The “crash” you describe is often referred to as rebound. It’s discussed much more often in relation to children, but it can happen to anyone taking these medications.
There are a few ways to address this issue:
1. Overlapping doses very slightly when taking short-acting formulations so it doesn’t wear off entirely during the day.
2. Taking a long-acting formula (if that affects sleep, there are ways to combat that, including melatonin, taking it earlier in the day, etc. Ask your doctor about this).
3. Changing medication: There are two types of stimulants: amphetamine (Adderall, Vyvanse, Evekeo…) and methylphenidate (Ritalin, Concerta, Quillivant…). Almost everyone does well on one type or the other, but not both. It may be that you’d do better on a methylphenidate, or even just a different amphetamine. There are many ADHD medications on the market to try, and they are not all the same (they’re all different).
ADDitude Community Moderator, Author & Mentor on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism