predi
ctors of an unfavorable course. Additional studies are needed to determine
whether personality factors, depression, and other variables are also of pr
edictive relevance. Also, factors working during follow-up, such as positiv
e and negative life events, coping behaviors, and treatment, should be cons
idered in future studies.