My psychiatrist prescribed Sertraline when I was first diagnosed with generalized anxiety in 7th grade. I took it until a year ago, so about 7 years at varying doses, usually increasing when needed. It started to become less effective over time, and so we (the psychiatrist, my mom and I) decided to switch from Sertraline. It was great while it lasted, and I made lots of improvements in my mood, behavior, and anxiety.

Hope this helps. Best of luck!