Can stopping ADHD medication cause a rebound where symptoms come back worse than before?

Real effect, not imagined, this is actually a well-documented phenomenon with some stimulant ADHD medications, particularly shorter-acting ones, often called rebound effect. As the medication wears off, especially if it wears off relatively abruptly rather than tapering out gradually, some people experience a temporary period where symptoms feel more intense than their normal unmedicated baseline, not just a return to baseline but an overshoot past it. This tends to be more pronounced with immediate-release or certain formulations that have a sharper drop-off, and less pronounced with smoother extended-release formulations, which is one of the things your provider considers when choosing which medication and formulation fits your life, not just the type but the release profile. A couple of missed days specifically can also just genuinely be your body reacting to the disruption of a routine your system had adjusted to, not necessarily a formal 'rebound' in the strict pharmacological sense, but functionally it can feel similar and is worth mentioning to your provider either way. If this happens more than occasionally, or feels severe, that's genuinely worth a conversation about whether your current formulation's drop-off pattern is the right fit, rather than something to just push through as an expected cost of the medication.

Happened to me on my old immediate-release prescription pretty reliably every evening as it wore off, switched to an extended-release formulation and that specific crash-feeling mostly disappeared, worth asking if formulation is part of what's going on for you too.