Reversible psychiatric adverse effects related to deep brain stimulation of the anterior thalamus in patients with refractory epilepsy

Abstract

OBJECTIVE: Anterior nucleus of thalamus (ANT) deep brain stimulation (DBS) is becoming a more common treatment for drug-resistant epilepsy. Epilepsy and depression display a bidirectional association. Anterior nucleus of thalamus has connections to anterior cingulate cortex and orbitomedial prefrontal cortex, hence, a possible role in emotional and executive functions, and thus, ANT DBS might exert psychiatric adverse effects. Our aim was to evaluate previous and current psychiatric symptoms in patients with epilepsy undergoing ANT DBS surgery and assess the predictability of psychiatric adverse effects. Programming-related psychiatric adverse effects are also reported. METHOD: Twenty-two patients with ANT DBS for retractable epilepsy were examined, and a psychiatric evaluation of depressive and other psychiatric symptoms was performed with Montgomery and Åsberg Depression Rating Scale (MADRS), Beck Depression Inventory (BDI), and Symptom Checklist prior to surgery, concentrating on former and current psychiatric symptoms and medications. The follow-up visit was one year after surgery. RESULTS: At the group level, no changes on mood were observed during ANT DBS treatment. Two patients with former histories of depression experienced sudden depressive symptoms related to DBS programming settings; these were quickly alleviated after changing the stimulation parameters. In addition, two patients with no previous histories of psychosis gradually developed clear paranoid and anxiety symptoms that also relieved slowly after changing the programming settings. CONCLUSION: The majority of our ANT DBS patients did not experience psychiatric adverse effects. Certain DBS parameters might predispose to sudden depressive or slowly manifesting paranoid symptoms that are reversible via programming changes.