Rapid onset: a valid panic disorder criterion?

This study examined the value of the DSM-IV time criterion for panic disorder (PD) requiring an abrupt onset to panic attacks (PAs) with a time to peak intensity (TTPI) of less than 10 min, and evaluated features distinguishing rapid onset (TTPI < 10) from prolonged onset (TTPI > 10) panickers. Eight hundred and sixty-four respondents to the National Institute of Mental Health Panic Disorder Questionnaire (NIMH PQ) who met the first three PD criteria were compared based on the time criterion. The prolonged onset panickers (18.2%) did not differ significantly from rapid onset panickers (81.8%) on any of 100 items assessing clinical symptoms, course of illness, and comorbidity of PD. These results suggest that many patients with otherwise classic features of PD have a prolonged TTPI of PAs, and that patients with prolonged-onset PAs are similar to patients with rapid-onset PAs on most measures. The reliability, validity, and clinical relevance of the current DSM-IV TTPI criterion should be evaluated in future studies.