Grant: CIHR Fellowship

Depression affects about 20% of the population in their lifetime and is now the leading cause of illness burden worldwide. It is usually treated with either medications or psychotherapy but a substantial number of people do not respond to these treatments. In this case, a treatment known as electroconvulsive therapy (ECT) may be offered. ECT uses electricity delivered under anesthesia to induce a generalized seizure, which is thought to be safe and effective for depression. Numerous clinical trials of ECT have shown it to be effective in treating depression and reducing suicidal thoughts. Furthermore, recent work using administrative health data from Ontario found extremely low rates of adverse medical events (AME) - similar to low-risk outpatient surgeries. Despite this, <1% of depressed individuals receive ECT which may be due to lack of knowledge about ECT's relationship with patient-relevant outcomes for AME (death or hospitalization) and suicide (attempted or completed). We do not currently know the specific contribution of ECT to either of these outcomes as individuals with depression have higher rates for both. Determining the specific contribution of ECT to suicide or AME requires comparing large groups of individuals who receive ECT to a group of similar individuals who do not receive ECT. While there have been previous studies comparing individuals receiving ECT to those not, these have been limited by differences between groups and were conducted in a single location. Therefore, our goal is to compare depressed individuals who receive ECT to a closely matched group of individuals who do not receive ECT using data from the province of Ontario. We hypothesize individuals who receive ECT will have a slightly increased risk of AME (due to the anesthesia required for ECT) but reduced risk of suicide (due to the effectiveness of ECT for treating depression). We believe this knowledge will improve patients' ability to make effective decisions regarding ECT.