Yes happiness is a state of mind. More precisely it is rush of chemicals in your brain (sounds unsexy!). Yes you can be administered with chemicals to feel happiness!
This is what drugs do. They trigger release of dopamine in your brain. Similar thing happens when we feel good, are in love, do sex, accomplish some thing important etc.
Now happiness is NOT bliss.
Bliss, which had been described by quite a few eminent people throughout history, starting from Buddha to Jesus to Kabir to Osho…is happiness without reason. If you are always releasing dopamine in your brain without any cause and effect, you get enlightened.
Happiness is getting a water bottle whenever you feel thirsty. Bliss is having the lake besides you with unlimited supply.