Buprenorphine is an approved treatment for pain and opioid relapse prevention. Buprenorphine has recently shown promise in the treatment of depression and suicidal ideation relatively faster than currently available antidepressants, but its mechanisms in treating these conditions are unknown. Buprenorphine activates the mu opioid receptor in the brain and blocks the kappa opioid receptor. Activation of the mu receptors produces pleasant emotions while the kappa receptors are linked to dysphoria and other negative emotional states. By blocking kappa receptors, buprenorphine may reduce negative emotions and improve suicidal thoughts.~In this project, we will compare buprenorphine to placebo as adjunctive to usual treatments for patients who still have depression and suicidal thoughts despite being treated with adequate antidepressant medications for at least 4 weeks. We hypothesize that suicidal ideation will decrease after two weeks of treatment in the buprenorphine group relative to the placebo group.~Using functional magnetic resonance imaging, we will also examine the effects of buprenorphine on the activity of brain regions involved in the brain's response to negative emotions and test whether these effects are associated with the reduction in suicidal thoughts. This would provide some evidence that the antidepressant and anti-suicidal effects of buprenorphine are related to its kappa opioid receptor blockade.~The mechanism of action of buprenorphine is different from the currently available antidepressants. This study will help understand this mechanism which may help refine the use of buprenorphine in this context. Research in this area may also facilitate the development of new anti-suicidal treatments (i.e., other opioid-active compounds).
This study aims to examine the effect of low-dose buprenorphine as an add-on to treatment-as-usual for suicidal ideation in individuals with major depression, and investigate the functional brain activity related to its potential anti-suicidal effect.