Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental condition. It's not a mental health condition or a learning disability. But having ADHD might affect your mental health, and some people with ADHD might also have a mental health condition like anxiety or depression. ADHD traits usualy start before the age of six, but you can be diagnosed at any age. Some people don't realise they have ADHD until they're much older. ADHD can be different for everyone and depend on your age, sex, gender identity and if you have any other neurodevelopmental condition.