There isn't one specific thing that can tell you that you have ADHD. Instead, your doctor will make a diagnosis based on information from a number of sources.
Find the Right Doctor
Ask your regular doctor for a referral to one of these specialists, or search for one in your health insurance plan's online directory. A local support group for adults with ADHD may also be able to recommend a doctor near you.
Tests and Exams
Before or during your appointment, you may take psychological tests, like completing a checklist of symptoms or a behavior rating scale. You may also get tested to check for a learning disability or other problems that might be mistaken for ADHD or that people can have at the same time as ADHD, such as depression or anxiety.
Impact on Your Life
Your doctor will ask you questions about the symptoms you've noticed at school or work, your use of drugs and alcohol, your driving record, and your relationships with family and friends. Adults need to meet a lower threshold of symptoms than kids -- 5 out of 9 over the past 6 months -- for a diagnosis.
You might feel embarrassed talking about these things or worry about being judged for the problems they've caused, but it's important to be honest so you can get the help you're looking for.
Everyone has trouble concentrating or staying organized from time to time. But when you have ADHD, your symptoms will cause serious issues for you at work, at school, or at home. Major events in two out of these three areas -- like getting fired from a job, failing classes, and being unable to pay bills on time -- are generally needed for an ADHD diagnosis.
Clues in the Past
Your experiences when you were younger matter, too. To be diagnosed with ADHD, your symptoms must have started in childhood (technically before you were 12), although they might have been different at other times in your life, and they may not have caused you many problems until now.
The doctor might also want to talk with your parents or partner. This isn't about checking on your answers. It's so they can learn more about behaviors you may not notice or remember. Then they can better understand your past and present challenges.
If you have any records -- like performance evaluations from work, copies of any previous psychological test results, or even old report cards from school -- bring them to your appointment.
There are two types of ADHD. You may be diagnosed with the hyperactive/impulsive type if you're often restless, fidgety, interrupting, or can't wait. People with the inattentive type are often unfocused and easily distracted, seem careless and make mistakes, forget or lose things, and have trouble staying organized. You could have a combination of both.
Based on your symptoms, your doctor will suggest treatment, which often includes medication, therapy, and learning strategies to manage your behavior.