If you need answer to your question then visit mental health professional. If your child is not responding well or not speaking a word etc then it might be adhd but there are various other psychological conditionals like autism, dyslexia which are treatable so a psychologist can help you. You should check symptoms of adhd disorder first and if you found symptoms are same then do not wait. You can start here http://illnessquiz.com/adhd-test/ and then visit mental health expert for treatment. Hope i can help

Thanks