I will try to answer your questions though I am taking Lamictal more for mood stabilization, I take Prozac for depression.

1. I don't remember.
2. I temporarily felt results at 50mg but now take 75 mg. Doc upped me to 100mg but that dose agitated me so went back to 75mg.
3. I take the extended release so it lasts all day. I take it at night.
4. Neither at 75mg, was activating at 100 mg.