Aug 15, - Though it's called adult ADHD, symptoms start in early childhood and continue into adulthood. Adult ADHD symptoms may not be as clear as ADHD symptoms in children. In adults, hyperactivity may decrease, but struggles with impulsiveness, restlessness and difficulty paying attention may continue. May 10, - Here are 10 potential warning signs of adult ADHD: If you're the person with ADHD, you may not understand why your partner While many children with ADHD are “hyperactive,” this ADHD symptom often appears differently in adults. . WebMD does not provide medical advice, diagnosis or treatment.