Trigeminal Nerve Stimulation in Treatment-resistant Generalized Anxiety Disorder: a Feasibility Study

Inclusion Criteria: * Meet the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM5) criteria for generalized anxiety disorder. * Subjects on a stable dose of an selective serotonin reuptake inhibitor (SSRI) or serotonin and noradrenaline reuptake inhibitor (SNRI) for at least 8 weeks. * Treatment-resistant - treatment resistance will be defined as lack of response to at least two drugs, from two different classes of drugs considered first-line or second-line for GAD. Only trials lasting at least 8 weeks, and with at least the minimum effective dose of the given medication will be considered failed trials. Exclusion Criteria: * Moderate to severe major depressive disorder * Moderate to high suicidality * Diagnosis of obsessive compulsive disorder (OCD), PTSD, bipolar disorder, schizophrenia, schizoaffective disorder, personality disorders, substance use disorders, intellectual disabilities and dementia or other neurological diseases including trigeminal neuralgia * Pregnant or breastfeeding women * Participants who are experiencing seizures * Implanted vagal nerve stimulation (VNS) or other electrical devices * Participants who are already undergoing transcutaneous electrical nerve stimulation * Consumption of cannabis, any cannabis by-products, illicit drugs, or alcohol above 3 drinks per week * Consumption of natural health products that may affect anxiety or depression symptoms