Background and Rationale: Suicide is the second leading cause of death in Canadian Emerging
Adults (EAs; 18-24yrs). Current treatments for suicidal thoughts and behaviors are limited
and novel treatments are required to save lives. Transcranial Magnetic Stimulation (TMS) is a
non-invasive neurostimulation treatment for major depressive disorder, a mental health
condition at high risk for suicide. It is well tolerated and effective. However, in the child
and youth population, it does not appear to be superior to sham-TMS. Therefore, strategies
for enhancing TMS outcomes are required.
Over time, TMS can change the function of brain regions important in depression to reduce the
symptoms of depression, including suicidal ideation. The investigators believe this occurs
through a process called 'synaptic plasticity', or the process by which neurons change their
connectivity with other neurons in an activity-dependent manner. Using an adjunct to
facilitate these changes in the EA population may improve TMS outcomes, including its effect
on suicidal ideation.
The investigators' previous data indicates that, in adults, the effects of a TMS protocol
called intermittent theta-burst stimulation (iTBS) can be enhanced by pairing stimulation
with a medication called D-Cycloserine. This FDA-approved medication leads to enhanced
synaptic plasticity with iTBS. In adults, this combination led to greater improvements in
depression symptoms, with a notable rapid resolution of suicidal thoughts as well as
improvements on a computerized test that is associated with future suicidal behavior.
Research Question and Objectives: To conduct a 2-week double-blind placebo-controlled
randomized clinical trial where 60 participants will be randomly assigned to one of two
groups: 1) accelerated iTBS+D-Cycloserine, and 2) accelerated iTBS+placebo. Participants will
receive a weight-based dose of D-Cycloserine or placebo as an adjunct to iTBS (25mg/17.5kg of
body weight).