Syncope of psychiatric origin

BACKGROUND: A well-defined relationship between transient loss of consciousness and a psychiatric disorder has not yet been established. REVIEW SUMMARY: In the past, psychiatric origin of syncope was considered to be uncommon, occurring only in 1-7% of patients with syncope. Recently, a much higher incidence ranging from 20 % to 81 % has been reported. One main difficulty may be an incorrect approach to the problem. Authors generally defined syncope as every loss of consciousness without regard to the specific pathophysiology of the symptom. Moreover, identification of psychiatric origin of transient unconsciousness may be very difficult. Some clinical features can suggest the diagnosis; none of them, however, is an identification mark. Thus, in most cases, the diagnosis may be certain only when direct observation of the clinical event occurs. A transient loss of consciousness may be related to a psychiatric disorder when the symptom ensues in the presence of normal values of both blood pressure and heart rate. The phenomenon resembles syncope and has been defined as "pseudosyncope". Unfortunately, direct observation of a spontaneous event is very uncommon. Recently, few cases of pseudosyncope induced by Tilting test (HUTT) have been reported. In these patients, HUTT revealed a previously unknown psychiatric disorder. In our experience, pseudosyncope represented an uncommon HUTT outcome in all patients referring for unexplained syncope; in selected patients, however, HUTT may be useful in the early identification of psychiatric syncope. CONCLUSIONS: Prospective researches are needed to assess HUTT utility in evaluating patients whose clinical features suggest psychiatric origin of transient loss of consciousness.