The dynamic developmental theory of attention-deficit/hyperactivity disorder (ADHD) proposes that hypodopaminergic functioning results in anomalous delay-of-reinforcement gradients in ADHD, which in turn might account for many of the observed behavioral and cognitive characteristics. However, hyperdopaminergic functioning might also impair mnemonic representation of codes for spatial, motoric, and reward information and contribute to the purported shorter delay gradients in ADHD.