Medically unexplained syncope and its relationship to psychiatric disorders

Abstract

UpdateCurrently, a series of diagnostic tests are available for investigating syncopal episodes. However, in approximately 30% of patients with syncope, the extensive investigations fail to reveal a definite etiology. Recent evidence suggests that a significant portion of these patients may suffer from psychiatric illnesses that lead to recurrent syncope. In the present review, the authors discuss the relationship between medically undetermined syncope and psychiatric illnesses, such as major depression, panic, anxiety and somatization disorders. The patients most likely to develop syncope as a result of psychiatric illnesses are primarily women under the age of 40 years, with multiple previous syncopal episodes and marked presyncopal symptomatology. Although psychiatric syncope should be considered an exclusion diagnosis, it should be remembered, as the referral to a specialist for the institution of a therapy targeting the baseline disease leads to a better prognosis and decreases the occurrence of syncopal episodes.Syncope is defined as a sudden and transient loss of both consciousness and postural tone, with subsequent complete and spontaneous recovery, which does not require cardiopulmonary resuscitation 1 . It is the clinical result of the critical and transient decrease of blood flow to the neurons responsible for maintaining consciousness 2 .Syncope is a frequent condition, accounting for 1% to 6% of all hospital admissions and for 3% of the visits to the emergency department in the United States 3 . In the Framingham Study 4 , which evaluated a cohort study of more than 5,000 patients during 26 years of follow-up, Savage et al suggest that approximately 3% of the population will experience a syncopal episode during their lives. The incidence of this condition can be even higher, approaching 37%, if young patients are evaluated. The prevalence of syncope increases with age, ranging from 0.7% in individuals between 35 and 44 years of age to 5.6% in individuals ≥ 5 years of age. In this same age group, the annual incidence is 6%, with a recurrence rate of 30% 5 . Neurocardiogenic syncope, triggered by the stimulation of intramyocardial receptors, has been recognized as the most frequent, accounting for 50% of the diagnoses 2,6 . The situational syncopes (postmicturition, cough, swallowing or defecation), as well as the carotid sinus syncope, are also neurally mediated. Other possible causes include heart diseases (obstruction and arrhythmias), neurologic diseases (stroke, seizures) and those related to drug use or metabolic disorders (use of vasodilators and hypoglycemia). Thus, the causes of syncope range from benign conditions to potentially fatal diseases. However, in spite of the use of multiple diagnostic tests, in approximately 30% of the patients, a defined etiology for the syncopal episodes is still lacking 7 .Psychiatric illnesses have been underestimated as possible causes of syncope. Actually, results of 3 cohort studies published in the early 80s ( fig. 1) show psychiatric diseases accounting fo...

Prospective evaluation of psychological distress and psychiatric morbidity in recurrent vasovagal and unexplained syncope

“…Female sex and US increased the likelihood of diagnosing psychiatric morbidity by more than threefold. Our results are consistent with findings from other laboratories [21][22][23][24][49][50][51]. For example, in their study examining psychiatric causes of syncope, Linzer et al [23] reported a psychiatric diagnosis in up to 31% of their patients with US.…”

“…Despite this, 22% of patients with recurrent VVS or US continued to suffer from a psychiatric disorder despite the passage of 7 months. Yet, psychological distress and psychiatric morbidity reduce patients' compliance to treatment recommendations [55], interfere with quality of life and functioning [28,50], and are associated with substantial health care costs due to repeated evaluation of somatic symptoms [56,57]. Failure to recognize and adequately treat these patients for their psychological afflictions may therefore complicate medical efforts.…”

“…It is also noteworthy that controlling for number of lifetime syncope episodes eliminated the observed sex differences in psychiatric comorbidity, suggesting that the latter may be a result of the experience of frequent syncope and its consequences on the patients' lives. Indeed, patients themselves tend to attribute depressive or anxiety symptoms to their syncope rather than the reverse [50,51].…”

Psychiatric traits in patients with vasovagal and unexplained syncope

“… 8 , 13 , 16 In addition, when patients were asked about their psychiatric symptoms, the majority attributed them to experiencing syncopal attacks rather than the opposite. 7 , 12 Finally, the fact that psychosocial impairment was observed in patients with other chronic diseases such as chronic obstructive lung disease, 21 end-stage renal disease, 22 and heart failure 23 , 24 suggests that syncope may be a trigger for experiencing psychiatric traits.…”

“… 8 – 11 In addition, it was associated with impaired quality of life. 9 , 12 – 14 Therefore, the psychological and psychiatric profiles may be altered in such population. This hypothesis has been tested before with discrepant results.…”