Causes of ADHD

A woman's health habits while pregnant could increase her child's risk of ADHD.(ISTOCKPHOTO)

Attention deficit hyperactivity disorder (ADHD) always begins in childhood, although it is sometimes not recognized or diagnosed for many years. Scientists know that the disorder is largely genetic: A child who has ADHD has about a 30% to 40% chance of having a parent with ADHD as well.

However, some environmental factors—such as drinking and smoking during pregnancy—seem to play a role as well.