Linear and non-linear measures indicate gastric dysmotility in patients suffering from acute schizophrenia.

Cardiac autonomic dysfunction has been reported in patients suffering from schizophrenia. The aim of the present study was to evaluate gastric electrical activity in unmedicated patients suffering from acute schizophrenia in relation to their symptoms. Electrogastrography was performed before and after test meal ingestion in 26 patients suffering from schizophrenia and 26 matched controls. The non-linear measure approximate entropy (ApEn) was calculated for the first time from the obtained signal in addition to standardized measures. Results were correlated with the scales for the assessment of positive symptoms and negative symptoms. In addition, autonomic and abdominal symptoms were assessed by the autonomic symptom score. We found a significantly increased amount of tachygastria and arrhythmia within the signal of the activity of the gastric pacemaker before and after test meal digestion in patients compared to controls, indicating increased sympathetic modulation within the enteric nervous system. A significant difference was observed for slow wave, which represents the dominant frequency of gastric pacemaker activity, indicating gastric dysmotility in our patients. The elevated ApEn measure points to increased complexity and dysregulation. In addition, we have observed a correlation between delusions and tachygastria. Sympathetic function seems to be altered in the enteric nervous system of patients suffering from schizophrenia. Future studies need to explore the influence of the disease on different branches of the autonomic nervous system and clinical consequences of enteric dysfunction. Our findings point to a possible systemic autonomic imbalance that needs to be studied in respect to the neurobiology of schizophrenia.

Cardio-respiratory coupling indicates suppression of vagal activity in acute schizophrenia.

Altered amygdala activity in patients with schizophrenia can influence respiratory patterns and consequently cardiovascular parameters. Hence, we examined respiration and heart rate time series complexity as well as coupling of both signals. Electrocardiograms and respiratory signals were obtained from 25 unmedicated patients with schizophrenia and controls. Approximate entropy (ApEn) was calculated for heart and respiratory rates as well as cross-ApEn reflecting coupling of both signals. Coupling was decreased indicating diminished vagal modulation at the brain stem level. Regularity of breathing correlated with disease severity. These data might reflect a lack of inhibitory control over brainstem centers in schizophrenia.

Gastric dysmotility in patients with major depression.

BACKGROUND: Depressed patients frequently complain about vegetative symptoms. The aim of the present study was to evaluate gastric electrical activity in patients suffering from major depression in relation to their symptoms. METHODS: Electrogastrography (EGG) was performed before and after a test meal ingestion in 21 patients suffering from major depression and control subjects. A structured interview was used to assess the severity of clinical as well as abdominal symptoms. RESULTS: Patients presented with significantly elevated proportions of tachygastria. Significant differences were found for the parameter arrhythmia, the coefficient of dominant frequency and slow wave after the test meal ingestion. A positive correlation was found between tachygastria and ANS score as well as tachygastria and the item "sweating". LIMITATIONS: Further studies are warranted to include more patients and to investigate interaction with specific antidepressive drugs. DISCUSSION: This is the first study demonstrating an increased amount of tachygastria in patients suffering from major depression which might be caused by increased sympathetic modulation. The correlation of tachygastria with the amount of gastric symptoms underlines the clinical significance of this finding.