I'm going to be taking vyvanse (lisdexamfetamine) for the first time, can you tell me what to expect?

Assume for ADHD/ADD: You should expect that you will be more focused and be able to concentrate better. You will be less distractible. Your energy should be better and should have less of a tendency to be forgetful. You should feel calmer. You should find yourself better able to complete tasks and to be less of a procrastinator. The best you may find yourself speaking less, more appropriately, and interrupting others less.It should be easier to focus on one task.You may experience a mild increase in anxiety if you are an anxious person. Any internal restlessness however should begin to die down.You may experience a decrease in appetite and some difficulty with insomnia. Your doctor can help you with both of those. Best wishes.