Is weight regain after stopping ADHD medication mostly about appetite coming back, or about routine changes too?

Both tend to play a role. Appetite returning toward its unmedicated baseline is a direct pharmacological effect, but the loss of routine and impulse control that medication was also supporting (regular meal timing, less impulsive snacking, better follow-through on food planning) can independently contribute to weight changes after stopping. It's rarely just one or the other; people who've experienced this often describe it as several ADHD-related factors returning at once rather than a single clean cause. References: https://obesitycanada.ca/healthcare-professionals/adult-clinical-practice-guideline/