Which is an ugly road to go down imo.....My advice might be boring but seriously....exercise. Lifting weights and cardio...if you're skinny lean towards the weights....if you're fat lean toward the cardio but do both in some sort of combination that suits you. Combined with healthy eating, it's really the only thing I've ever found to have a real impact on clear thinking without effing up your life. I've tried every drug under the sun. Drugs work ALOT better than exercise and health food....but exercise and health food don't have negative side effects.