This is a feasibility study for trigeminal nerve stimulation (TNS) in patients with treatment-resistant generalized anxiety disorder (TR-GAD). Ten participants will receive TNS for 8 weeks as an augmentation strategy to pharmacological treatment for generalized anxiety disorder (GAD).
- The primary objective is to ascertain if TNS is a safe and well-tolerated treatment for patients with TR-GAD.
- The secondary objective will be to monitor changes in GAD symptom severity throughout the study.
Results from this study will inform a randomized controlled trial to be conducted in the future.
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