Schizophrenia Bulletin Advance Access published online on April 14, 2009
Schizophrenia Bulletin, doi:10.1093/schbul/sbp024
Autonomic Dysfunction in Unaffected First-Degree Relatives of Patients Suffering From Schizophrenia
2 Department of Psychiatry and Psychotherapy, Philosophenweg 3, University Hospital, Jena, Germany
3 Department of Psychiatry, Psychotherapy and Psychosomatic Medicine, Ruhr-University, Alexandrinenstr. 1, Bochum, Germany
4 Institute of Physiology I, Teichgraben 8, University Hospital, Jena, Germany
5 Department of Medical Engineering and Biotechnology, University of Applied Sciences, Jena, Germany
6 Rajiv Gandhi University of Health Science, Bangalore, Karnataka, India
7 Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI
8 Department of Psychiatry, University of Alberta, Edmonton, Canada
1 To whom correspondence should be addressed; Department of Psychiatry and Psychotherapy, University Hospital Jena, Philosophenweg 3, 07743 Jena, Germany; tel: +49-3641-935282, fax: +49-3641-936217, e-mail: karl-juergen.baer{at}med.uni-jena.de.
Recent studies revealed cardiac autonomic dysfunction in patients with acute schizophrenia, which appears to be mainly related to reduced vagal and increased sympathetic modulation. To understand the significance of cardiac autonomic function in patients with schizophrenia, we extended these studies to relatives of patients. In this study, we assessed cardiac autonomic modulation in healthy first-degree relatives of patients with schizophrenia (n = 36) to investigate a putative genetic influence. Data were compared with control subjects matched for age, gender, and physical activity as well as to patients suffering from schizophrenia. First-degree relatives showed an attenuated, yet identical pattern in autonomic dysfunction as patients with decreased vagal modulation of heart rate, decreased baroreflex sensitivity, but no difference in blood pressure variability could be detected. The patients' relatives also showed a similar pattern in regards to QT variability. In addition, the subgroup comparison of offspring vs. siblings showed a significant difference in heart rate variability suggesting a higher degree of heritability in offspring. In conclusion, the pattern of autonomic dysfunction seen in patients and relatives might indicate underlying disease-inherent genetic vulnerability, especially because autonomic parameters are heritable. In addition, these findings may be of value to identify the high-risk group of patients' relatives in regards to serious cardiovascular events so that early preventive measures can be taken.
Keywords: autonomic nervous system / schizophrenia / vagal / offspring / heart rate variability / baroreflex sensitivity / genetic