The causes of ADHD are not yet understood. So far, there is no specific test for ADHD. There is no blood test, genetic test, psychological test, or brain scan that can tell whether a child has ADHD or is at risk for developing ADHD. However, scientists do know that ADHD is a complex neurobiological condition.
Several factors seem to contribute to ADHD. Scientists believe that genes and environmental factors cause subtle brain alterations. In turn, these brain alterations cause problems with behaviour and learning.
Each of these factors is discussed in more detail in this section. Click the links on the left to learn more.