There are some amino acids which, when taken on an empty stomach, can improve dopamine levels. Probably not as effective as Adderall, but the issue with prescription meds like this is that they tend to lose their effectiveness when taken over long periods of time.
I have some symptoms of ADD-PI, but I prefer to take legal, unregulated cognition enhancers such as piracetam, aniracetam, Noopept, sulbutiamine, idebenone, and magnesium l-threonate. They have a profound effect on mental flexibility, memory, focus, and verbal ability. These supplements should be cycled. Their effect appears to be cumulative when used properly over extended periods.