major depressive disorde
"I've been off and on of this medication for about 8 years. I originally started it to help me quit smoking (which worked wonders for me, I was able to quit) and later was put back on it for seasonal depression disorder. It helps me a lot with depression, especially as it worsens in the winter. 
Side effects I experience is increased anxiety, heart palpitations, increased heart rate. 
I've been on 300 mg (150mg twice a day) before and my anxiety was horrible. If you're on a higher dose and suffer with anxiety you may want to try a lower dose. I currently take 150 mg a day and it's very helpful. It gives you that spark of motivation you need in the mornings."