Caffeine is a stimulant and can be used to self-medicate ADHD. Whilst not as powerful as prescribed stimulants, many people find it helpful. I am not recommending that anyone else should try it, merely sharing my own experience. I was diagnosed as an adult, but from the age of nine, I took a flask of black coffee to school. In hindsight, I realise I was self-medicating my undiagnosed ADHD. As an adult, I was drinking large amounts of caffeine and energy drinks - each month at work I had to focus on a statistical return, and would get through three or four cups of coffee and four cans of Red Bull in two hours ... a neurotypical would be climbing the walls with 600+ mg of caffeine, but it helped me focus. Your mileage may differ!
