My Son Who Is 28 Has Been Diagnosed With ADHD

My son who is 28 has been diagnosed with ADHD and anixiety. He was going to counseling, but didn't feel it was helpful. He had a hard time doing the suggested meditation. He has trouble at work doing tasks in a timely manor and doesn't digest conversations. He does not sleep well and is a huge worrier. He recently went for a physical and was found to be healthy physically. He went to a CSW who has given options for medicine. What medicine doe you think would be beneficial? His CSW said it could take up to six months to start to feel better.