- Very Common:
- lifetime prevalence of 42% of people by the age of 70
- In the general population, the annual number episodes are 18.1–39.7 per 1000 patients, with similar incidence between genders
- 1% of all attendances to ED (of these 50% hospitalized)
- First-time incidence: bimodal distribution
- 15% (below 18 years of age)
- 23% among the elderly
