Dopamine and Serotonin are neurotransmitters that are also associated with addiction. Low levels of serotonin cause depression and insomnia. 
These increase the levels;
Free Range Turkey
Flaxseed/ Flaxseed oil
Buckwheat
Wild Fish and Sea food
Whey protein
Bananas
High quality Eggs
Sour Cherries
Free Range Beef
Dark Chocolate