The study investigates the lifetime and 12-month prevalence, symptoms, age of onset and comorbidity patterns of DSM-IV panic attacks and panic disorder in a community sample of 3021 adolescents and young adults aged 14-24 years. Findings are based on DSM-IV symptoms and diagnoses assessed by interviews using a computerised, extended version of the Munich Composite International Diagnostic Interview (M-CIDI). Lifetime prevalence of DSM-IV panic disorder among 14-24 year-olds was 1.6% (0.8% with and 0.8% without agoraphobia). Panic symptoms were found to be quite frequent (13.1%) in the community, with lifetime prevalence of DSM-IV panic attack at 4.3% (12-month prevalence, 2.7%), with first onset rarely before puberty. Women were considerably more likely to have panic disorder and to have an earlier age of onset than males. Occurrence of DSM-IV panic attacks was strongly related to the subsequent development of various forms of mental disorders--not only panic disorder and agoraphobia. The conditional probability in those with panic attacks to develop other forms of mental disorders was 63% in males and 40% in females. Particularly 'late onset' panic attacks (after the age of 18 years) are associated strongly with the development of multimorbidity of mental disorders. This suggests that panic attacks are generally highly indicative for more severe psychopathology and not only for panic disorder and agoraphobia.