Lithium
"I had previously been put on every kind of antidepressant for depresion/anxiety. They all worked horribly; so I stopped all drugs and ceased seeing doctors. 
Then, I felt insanely suicidal- I was absolutely crazed. Luckily my sister urged me to seek help as fast as I could- so I did. I went to see another psychiatrist, and he diagnosed me as bipolar. I started on Lamictal, but that didn't do anything for me. Then I switched to Lithium- THANK GOODNESS I still get depressed, but I never get sucked into a deep suicidal hole like before. I quit the drug for 1 month, which caused me to think about suicide unrelentlessly. Never again will I stop taking Lithium. (Does cause extreme thirst and hand tremors, but well worth it)"