Friend has ADHD and takes 2 ritalins (methylphenidate) a day what would happen if I took some to study for something?

Stupid idea. Medications should only be taken by those for whom they were prescribed. Taking someone else's medication, particularly a controlled substance, is called "diversion." this is a federal offense that if applied, could land you in jail with a large fine. If u feel u need help to study, u should contact your doctor or a specialist in learning disorders to see why you need chemical help to study.
Never a good idea. You would not want to use someone else's toothbrush. Why would you want to take their meds? Although these medications do help with focus and attention on pts without adhd. They are controlled substances, prescribed to be used only by the recepient, they have side effects, adverse reactions, contraindications and possible allergic reactions. Finally because it is not legal!
Adhd. Stimulants can have certain serious side effects and risk is higher if you don 't have adhd. So evaluation by a physician. Is important to determine if you need stimulants.
Don't do it! It is never a good idea to take someone else's medication. Ritalin (methylphenidate) is an amphetamine type drug and could cause a serious adverse effect.