The World Health Organization Collaborative Study on Psychological Problems in General Health Care examined the form and frequency of, and disability associated with, psychiatric disorders in primary care attenders in 14 countries worldwide. This large multicenter study showed that psychiatric disorders are frequent (24%) among primary healthcare attenders and that significant disability is associated with the mental illness. We present further data from this study, focusing on the comorbidity of psychiatric disorders and the relevance of panic attacks in the primary care setting. Panic disorder is frequently comorbid with depression and this comorbid condition represents a severe form of mental illness. Patients diagnosed with both panic disorder and depression are more likely to have a long-lasting disorder that has an increased severity, results in higher disability levels and is associated with increased suicidality. Panic attacks are indicative of the presence of a depressive disorder, an anxiety disorder or a subthreshold diagnosis in 99 % of patients with current panic attacks. A high symptomatic severity and disability, and increased suicide risk were found in subthreshold cases, particularly if associated with depressive episodes. Thus, panic attacks, which are readily recognized, are characteristic of psychiatric illness and should indicate a high probability that treatment is needed.