Deep Brain Stimulation for Psychiatric Disorders: A Systematic Review of Molecular Imaging with PET.

Abstract

Deep brain stimulation (DBS) is an evolving technique for the treatment of various psychiatric disorders refractory to conventional pharmacotherapy. Neuroimaging with positron emission tomography (PET) has an important role in the planning, delivery, and post-surgical monitoring of DBS. This study aims to determine the clinical relevance of PET as a biomarker of disease status and response to DBS for patients with psychiatric disorders. We performed a systematic review of the PubMed, Web of Science, and Scopus databases to identify original research studies that applied PET to study the effects of DBS for patients with psychiatric conditions (major depressive disorder, obsessive-compulsive disorder (OCD), substance use disorder, anorexia nervosa, and schizophrenia). Information on study design, PET findings, clinical measures, and outcomes were recorded. From an initial search of 149 articles, we identified 27 studies on depression (n = 11), OCD (n = 8), substance use disorder (n = 3), anorexia nervosa (n = 3), and schizophrenia (n = 1) that met selection criteria for our qualitative analysis. PET imaging with various radiotracers (¹⁸F-fluorodeoxyglucose (FDG) for glucose metabolism, ¹⁵O-water for cerebral blood flow, ¹¹C-raclopride for dopamine transmission) revealed distinct molecular alterations in patients before and after DBS. Changes in PET signal generally correlated with clinical improvements in psychiatric symptom scores. Comparisons of studies that targeted different brain structures for DBS demonstrated unique activation patterns on PET, though the clinical significance of these changes remains unclear. PET provides insight into the effects of DBS on the molecular activity of the brain, which may improve patient selection for surgery, prognostication, and long-term monitoring.