Saying there will be a cure to depression like we have with other diseases is a bit like saying there will eventually be a spray-on lubricant that can magically fix any malfunctioning machine. It really oversimplifies the problem. We'll get better and better at treating depression, but I don't think it will ever be an easy fix until we have nanomachines that can reprogram our brains.
A simple spray-on fix (‘Take this pill daily for the next two weeks and everything will be fabulous’) is indeed likely an oversimplification. However, we are making progress treating cancer, HIV and hundreds of other diseases and bodily malfunctions, and I see little reason to be that pessimistic about treating psychological malfunctions. Just recall how far medicine got in the last 100 years and how much faster research moves forward nowadays than it did during most of that time. Sure, there won’t be an easy treatment any time soon, but I’m sure that there will be an effective treatment.
And even if you think that nanomachines reprogramming the brain are absolutely necessary to treat depression, I can assure you that people work on that, too.
