Ritalin is a brand name for methylphenidate, a mild stimulant drug. It is almost identical to a drug called Dexedrine (dexamphetamine). In very large doses, both Ritalin and Dexedrine would be classified as speed, since that is just a street name for any upper (cocaine, amphetamine, methamphetamine etc.).

Ritalin stays in the body longer than street drugs do and, for people who can't concentrate of who have emotional outbursts, it helps to give them self-control too.

One of the side effects of stimulants is trouble getting to sleep. Usually this wears off within a week or so, but if it goes on, your doctor can adjust your dose or offer a different treatment.

People who have ADD do often see and hear things that are not there. That's also one of the symptoms of ODD (oppositional defiant disorder). These problems are diagnosed by a combination of your behaviour and actions, and by experiences like not being able to concentrate, or having emotional outbursts, plus things like seeing or hearing things.

A lack of sleep can also cause people to have hallucinations (seeing and hearing things). Also, the human brain doesn't cope very well with even small amounts of alcohol until it has matured more than it has by 15 years. Stay off the drink for a couple more years and a lot of these problems might just be history.