My short answer is yes, they can terminate your payments based on a refusal of ECT.
Most long-term disability insurance policies require the insured person to receive “reasonable medical care” as a condition of receiving disability payments. The issue then becomes what is reasonable medical care?
When considering the reasonableness of your refusal of care, the Courts would consider three things: 1) the degree of risk the treatment poses to you; 2) the negative consequences to you of not getting this treatment; and 3) the potential benefits you could get from the treatment.
Based on what you are saying, it is likely your refusal to try ECT could result in a denial by the insurance company. ECT is recognized as valid, safe and effective treatment by the Canadian Psychiatric Association and the Canadian Medical Association. Modern ECT is far removed from the turn of the century barbaric ECT techniques that most people associate with ECT.
Everyone has the right to determine what happens to their body. Unfortunately, in the context of disability claims people often have to try unwanted treatments as a condition of receiving disability payments, if such treatments are accepted as reasonable by the medical community.
So what can you do? I encourage you to continue to discuss your concerns with ECT with you psychiatrist to see if he or she can alleviate some of your worries about this treatment. If you tried the ECT it will either work or won’t work. If it doesn’t work, then you will have tried everything and will have established a very strong case for ongoing benefits. You could seek a second opinion; however, I can tell you that modern ECT is widely accepted in the Canadian Medical Community as safe and the potential benefits (in alleviating your depression) outweighs the potential side effects or risks.