“An estimated 2.5% of adults worldwide have ADHD and 4.4% of adults in the U.S. have ADHD. More than half of those who have ADHD also have other behavioral health and mood disorder diagnoses like depression or anxiety.

“When adult ADHD is not attended to, with either therapy or medicine, it results in the adult leaving a trail of incompletions in their path, and leaving things incomplete can cause some people to get anxious or depressed,“ says Dr. Manos. “Many times, adults with ADHD can be diagnosed with a depressive disorder or anxiety disorder because of that very thing.”

For this reason, it’s important to get the diagnosis for adult ADHD correct and identify any underlying causes to provide the best course of treatment. When diagnosing ADHD, doctors look at 18 different symptoms — nine inattentive symptoms and nine hyperactivity symptoms.

Diagnosing ADHD is a 3-step process. When diagnosing an adult for ADHD, a doctor looks for:

• Symptoms of ADHD that are problematic to a person’s life.
• External factors that could be causing the behavior in question.
• The presence of another mental health disorder.”

Cleveland Clinic (18 Symptoms That Could Indicate Adult ADHD)