Not sure if Im in the right topic, but is ADHD hereditary? MY DSS 13 is a sufferer, (well according to his mum but we have never seen any sign of it when he comes to us at the weekend)and my mother in law believes that my DH had it as a child but it wasnt medically recognised then. When my DS 5 was born my health visitor told me that his progress would have to be monitored for ADHD symptoms. So is it possible that it can be passed down through half brothers?