As someone who has ADHD and is also a heavy marijuana user, I've found the marijuana mostly helps me with the frustration of the ADHD experience. It makes it difficult for the frustration to reach a boiling point and that's what actually makes me productive. Adderall has been WAY more effective at this, though.
Similar experience for me. Marijuana definitely makes me feel stupider, but it slows my brain down enough that I can actually focus on one thing at a time so I actually end up more productive overall. Kind of a worse is better situation. I've found the best combination for me to be XR Adderall with a very low dose of THC. Unfortunately my addictive personality makes not abusing marijuana difficult, so I just don't use it these days.
