I know this is an older thread, but just wanted to add something.
TMS and ketamine treatment have both been suggested to me by various psychiatrists, so I have researched some, into both treatments.
When I looked into ketamine treatment, I found it was too costly for me to afford.....But, I think if you can afford it, it's certainly worth a try.....As for how effective ketamine treatment is, I read that in some early studies, about 50-70% people experienced significant improvement in depression symptoms........However, research is still ongoing as to how safe and effective ketamine would be over the long term.
When looking into TMS treatment, I found it was also too expensive for me........I did find some statistics on TMS, as to how effective it is......According to what I read, about 50-60% of people experience at least some improvement.......And also, in the people who did experience improvement, about 1/3 of them experienced significant improvement.......TMS is worth a try also, in my opinion.