There is no single test for ADHD in adults. Your physician will make a diagnosis after taking a detailed medical history, and interviewing people in your life like parents, and former teachers. Sometimes neuropsychological tests are given when looking for co-occurring conditions, such as learning disabilities. Conditions like mood disorders, OCD, ODD, autism, and sensory processing disorder (SPD), can cause symptoms that mimic those of ADHD. Research now suggests that more than half of all individuals who have ADHD also suffer from at least one co-existing condition, which makes symptom detection and diagnosis difficult.