Deep Brain Stimulation of the Subthalamic Nucleus in Parkinson's Disease: A Meta-Analysis of Mood Effects

This meta-analysis examines mood changes after bilateral subthalamic deep brain stimulation (STN-DBS) in patients with Parkinson's disease (PD). Deep brain stimulation improves motor outcomes in Parkinson's disease but there appears to be conflicting reports as to subsequent mood outcomes. Pubmed, PsychINFO and SCOPUS were searched for studies assessing mood outcomes in PD patients who had undergone STN-DBS published between January 2003 and the end of January 2019. Random effects meta-analyses were conducted for all outcome groups with at least two studies homogenous in design and measure. Forty-eight studies, providing data on negative moods (such as depression, anxiety, apathy, and anger) and positive moods (pleasure and euphoria) were assessed. Results of the meta-analysis suggest that post-DBS, depression and anxiety symptoms improve and there is a reduction in negative affect, an increase in apathy, and in energy level. Although there have been reported cases of mania post-DBS surgery, the meta-analysis suggested no significant changes in symptoms of mania in the broader DBS population. Considerable heterogeneity was found and partially addressed through meta-regression and qualitative assessment of the included STN-DBS controlled studies. The major strengths of this meta-analysis, include attention to outcome validity, heterogeneity, independence of samples, and clinical utility, with the potential to improve post-operative safety through comprehensive consideration of mood and psychological adjustment. It appears that STN-DBS is a relatively safe and, in the case of mood symptomatology, an advantageous treatment of Parkinson's disease.