Cardiac autonomic tone, plasma BDNF levels and paroxetine response in newly diagnosed patients of generalised anxiety disorder.

Objective: The study examined the effect on cardiac autonomic tone via heart rate variability (HRV), brain derived neurotrophic factor (BDNF) in newly diagnosed generalised anxiety disorder (GAD) cases with paroxetine-controlled release (PX) CR intervention.Methods: Fifty GAD cases using DSM-5 criteria, matched with healthy controls (HC) were assessed with clinical measures (Hamilton Anxiety Scale (HAM-A), Clinical Global Impression- Severity Scale (CGI-Severity), General Health Questionnaire -12 (GHQ-12), HRV, plasma BDNF levels initially and 6 weeks postintervention with paroxetine CR.Results: HRV parameters were significantly lower in GAD vs HC at baseline for standard deviation of normal to normal intervals (SDNN) and proportion of differences in consecutive NN intervals that are longer than 50 ms (pNN50). Significantly higher plasma BDNF levels were noted between HC versus GAD at baseline. Postintervention HAM-A, CGI scores, GHQ-12 item scores showed significant reduction. Significant differences also noted in square root of mean squared difference of successive NN intervals (RMSSD), (SDNN), pNN50 and in plasma BDNF levels after intervention within GAD group. Significant negative correlation observed between HAM-A scores and SDNN parameter after taking PX CR in GAD.Conclusion: GAD showed cardiac autonomic dysfunction, lowered plasma BDNF levels and their improvement with paroxetine CR.Key messageGAD is associated with significantly lower HRV, suggestive of cardiac autonomic dysfunction and lowered plasma BDNF levels, an indicator of stress.Therapeutic intervention with Paroxetine in GAD patients showed clinically significant improvement reflecting restoration of the cardiac autonomic tone and BDNF levels, thus implying their role as potential biomarkers.