To date, the quantitative psychopathology of panic disorder (PD) has b
een less well studied than that of other psychiatric conditions such a
s schizophrenia or major depression. The aim of the present study was
to assess the frequency and factorial grouping of symptoms in a natura
listic sample of PD patients. A total of 274 consecutive cases of PD w
ho contacted an out-patient clinic in Barcelona, Spain were assessed b
y two experienced interviewers. The assessment instruments included th
e Structured Clinical Interview for DSM-III-R Upjohn version (SCID-UP-
R) and an inventory of panic attack symptoms based on DSM-III-R. Of th
e patients who presented at the unit during the assessment period, 8.5
% presented with PD. Palpitations, shortness of breath, fear of dying
and dizziness were the most frequent and intense symptoms reported by
the PD patients. Principal-component analysis revealed four factors wh
ich accounted for 57% of the variance, including 'cardiorespiratory' (
26.1%) and 'vestibular' (15.1%) factors, and two additional factors wi
th mixed symptoms. The frequency of presentation of symptoms was simil
ar to that reported in other studies. However, some discrepancies were
observed that may be attributed to transcultural differences as well
as to terminological problems and the range of symptoms assessed. Thes
e factors may also explain some of the differences found in factor ana
lysis groupings in previous studies. Our findings support the symptom
subtyping of PD.