• clinical epidemiology;
  • functional impairment;
  • syncope

To determine the principal causes and effects of syncope in young adults, we prospectively evaluated 197 consecutive patients referred to a Syncope Specialty Clinic, comparing young (age 16–39 years, n = 71), middle-aged (age 40–65 years, n = 70) and elderly (> age 65 years, n = 56) patients. Psychiatric aetiologies were significantly more common in young patients (39% vs. 20% in middle-aged, and 3.6% in the elderly; P < 0.001), while cardiac aetiologies were rare in the young (2.8% vs. 12% in the middle-aged, and 16% in the elderly; P < 0.04). These differences were still significant after controlling for gender. Because psychiatric causes are so common in young patients, we evaluated hyperventilation as a bedside test for syncope patients and found it to have a positive predictive value of 59% for psychiatric causes of syncope. Syncope interfered with daily activities in 62% of young patients, and resulted in anxiety or depression in 70% of the young (no difference when compared with other age groups). Thus syncope in young adults can be a disabling medical condition requiring a unique medical and psychological approach to diagnosis and treatment.