Are there any withdrawal side effects from taking adhd medications?

Yes: Possibly. It depends on the medication. The best course of action is to ask your doctor. Is it a good idea to stop "cold turkey?" in some cases this is ok. In others, it's a really (really!) bad idea. Talk to your doctor. That's the only safe alternative.

Yes: Starting or stopping adhd medications is a mutual decision by patient and doctor, and should not be undertaken by the patient alone. In so doing, the patient's discontinuation symptoms can be avoided or minimized. Your question also begs the question of why you would want to discontinue medications in the first place. Ineffectiveness or adverse reactions should be discussed with your doctor.