ADHD is strongly genetic, with prenatal factors like maternal smoking and drinking also implicated, and many linked genes center on brain reward pathways; fewer dopamine receptors make everyday rewards feel underwhelming, fueling boredom. Brain scans reveal a default mode network that fails to quiet when focus is needed, competing with the task-positive network, while a thinner prefrontal cortex undermines attention control, emotional regulation, and response inhibition. Ritalin raises synaptic dopamine to compensate for fewer receptors, but findings on its effectiveness conflict, long-term side effects remain uncertain, and some non-ADHD users misuse it to boost concentration at school or work. Diagnoses have risen about 5% annually in the U.S. from 2003–2011, with dispensed prescriptions up roughly 35% from 2008–2012, intensifying debate over appropriateness. From an evolutionary view, restlessness and hyperactivity aided hunter-gatherer foraging and vigilance—mirrored in Ariaal nomads with more ADHD-linked genes who secured more food—and the same traits, alongside outside-the-box creativity, can become strengths in careers demanding resourcefulness and adaptability despite challenges in rigid classrooms.