“The reward center is where ADHD and addiction overlap, which explains why both problems undermine motivation, self-control, and memory. It is no coincidence that about half of those with ADHD also struggle with substance abuse of some kind. The implications have changed the way scientists describe addiction. The pivotal issues seem to be salience and motivation rather than pleasure. In this context, salience means something that stands out against the landscape of life, predominating over all other stimuli. Cues for both pleasure and pain send dopamine coursing through the nucleus accumbens to attract our attention so we can take action to survive. For the developing substance abuser, the overload of dopamine has tricked the brain into thinking that paying attention to the drug is a matter of life or death. “Drugs are tapping into the very core systems that have evolved to mediate survival,” says Robinson. “They activate the system in ways it was never meant to be activated.”